Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 2698 insertions, 0 deletions

diff --git a/src/VBox/ValidationKit/utils/fs/FsPerf.cpp b/src/VBox/ValidationKit/utils/fs/FsPerf.cpp
new file mode 100644
index 00000000..5e0d88ff
--- /dev/null
+++ b/src/VBox/ValidationKit/utils/fs/FsPerf.cpp
@@ -0,0 +1,2659 @@
+/* $Id: FsPerf.cpp $ */
+/** @file
+ * FsPerf - File System (Shared Folders) Performance Benchmark.
+ */
+
+/*
+ * Copyright (C) 2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/alloca.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/dir.h>
+#include <iprt/file.h>
+#include <iprt/getopt.h>
+#include <iprt/initterm.h>
+#include <iprt/list.h>
+#include <iprt/mem.h>
+#include <iprt/message.h>
+#include <iprt/param.h>
+#include <iprt/path.h>
+#include <iprt/process.h>
+#include <iprt/rand.h>
+#include <iprt/string.h>
+#include <iprt/stream.h>
+#include <iprt/test.h>
+#include <iprt/time.h>
+#include <iprt/thread.h>
+#include <iprt/zero.h>
+
+#ifdef RT_OS_WINDOWS
+# include <iprt/nt/nt-and-windows.h>
+#else
+# include <errno.h>
+# include <unistd.h>
+# include <sys/fcntl.h>
+# include <sys/mman.h>
+# include <sys/types.h>
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/**
+ * Macro for profiling @a a_fnCall (typically forced inline) for about @a a_cNsTarget ns.
+ *
+ * Always does an even number of iterations.
+ */
+#define PROFILE_FN(a_fnCall, a_cNsTarget, a_szDesc) \
+    do { \
+        /* Estimate how many iterations we need to fill up the given timeslot: */ \
+        fsPerfYield(); \
+        uint64_t nsStart = RTTimeNanoTS(); \
+        uint64_t ns; \
+        do \
+            ns = RTTimeNanoTS(); \
+        while (ns == nsStart); \
+        nsStart = ns; \
+        \
+        uint64_t iIteration = 0; \
+        do \
+        { \
+            RTTESTI_CHECK_RC(a_fnCall, VINF_SUCCESS); \
+            iIteration++; \
+            ns = RTTimeNanoTS() - nsStart; \
+        } while (ns < RT_NS_10MS || (iIteration & 1)); \
+        ns /= iIteration; \
+        if (ns > g_nsPerNanoTSCall + 32) \
+            ns -= g_nsPerNanoTSCall; \
+        \
+        uint64_t cIterations = (a_cNsTarget) / ns; \
+        if (cIterations <= 1) \
+            cIterations = 2; \
+        else if (cIterations & 1) \
+            cIterations++; \
+        \
+        /* Do the actual profiling: */ \
+        fsPerfYield(); \
+        iIteration = 0; \
+        nsStart = RTTimeNanoTS(); \
+        for (; iIteration < cIterations; iIteration++) \
+            RTTESTI_CHECK_RC(a_fnCall, VINF_SUCCESS); \
+        ns = RTTimeNanoTS() - nsStart; \
+        RTTestIValueF(ns / cIterations, RTTESTUNIT_NS_PER_OCCURRENCE, a_szDesc); \
+        if (g_fShowDuration) \
+            RTTestIValueF(ns, RTTESTUNIT_NS, "%s duration", a_szDesc); \
+    } while (0)
+
+
+/**
+ * Macro for profiling an operation on each file in the manytree directory tree.
+ *
+ * Always does an even number of tree iterations.
+ */
+#define PROFILE_MANYTREE_FN(a_szPath, a_fnCall, a_cEstimationIterations, a_cNsTarget, a_szDesc) \
+    do { \
+        if (!g_fManyFiles) \
+            break; \
+        \
+        /* Estimate how many iterations we need to fill up the given timeslot: */ \
+        fsPerfYield(); \
+        uint64_t nsStart = RTTimeNanoTS(); \
+        uint64_t ns; \
+        do \
+            ns = RTTimeNanoTS(); \
+        while (ns == nsStart); \
+        nsStart = ns; \
+        \
+        PFSPERFNAMEENTRY pCur; \
+        uint64_t iIteration = 0; \
+        do \
+        { \
+            RTListForEach(&g_ManyTreeHead, pCur, FSPERFNAMEENTRY, Entry) \
+            { \
+                memcpy(a_szPath, pCur->szName, pCur->cchName); \
+                for (uint32_t i = 0; i < g_cManyTreeFilesPerDir; i++) \
+                { \
+                    RTStrFormatU32(&a_szPath[pCur->cchName], sizeof(a_szPath) - pCur->cchName, i, 10, 5, 5, RTSTR_F_ZEROPAD); \
+                    RTTESTI_CHECK_RC(a_fnCall, VINF_SUCCESS); \
+                } \
+            } \
+            iIteration++; \
+            ns = RTTimeNanoTS() - nsStart; \
+        } while (ns < RT_NS_10MS || (iIteration & 1)); \
+        ns /= iIteration; \
+        if (ns > g_nsPerNanoTSCall + 32) \
+            ns -= g_nsPerNanoTSCall; \
+        \
+        uint32_t cIterations = (a_cNsTarget) / ns; \
+        if (cIterations <= 1) \
+            cIterations = 2; \
+        else if (cIterations & 1) \
+            cIterations++; \
+        \
+        /* Do the actual profiling: */ \
+        fsPerfYield(); \
+        uint32_t cCalls = 0; \
+        nsStart = RTTimeNanoTS(); \
+        for (iIteration = 0; iIteration < cIterations; iIteration++) \
+        { \
+            RTListForEach(&g_ManyTreeHead, pCur, FSPERFNAMEENTRY, Entry) \
+            { \
+                memcpy(a_szPath, pCur->szName, pCur->cchName); \
+                for (uint32_t i = 0; i < g_cManyTreeFilesPerDir; i++) \
+                { \
+                    RTStrFormatU32(&a_szPath[pCur->cchName], sizeof(a_szPath) - pCur->cchName, i, 10, 5, 5, RTSTR_F_ZEROPAD); \
+                    RTTESTI_CHECK_RC(a_fnCall, VINF_SUCCESS); \
+                    cCalls++; \
+                } \
+            } \
+        } \
+        ns = RTTimeNanoTS() - nsStart; \
+        RTTestIValueF(ns / cCalls, RTTESTUNIT_NS_PER_OCCURRENCE, a_szDesc); \
+        if (g_fShowDuration) \
+            RTTestIValueF(ns, RTTESTUNIT_NS, "%s duration", a_szDesc); \
+    } while (0)
+
+
+/**
+ * Execute a_fnCall for each file in the manytree.
+ */
+#define DO_MANYTREE_FN(a_szPath, a_fnCall) \
+    do { \
+        PFSPERFNAMEENTRY pCur; \
+        RTListForEach(&g_ManyTreeHead, pCur, FSPERFNAMEENTRY, Entry) \
+        { \
+            memcpy(a_szPath, pCur->szName, pCur->cchName); \
+            for (uint32_t i = 0; i < g_cManyTreeFilesPerDir; i++) \
+            { \
+                RTStrFormatU32(&a_szPath[pCur->cchName], sizeof(a_szPath) - pCur->cchName, i, 10, 5, 5, RTSTR_F_ZEROPAD); \
+                a_fnCall; \
+            } \
+        } \
+    } while (0)
+
+
+/** @def FSPERF_VERR_PATH_NOT_FOUND
+ * Hides the fact that we only get VERR_PATH_NOT_FOUND on non-unix systems.  */
+#if defined(RT_OS_WINDOWS) //|| defined(RT_OS_OS2) - using posix APIs IIRC, so lost in translation.
+# define FSPERF_VERR_PATH_NOT_FOUND     VERR_PATH_NOT_FOUND
+#else
+# define FSPERF_VERR_PATH_NOT_FOUND     VERR_FILE_NOT_FOUND
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct FSPERFNAMEENTRY
+{
+    RTLISTNODE  Entry;
+    uint16_t    cchName;
+    char        szName[RT_FLEXIBLE_ARRAY];
+} FSPERFNAMEENTRY;
+typedef FSPERFNAMEENTRY *PFSPERFNAMEENTRY;
+
+
+enum
+{
+    kCmdOpt_First = 128,
+
+    kCmdOpt_ManyFiles = kCmdOpt_First,
+    kCmdOpt_NoManyFiles,
+    kCmdOpt_Open,
+    kCmdOpt_NoOpen,
+    kCmdOpt_FStat,
+    kCmdOpt_NoFStat,
+    kCmdOpt_FChMod,
+    kCmdOpt_NoFChMod,
+    kCmdOpt_FUtimes,
+    kCmdOpt_NoFUtimes,
+    kCmdOpt_Stat,
+    kCmdOpt_NoStat,
+    kCmdOpt_ChMod,
+    kCmdOpt_NoChMod,
+    kCmdOpt_Utimes,
+    kCmdOpt_NoUtimes,
+    kCmdOpt_Rename,
+    kCmdOpt_NoRename,
+    kCmdOpt_DirEnum,
+    kCmdOpt_NoDirEnum,
+    kCmdOpt_MkRmDir,
+    kCmdOpt_NoMkRmDir,
+    kCmdOpt_StatVfs,
+    kCmdOpt_NoStatVfs,
+    kCmdOpt_Rm,
+    kCmdOpt_NoRm,
+    kCmdOpt_ChSize,
+    kCmdOpt_NoChSize,
+    kCmdOpt_Read,
+    kCmdOpt_NoRead,
+    kCmdOpt_Write,
+    kCmdOpt_NoWrite,
+    kCmdOpt_Seek,
+    kCmdOpt_NoSeek,
+    kCmdOpt_FSync,
+    kCmdOpt_NoFSync,
+    kCmdOpt_MMap,
+    kCmdOpt_NoMMap,
+
+    kCmdOpt_End
+};
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Command line parameters */
+static const RTGETOPTDEF g_aCmdOptions[] =
+{
+    { "--dir",              'd', RTGETOPT_REQ_STRING  },
+    { "--seconds",          's', RTGETOPT_REQ_UINT32  },
+    { "--milliseconds",     'm', RTGETOPT_REQ_UINT64  },
+
+    { "--enable-all",       'e', RTGETOPT_REQ_NOTHING },
+    { "--disable-all",      'z', RTGETOPT_REQ_NOTHING },
+
+    { "--many-files",       kCmdOpt_ManyFiles,      RTGETOPT_REQ_NOTHING },
+    { "--no-many-files",    kCmdOpt_NoManyFiles,    RTGETOPT_REQ_NOTHING },
+
+    { "--open",             kCmdOpt_Open,           RTGETOPT_REQ_NOTHING },
+    { "--no-open",          kCmdOpt_NoOpen,         RTGETOPT_REQ_NOTHING },
+    { "--fstat",            kCmdOpt_FStat,          RTGETOPT_REQ_NOTHING },
+    { "--no-fstat",         kCmdOpt_NoFStat,        RTGETOPT_REQ_NOTHING },
+    { "--fchmod",           kCmdOpt_FChMod,         RTGETOPT_REQ_NOTHING },
+    { "--no-fchmod",        kCmdOpt_NoFChMod,       RTGETOPT_REQ_NOTHING },
+    { "--futimes",          kCmdOpt_FUtimes,        RTGETOPT_REQ_NOTHING },
+    { "--no-futimes",       kCmdOpt_NoFUtimes,      RTGETOPT_REQ_NOTHING },
+    { "--stat",             kCmdOpt_Stat,           RTGETOPT_REQ_NOTHING },
+    { "--no-stat",          kCmdOpt_NoStat,         RTGETOPT_REQ_NOTHING },
+    { "--chmod",            kCmdOpt_ChMod,          RTGETOPT_REQ_NOTHING },
+    { "--no-chmod",         kCmdOpt_NoChMod,        RTGETOPT_REQ_NOTHING },
+    { "--utimes",           kCmdOpt_Utimes,         RTGETOPT_REQ_NOTHING },
+    { "--no-utimes",        kCmdOpt_NoUtimes,       RTGETOPT_REQ_NOTHING },
+    { "--rename",           kCmdOpt_Rename,         RTGETOPT_REQ_NOTHING },
+    { "--no-rename",        kCmdOpt_NoRename,       RTGETOPT_REQ_NOTHING },
+    { "--dir-enum",         kCmdOpt_DirEnum,        RTGETOPT_REQ_NOTHING },
+    { "--no-dir-enum",      kCmdOpt_NoDirEnum,      RTGETOPT_REQ_NOTHING },
+    { "--mk-rm-dir",        kCmdOpt_MkRmDir,        RTGETOPT_REQ_NOTHING },
+    { "--no-mk-rm-dir",     kCmdOpt_NoMkRmDir,      RTGETOPT_REQ_NOTHING },
+    { "--stat-vfs",         kCmdOpt_StatVfs,        RTGETOPT_REQ_NOTHING },
+    { "--no-stat-vfs",      kCmdOpt_NoStatVfs,      RTGETOPT_REQ_NOTHING },
+    { "--rm",               kCmdOpt_Rm,             RTGETOPT_REQ_NOTHING },
+    { "--no-rm",            kCmdOpt_NoRm,           RTGETOPT_REQ_NOTHING },
+    { "--chsize",           kCmdOpt_ChSize,         RTGETOPT_REQ_NOTHING },
+    { "--no-chsize",        kCmdOpt_NoChSize,       RTGETOPT_REQ_NOTHING },
+    { "--read",             kCmdOpt_Read,           RTGETOPT_REQ_NOTHING },
+    { "--no-read",          kCmdOpt_NoRead,         RTGETOPT_REQ_NOTHING },
+    { "--write",            kCmdOpt_Write,          RTGETOPT_REQ_NOTHING },
+    { "--no-write",         kCmdOpt_NoWrite,        RTGETOPT_REQ_NOTHING },
+    { "--seek",             kCmdOpt_Seek,           RTGETOPT_REQ_NOTHING },
+    { "--no-seek",          kCmdOpt_NoSeek,         RTGETOPT_REQ_NOTHING },
+    { "--fsync",            kCmdOpt_FSync,          RTGETOPT_REQ_NOTHING },
+    { "--no-fsync",         kCmdOpt_NoFSync,        RTGETOPT_REQ_NOTHING },
+    { "--mmap",             kCmdOpt_MMap,           RTGETOPT_REQ_NOTHING },
+    { "--no-mmap",          kCmdOpt_NoMMap,         RTGETOPT_REQ_NOTHING },
+
+    { "--quiet",            'q', RTGETOPT_REQ_NOTHING },
+    { "--verbose",          'v', RTGETOPT_REQ_NOTHING },
+    { "--version",          'V', RTGETOPT_REQ_NOTHING },
+    { "--help",             'h', RTGETOPT_REQ_NOTHING } /* for Usage() */
+};
+
+/** The test handle. */
+static RTTEST       g_hTest;
+/** The number of nanoseconds a RTTimeNanoTS call takes.
+ * This is used for adjusting loop count estimates.  */
+static uint64_t     g_nsPerNanoTSCall = 1;
+/** Whether or not to display the duration of each profile run.
+ * This is chiefly for verify the estimate phase.  */
+static bool         g_fShowDuration = true;
+/** Verbosity level. */
+static uint32_t     g_uVerbosity = 0;
+
+/** @name Selected subtest
+ * @{ */
+static bool         g_fManyFiles = true;
+static bool         g_fOpen      = true;
+static bool         g_fFStat     = true;
+static bool         g_fFChMod    = true;
+static bool         g_fFUtimes   = true;
+static bool         g_fStat      = true;
+static bool         g_fChMod     = true;
+static bool         g_fUtimes    = true;
+static bool         g_fRename    = true;
+static bool         g_fDirEnum   = true;
+static bool         g_fMkRmDir   = true;
+static bool         g_fStatVfs   = true;
+static bool         g_fRm        = true;
+static bool         g_fChSize    = true;
+static bool         g_fRead      = true;
+static bool         g_fWrite     = true;
+static bool         g_fSeek      = true;
+static bool         g_fFSync     = true;
+static bool         g_fMMap      = true;
+/** @} */
+
+/** The length of each test run. */
+static uint64_t     g_nsTestRun                 = RT_NS_1SEC_64 * 10;
+
+/** For the 'manyfiles' subdir.  */
+static uint32_t     g_cManyFiles                = 10000;
+
+/** Number of files in the 'manytree' directory tree.  */
+static uint32_t     g_cManyTreeFiles            = 640 + 16*640 /*10880*/;
+/** Number of files per directory in the 'manytree' construct. */
+static uint32_t     g_cManyTreeFilesPerDir      = 640;
+/* Number of subdirs per directory in the 'manytree' construct. */
+static uint32_t     g_cManyTreeSubdirsPerDir    = 16;
+/** The depth of the 'manytree' directory tree.  */
+static uint32_t     g_cManyTreeDepth            = 1;
+/** List of directories in the many tree, creation order. */
+static RTLISTANCHOR g_ManyTreeHead;
+
+/** Number of configured I/O block sizes. */
+static uint32_t     g_cIoBlocks                 = 8;
+/** Configured I/O block sizes. */
+static uint32_t     g_acbIoBlocks[16]           = { 1, 512, 4096, 16384, 65536, _1M, _32M, _128M };
+/** The desired size of the test file we use for I/O. */
+static uint64_t     g_cbIoFile                  = _512M;
+
+/** The length of g_szDir. */
+static size_t       g_cchDir;
+/** The length of g_szEmptyDir. */
+static size_t       g_cchEmptyDir;
+/** The length of g_szDeepDir. */
+static size_t       g_cchDeepDir;
+
+/** The test directory (absolute).  This will always have a trailing slash. */
+static char         g_szDir[RTPATH_MAX];
+/** The empty test directory (absolute). This will always have a trailing slash. */
+static char         g_szEmptyDir[RTPATH_MAX];
+/** The deep test directory (absolute). This will always have a trailing slash. */
+static char         g_szDeepDir[RTPATH_MAX];
+
+
+/**
+ * Yield the CPU and stuff before starting a test run.
+ */
+DECLINLINE(void) fsPerfYield(void)
+{
+    RTThreadYield();
+    RTThreadYield();
+}
+
+
+/**
+ * Profiles the RTTimeNanoTS call, setting g_nsPerNanoTSCall.
+ */
+static void fsPerfNanoTS(void)
+{
+    fsPerfYield();
+
+    /* Make sure we start off on a changing timestamp on platforms will low time resoultion. */
+    uint64_t nsStart = RTTimeNanoTS();
+    uint64_t ns;
+    do
+        ns = RTTimeNanoTS();
+    while (ns == nsStart);
+    nsStart = ns;
+
+    /* Call it for 10 ms. */
+    uint32_t i = 0;
+    do
+    {
+        i++;
+        ns = RTTimeNanoTS();
+    }
+    while (ns - nsStart < RT_NS_10MS);
+
+    g_nsPerNanoTSCall = (ns - nsStart) / i;
+}
+
+
+/**
+ * Construct a path relative to the base test directory.
+ *
+ * @returns g_szDir.
+ * @param   pszAppend           What to append.
+ * @param   cchAppend           How much to append.
+ */
+DECLINLINE(char *) InDir(const char *pszAppend, size_t cchAppend)
+{
+    Assert(g_szDir[g_cchDir - 1] == RTPATH_SLASH);
+    memcpy(&g_szDir[g_cchDir], pszAppend, cchAppend);
+    g_szDir[g_cchDir + cchAppend] = '\0';
+    return &g_szDir[0];
+}
+
+
+/**
+ * Construct a path relative to the empty directory.
+ *
+ * @returns g_szEmptyDir.
+ * @param   pszAppend           What to append.
+ * @param   cchAppend           How much to append.
+ */
+DECLINLINE(char *) InEmptyDir(const char *pszAppend, size_t cchAppend)
+{
+    Assert(g_szEmptyDir[g_cchEmptyDir - 1] == RTPATH_SLASH);
+    memcpy(&g_szEmptyDir[g_cchEmptyDir], pszAppend, cchAppend);
+    g_szEmptyDir[g_cchEmptyDir + cchAppend] = '\0';
+    return &g_szEmptyDir[0];
+}
+
+
+/**
+ * Construct a path relative to the deep test directory.
+ *
+ * @returns g_szDeepDir.
+ * @param   pszAppend           What to append.
+ * @param   cchAppend           How much to append.
+ */
+DECLINLINE(char *) InDeepDir(const char *pszAppend, size_t cchAppend)
+{
+    Assert(g_szDeepDir[g_cchDeepDir - 1] == RTPATH_SLASH);
+    memcpy(&g_szDeepDir[g_cchDeepDir], pszAppend, cchAppend);
+    g_szDeepDir[g_cchDeepDir + cchAppend] = '\0';
+    return &g_szDeepDir[0];
+}
+
+
+/**
+ * Prepares the test area.
+ * @returns VBox status code.
+ */
+static int fsPrepTestArea(void)
+{
+    /* The empty subdir and associated globals: */
+    static char s_szEmpty[] = "empty";
+    memcpy(g_szEmptyDir, g_szDir, g_cchDir);
+    memcpy(&g_szEmptyDir[g_cchDir], s_szEmpty, sizeof(s_szEmpty));
+    g_cchEmptyDir = g_cchDir + sizeof(s_szEmpty) - 1;
+    RTTESTI_CHECK_RC_RET(RTDirCreate(g_szEmptyDir, 0755, 0), VINF_SUCCESS, rcCheck);
+    g_szEmptyDir[g_cchEmptyDir++] = RTPATH_SLASH;
+    g_szEmptyDir[g_cchEmptyDir]   = '\0';
+    RTTestIPrintf(RTTESTLVL_ALWAYS, "Empty dir: %s\n", g_szEmptyDir);
+
+    /* Deep directory: */
+    memcpy(g_szDeepDir, g_szDir, g_cchDir);
+    g_cchDeepDir = g_cchDir;
+    do
+    {
+        static char const s_szSub[] = "d" RTPATH_SLASH_STR;
+        memcpy(&g_szDeepDir[g_cchDeepDir], s_szSub, sizeof(s_szSub));
+        g_cchDeepDir += sizeof(s_szSub) - 1;
+        RTTESTI_CHECK_RC_RET( RTDirCreate(g_szDeepDir, 0755, 0), VINF_SUCCESS, rcCheck);
+    } while (g_cchDeepDir < 176);
+    RTTestIPrintf(RTTESTLVL_ALWAYS, "Deep  dir: %s\n", g_szDeepDir);
+
+    /* Create known file in both deep and shallow dirs: */
+    RTFILE hKnownFile;
+    RTTESTI_CHECK_RC_RET(RTFileOpen(&hKnownFile, InDir(RT_STR_TUPLE("known-file")),
+                                    RTFILE_O_CREATE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE),
+                         VINF_SUCCESS, rcCheck);
+    RTTESTI_CHECK_RC_RET(RTFileClose(hKnownFile), VINF_SUCCESS, rcCheck);
+
+    RTTESTI_CHECK_RC_RET(RTFileOpen(&hKnownFile, InDeepDir(RT_STR_TUPLE("known-file")),
+                                    RTFILE_O_CREATE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE),
+                         VINF_SUCCESS, rcCheck);
+    RTTESTI_CHECK_RC_RET(RTFileClose(hKnownFile), VINF_SUCCESS, rcCheck);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Create a name list entry.
+ * @returns Pointer to the entry, NULL if out of memory.
+ * @param   pchName             The name.
+ * @param   cchName             The name length.
+ */
+PFSPERFNAMEENTRY fsPerfCreateNameEntry(const char *pchName, size_t cchName)
+{
+    PFSPERFNAMEENTRY pEntry = (PFSPERFNAMEENTRY)RTMemAllocVar(RT_UOFFSETOF_DYN(FSPERFNAMEENTRY, szName[cchName + 1]));
+    if (pEntry)
+    {
+        RTListInit(&pEntry->Entry);
+        pEntry->cchName         = (uint16_t)cchName;
+        memcpy(pEntry->szName, pchName, cchName);
+        pEntry->szName[cchName] = '\0';
+    }
+    return pEntry;
+}
+
+
+static int fsPerfManyTreeRecursiveDirCreator(size_t cchDir, uint32_t iDepth)
+{
+    PFSPERFNAMEENTRY pEntry = fsPerfCreateNameEntry(g_szDir, cchDir);
+    RTTESTI_CHECK_RET(pEntry, VERR_NO_MEMORY);
+    RTListAppend(&g_ManyTreeHead, &pEntry->Entry);
+
+    RTTESTI_CHECK_RC_RET(RTDirCreate(g_szDir, 0755, RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_DONT_SET | RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_NOT_CRITICAL),
+                         VINF_SUCCESS, rcCheck);
+
+    if (iDepth < g_cManyTreeDepth)
+        for (uint32_t i = 0; i < g_cManyTreeSubdirsPerDir; i++)
+        {
+            size_t cchSubDir = RTStrPrintf(&g_szDir[cchDir], sizeof(g_szDir) - cchDir, "d%02u" RTPATH_SLASH_STR, i);
+            RTTESTI_CHECK_RC_RET(fsPerfManyTreeRecursiveDirCreator(cchDir + cchSubDir, iDepth + 1), VINF_SUCCESS, rcCheck);
+        }
+
+    return VINF_SUCCESS;
+}
+
+
+void fsPerfManyFiles(void)
+{
+    RTTestISub("manyfiles");
+
+    /*
+     * Create a sub-directory with like 10000 files in it.
+     *
+     * This does push the directory organization of the underlying file system,
+     * which is something we might not want to profile with shared folders.  It
+     * is however useful for directory enumeration.
+     */
+    RTTESTI_CHECK_RC_RETV(RTDirCreate(InDir(RT_STR_TUPLE("manyfiles")), 0755,
+                                      RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_DONT_SET | RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_NOT_CRITICAL),
+                          VINF_SUCCESS);
+
+    size_t offFilename = strlen(g_szDir);
+    g_szDir[offFilename++] = RTPATH_SLASH;
+
+    fsPerfYield();
+    RTFILE hFile;
+    uint64_t const nsStart = RTTimeNanoTS();
+    for (uint32_t i = 0; i < g_cManyFiles; i++)
+    {
+        RTStrFormatU32(&g_szDir[offFilename], sizeof(g_szDir) - offFilename, i, 10, 5, 5, RTSTR_F_ZEROPAD);
+        RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile, g_szDir, RTFILE_O_CREATE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+        RTTESTI_CHECK_RC(RTFileClose(hFile), VINF_SUCCESS);
+    }
+    uint64_t const cNsElapsed = RTTimeNanoTS() - nsStart;
+    RTTestIValueF(cNsElapsed, RTTESTUNIT_NS, "Creating %u empty files in single directory", g_cManyFiles);
+    RTTestIValueF(cNsElapsed / g_cManyFiles, RTTESTUNIT_NS_PER_OCCURRENCE, "Create empty file (single dir)");
+
+    /*
+     * Create a bunch of directories with exacly 32 files in each, hoping to
+     * avoid any directory organization artifacts.
+     */
+    /* Create the directories first, building a list of them for simplifying iteration: */
+    RTListInit(&g_ManyTreeHead);
+    InDir(RT_STR_TUPLE("manytree" RTPATH_SLASH_STR));
+    RTTESTI_CHECK_RC_RETV(fsPerfManyTreeRecursiveDirCreator(strlen(g_szDir), 0), VINF_SUCCESS);
+
+    /* Create the zero byte files: */
+    fsPerfYield();
+    uint64_t const nsStart2 = RTTimeNanoTS();
+    uint32_t cFiles = 0;
+    PFSPERFNAMEENTRY pCur;
+    RTListForEach(&g_ManyTreeHead, pCur, FSPERFNAMEENTRY, Entry)
+    {
+        char szPath[RTPATH_MAX];
+        memcpy(szPath, pCur->szName, pCur->cchName);
+        for (uint32_t i = 0; i < g_cManyTreeFilesPerDir; i++)
+        {
+            RTStrFormatU32(&szPath[pCur->cchName], sizeof(szPath) - pCur->cchName, i, 10, 5, 5, RTSTR_F_ZEROPAD);
+            RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile, szPath, RTFILE_O_CREATE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+            RTTESTI_CHECK_RC(RTFileClose(hFile), VINF_SUCCESS);
+            cFiles++;
+        }
+    }
+    uint64_t const cNsElapsed2 = RTTimeNanoTS() - nsStart2;
+    RTTestIValueF(cNsElapsed2, RTTESTUNIT_NS, "Creating %u empty files in tree", cFiles);
+    RTTestIValueF(cNsElapsed2 / cFiles, RTTESTUNIT_NS_PER_OCCURRENCE, "Create empty file (tree)");
+    RTTESTI_CHECK(g_cManyTreeFiles == cFiles);
+}
+
+
+DECL_FORCE_INLINE(int) fsPerfOpenExistingOnceReadonly(const char *pszFile)
+{
+    RTFILE hFile;
+    RTTESTI_CHECK_RC_RET(RTFileOpen(&hFile, pszFile, RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_READ), VINF_SUCCESS, rcCheck);
+    RTTESTI_CHECK_RC(RTFileClose(hFile), VINF_SUCCESS);
+    return VINF_SUCCESS;
+}
+
+
+DECL_FORCE_INLINE(int) fsPerfOpenExistingOnceWriteonly(const char *pszFile)
+{
+    RTFILE hFile;
+    RTTESTI_CHECK_RC_RET(RTFileOpen(&hFile, pszFile, RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS, rcCheck);
+    RTTESTI_CHECK_RC(RTFileClose(hFile), VINF_SUCCESS);
+    return VINF_SUCCESS;
+}
+
+
+void fsPerfOpen(void)
+{
+    RTTestISub("open");
+
+    /* Opening non-existing files. */
+    RTFILE hFile;
+    RTTESTI_CHECK_RC(RTFileOpen(&hFile, InEmptyDir(RT_STR_TUPLE("no-such-file")),
+                                RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_READ), VERR_FILE_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTFileOpen(&hFile, InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file")),
+                                RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_READ), FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTFileOpen(&hFile, InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file")),
+                                RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_READ), VERR_PATH_NOT_FOUND);
+
+    /*
+     * Create file1 and then try exclusivly creating it again.
+     * Then profile opening it for reading.
+     */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file1")),
+                                     RTFILE_O_CREATE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileOpen(&hFile, g_szDir, RTFILE_O_CREATE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VERR_ALREADY_EXISTS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    PROFILE_FN(fsPerfOpenExistingOnceReadonly(g_szDir),  g_nsTestRun, "RTFileOpen/Close/Readonly");
+    PROFILE_FN(fsPerfOpenExistingOnceWriteonly(g_szDir), g_nsTestRun, "RTFileOpen/Close/Writeonly");
+
+    /*
+     * Profile opening in the deep directory too.
+     */
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDeepDir(RT_STR_TUPLE("file1")),
+                                     RTFILE_O_CREATE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+    PROFILE_FN(fsPerfOpenExistingOnceReadonly(g_szDeepDir),  g_nsTestRun, "RTFileOpen/Close/deep/readonly");
+    PROFILE_FN(fsPerfOpenExistingOnceWriteonly(g_szDeepDir), g_nsTestRun, "RTFileOpen/Close/deep/writeonly");
+
+    /* Manytree: */
+    char szPath[RTPATH_MAX];
+    PROFILE_MANYTREE_FN(szPath, fsPerfOpenExistingOnceReadonly(szPath), 1, g_nsTestRun, "RTFileOpen/Close/manytree/readonly");
+}
+
+
+void fsPerfFStat(void)
+{
+    RTTestISub("fstat");
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file2")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTFSOBJINFO ObjInfo = {0};
+    PROFILE_FN(RTFileQueryInfo(hFile1, &ObjInfo,  RTFSOBJATTRADD_NOTHING), g_nsTestRun, "RTFileQueryInfo/NOTHING");
+    PROFILE_FN(RTFileQueryInfo(hFile1, &ObjInfo,  RTFSOBJATTRADD_UNIX),    g_nsTestRun, "RTFileQueryInfo/UNIX");
+
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+}
+
+
+void fsPerfFChMod(void)
+{
+    RTTestISub("fchmod");
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file4")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTFSOBJINFO ObjInfo = {0};
+    RTTESTI_CHECK_RC(RTFileQueryInfo(hFile1, &ObjInfo,  RTFSOBJATTRADD_NOTHING), VINF_SUCCESS);
+    RTFMODE const fEvenMode = (ObjInfo.Attr.fMode & ~RTFS_UNIX_ALL_ACCESS_PERMS) | RTFS_DOS_READONLY   | 0400;
+    RTFMODE const fOddMode  = (ObjInfo.Attr.fMode & ~(RTFS_UNIX_ALL_ACCESS_PERMS | RTFS_DOS_READONLY)) | 0640;
+    PROFILE_FN(RTFileSetMode(hFile1, iIteration & 1 ? fOddMode : fEvenMode), g_nsTestRun, "RTFileSetMode");
+
+    RTFileSetMode(hFile1, ObjInfo.Attr.fMode);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+}
+
+
+void fsPerfFUtimes(void)
+{
+    RTTestISub("futimes");
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file5")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTIMESPEC Time1;
+    RTTimeNow(&Time1);
+    RTTIMESPEC Time2 = Time1;
+    RTTimeSpecSubSeconds(&Time2, 3636);
+
+    RTFSOBJINFO ObjInfo0 = {0};
+    RTTESTI_CHECK_RC(RTFileQueryInfo(hFile1, &ObjInfo0,  RTFSOBJATTRADD_NOTHING), VINF_SUCCESS);
+
+    /* Modify modification time: */
+    RTTESTI_CHECK_RC(RTFileSetTimes(hFile1, NULL, &Time2, NULL, NULL), VINF_SUCCESS);
+    RTFSOBJINFO ObjInfo1 = {0};
+    RTTESTI_CHECK_RC(RTFileQueryInfo(hFile1, &ObjInfo1,  RTFSOBJATTRADD_NOTHING), VINF_SUCCESS);
+    RTTESTI_CHECK((RTTimeSpecGetSeconds(&ObjInfo1.ModificationTime) >> 2) == (RTTimeSpecGetSeconds(&Time2) >> 2));
+    char sz1[RTTIME_STR_LEN], sz2[RTTIME_STR_LEN]; /* Div by 1000 here for posix impl. using timeval. */
+    RTTESTI_CHECK_MSG(RTTimeSpecGetNano(&ObjInfo1.AccessTime) / 1000 == RTTimeSpecGetNano(&ObjInfo0.AccessTime) / 1000,
+                      ("%s, expected %s", RTTimeSpecToString(&ObjInfo1.AccessTime, sz1, sizeof(sz1)),
+                       RTTimeSpecToString(&ObjInfo0.AccessTime, sz2, sizeof(sz2))));
+
+    /* Modify access time: */
+    RTTESTI_CHECK_RC(RTFileSetTimes(hFile1, &Time1, NULL, NULL, NULL), VINF_SUCCESS);
+    RTFSOBJINFO ObjInfo2 = {0};
+    RTTESTI_CHECK_RC(RTFileQueryInfo(hFile1, &ObjInfo2,  RTFSOBJATTRADD_NOTHING), VINF_SUCCESS);
+    RTTESTI_CHECK((RTTimeSpecGetSeconds(&ObjInfo2.AccessTime) >> 2) == (RTTimeSpecGetSeconds(&Time1) >> 2));
+    RTTESTI_CHECK(RTTimeSpecGetNano(&ObjInfo2.ModificationTime) / 1000 == RTTimeSpecGetNano(&ObjInfo1.ModificationTime) / 1000);
+
+    /* Benchmark it: */
+    PROFILE_FN(RTFileSetTimes(hFile1, NULL, iIteration & 1 ? &Time1 : &Time2, NULL, NULL), g_nsTestRun, "RTFileSetTimes");
+
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+}
+
+
+void fsPerfStat(void)
+{
+    RTTestISub("stat");
+    RTFSOBJINFO ObjInfo;
+
+    /* Non-existing files. */
+    RTTESTI_CHECK_RC(RTPathQueryInfoEx(InEmptyDir(RT_STR_TUPLE("no-such-file")),
+                                       &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK), VERR_FILE_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTPathQueryInfoEx(InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file")),
+                                       &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK), FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTPathQueryInfoEx(InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file")),
+                                       &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK), VERR_PATH_NOT_FOUND);
+
+    /* Shallow: */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file3")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    PROFILE_FN(RTPathQueryInfoEx(g_szDir, &ObjInfo,  RTFSOBJATTRADD_NOTHING,  RTPATH_F_ON_LINK), g_nsTestRun,
+               "RTPathQueryInfoEx/NOTHING");
+    PROFILE_FN(RTPathQueryInfoEx(g_szDir, &ObjInfo,  RTFSOBJATTRADD_UNIX,     RTPATH_F_ON_LINK), g_nsTestRun,
+               "RTPathQueryInfoEx/UNIX");
+
+
+    /* Deep: */
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDeepDir(RT_STR_TUPLE("file3")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    PROFILE_FN(RTPathQueryInfoEx(g_szDeepDir, &ObjInfo,  RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK), g_nsTestRun,
+               "RTPathQueryInfoEx/deep/NOTHING");
+    PROFILE_FN(RTPathQueryInfoEx(g_szDeepDir, &ObjInfo,  RTFSOBJATTRADD_UNIX, RTPATH_F_ON_LINK), g_nsTestRun,
+               "RTPathQueryInfoEx/deep/UNIX");
+
+    /* Manytree: */
+    char szPath[RTPATH_MAX];
+    PROFILE_MANYTREE_FN(szPath, RTPathQueryInfoEx(szPath, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK),
+                        1, g_nsTestRun, "RTPathQueryInfoEx/manytree/NOTHING");
+    PROFILE_MANYTREE_FN(szPath, RTPathQueryInfoEx(szPath, &ObjInfo, RTFSOBJATTRADD_UNIX, RTPATH_F_ON_LINK),
+                        1, g_nsTestRun, "RTPathQueryInfoEx/manytree/UNIX");
+}
+
+
+void fsPerfChmod(void)
+{
+    RTTestISub("chmod");
+
+    /* Non-existing files. */
+    RTTESTI_CHECK_RC(RTPathSetMode(InEmptyDir(RT_STR_TUPLE("no-such-file")), 0665),
+                     VERR_FILE_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTPathSetMode(InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file")), 0665),
+                     FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTPathSetMode(InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file")), 0665), VERR_PATH_NOT_FOUND);
+
+    /* Shallow: */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file14")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    RTFSOBJINFO ObjInfo;
+    RTTESTI_CHECK_RC(RTPathQueryInfoEx(g_szDir, &ObjInfo,  RTFSOBJATTRADD_NOTHING,  RTPATH_F_ON_LINK), VINF_SUCCESS);
+    RTFMODE const fEvenMode = (ObjInfo.Attr.fMode & ~RTFS_UNIX_ALL_ACCESS_PERMS) | RTFS_DOS_READONLY   | 0400;
+    RTFMODE const fOddMode  = (ObjInfo.Attr.fMode & ~(RTFS_UNIX_ALL_ACCESS_PERMS | RTFS_DOS_READONLY)) | 0640;
+    PROFILE_FN(RTPathSetMode(g_szDir, iIteration & 1 ? fOddMode : fEvenMode), g_nsTestRun, "RTPathSetMode");
+    RTPathSetMode(g_szDir, ObjInfo.Attr.fMode);
+
+    /* Deep: */
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDeepDir(RT_STR_TUPLE("file14")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    PROFILE_FN(RTPathSetMode(g_szDeepDir, iIteration & 1 ? fOddMode : fEvenMode), g_nsTestRun, "RTPathSetMode/deep");
+    RTPathSetMode(g_szDeepDir, ObjInfo.Attr.fMode);
+
+    /* Manytree: */
+    char szPath[RTPATH_MAX];
+    PROFILE_MANYTREE_FN(szPath, RTPathSetMode(szPath, iIteration & 1 ? fOddMode : fEvenMode), 1, g_nsTestRun,
+                        "RTPathSetMode/manytree");
+    DO_MANYTREE_FN(szPath, RTPathSetMode(szPath, ObjInfo.Attr.fMode));
+}
+
+
+void fsPerfUtimes(void)
+{
+    RTTestISub("utimes");
+
+    RTTIMESPEC Time1;
+    RTTimeNow(&Time1);
+    RTTIMESPEC Time2 = Time1;
+    RTTimeSpecSubSeconds(&Time2, 3636);
+
+    /* Non-existing files. */
+    RTTESTI_CHECK_RC(RTPathSetTimesEx(InEmptyDir(RT_STR_TUPLE("no-such-file")), NULL, &Time1, NULL, NULL, RTPATH_F_ON_LINK),
+                     VERR_FILE_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTPathSetTimesEx(InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file")),
+                                      NULL, &Time1, NULL, NULL, RTPATH_F_ON_LINK),
+                     FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTPathSetTimesEx(InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file")),
+                                      NULL, &Time1, NULL, NULL, RTPATH_F_ON_LINK),
+                     VERR_PATH_NOT_FOUND);
+
+    /* Shallow: */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file15")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    RTFSOBJINFO ObjInfo0 = {0};
+    RTTESTI_CHECK_RC(RTPathQueryInfoEx(g_szDir, &ObjInfo0,  RTFSOBJATTRADD_NOTHING,  RTPATH_F_ON_LINK), VINF_SUCCESS);
+
+    /* Modify modification time: */
+    RTTESTI_CHECK_RC(RTPathSetTimesEx(g_szDir, NULL, &Time2, NULL, NULL, RTPATH_F_ON_LINK), VINF_SUCCESS);
+    RTFSOBJINFO ObjInfo1;
+    RTTESTI_CHECK_RC(RTPathQueryInfoEx(g_szDir, &ObjInfo1,  RTFSOBJATTRADD_NOTHING,  RTPATH_F_ON_LINK), VINF_SUCCESS);
+    RTTESTI_CHECK((RTTimeSpecGetSeconds(&ObjInfo1.ModificationTime) >> 2) == (RTTimeSpecGetSeconds(&Time2) >> 2));
+    RTTESTI_CHECK(RTTimeSpecGetNano(&ObjInfo1.AccessTime) / 1000 == RTTimeSpecGetNano(&ObjInfo0.AccessTime) / 1000 /* posix timeval */);
+
+    /* Modify access time: */
+    RTTESTI_CHECK_RC(RTPathSetTimesEx(g_szDir, &Time1, NULL, NULL, NULL, RTPATH_F_ON_LINK), VINF_SUCCESS);
+    RTFSOBJINFO ObjInfo2 = {0};
+    RTTESTI_CHECK_RC(RTPathQueryInfoEx(g_szDir, &ObjInfo2,  RTFSOBJATTRADD_NOTHING,  RTPATH_F_ON_LINK), VINF_SUCCESS);
+    RTTESTI_CHECK((RTTimeSpecGetSeconds(&ObjInfo2.AccessTime) >> 2) == (RTTimeSpecGetSeconds(&Time1) >> 2));
+    RTTESTI_CHECK(RTTimeSpecGetNano(&ObjInfo2.ModificationTime) / 1000 == RTTimeSpecGetNano(&ObjInfo1.ModificationTime) / 1000 /* posix timeval */);
+
+    /* Profile shallow: */
+    PROFILE_FN(RTPathSetTimesEx(g_szDir, iIteration & 1 ? &Time1 : &Time2, iIteration & 1 ? &Time2 : &Time1,
+                                NULL, NULL, RTPATH_F_ON_LINK),
+               g_nsTestRun, "RTPathSetTimesEx");
+
+    /* Deep: */
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDeepDir(RT_STR_TUPLE("file15")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    PROFILE_FN(RTPathSetTimesEx(g_szDeepDir, iIteration & 1 ? &Time1 : &Time2, iIteration & 1 ? &Time2 : &Time1,
+                                NULL, NULL, RTPATH_F_ON_LINK),
+               g_nsTestRun, "RTPathSetTimesEx/deep");
+
+    /* Manytree: */
+    char szPath[RTPATH_MAX];
+    PROFILE_MANYTREE_FN(szPath, RTPathSetTimesEx(szPath, iIteration & 1 ? &Time1 : &Time2, iIteration & 1 ? &Time2 : &Time1,
+                                                 NULL, NULL, RTPATH_F_ON_LINK),
+                        1, g_nsTestRun, "RTPathSetTimesEx/manytree");
+}
+
+
+DECL_FORCE_INLINE(int) fsPerfRenameMany(const char *pszFile, uint32_t iIteration)
+{
+    char szRenamed[RTPATH_MAX];
+    strcat(strcpy(szRenamed, pszFile), "-renamed");
+    if (!(iIteration & 1))
+        return RTPathRename(pszFile, szRenamed, 0);
+    return RTPathRename(szRenamed, pszFile, 0);
+}
+
+
+void fsPerfRename(void)
+{
+    RTTestISub("rename");
+    char szPath[RTPATH_MAX];
+
+    /* Non-existing files. */
+    strcpy(szPath, InEmptyDir(RT_STR_TUPLE("other-no-such-file")));
+    RTTESTI_CHECK_RC(RTPathRename(InEmptyDir(RT_STR_TUPLE("no-such-file")), szPath, 0), VERR_FILE_NOT_FOUND);
+    strcpy(szPath, InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "other-no-such-file")));
+    RTTESTI_CHECK_RC(RTPathRename(InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file")), szPath, 0),
+                     FSPERF_VERR_PATH_NOT_FOUND);
+    strcpy(szPath, InEmptyDir(RT_STR_TUPLE("other-no-such-file")));
+    RTTESTI_CHECK_RC(RTPathRename(InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file")), szPath, 0), VERR_PATH_NOT_FOUND);
+
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file16")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+    strcat(strcpy(szPath, g_szDir), "-no-such-dir" RTPATH_SLASH_STR "file16");
+    RTTESTI_CHECK_RC(RTPathRename(szPath, g_szDir, 0), FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTPathRename(g_szDir, szPath, 0), FSPERF_VERR_PATH_NOT_FOUND);
+
+    /* Shallow: */
+    strcat(strcpy(szPath, g_szDir), "-other");
+    PROFILE_FN(RTPathRename(iIteration & 1 ? szPath : g_szDir, iIteration & 1 ? g_szDir : szPath, 0), g_nsTestRun, "RTPathRename");
+
+    /* Deep: */
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDeepDir(RT_STR_TUPLE("file15")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+
+    strcat(strcpy(szPath, g_szDeepDir), "-other");
+    PROFILE_FN(RTPathRename(iIteration & 1 ? szPath : g_szDeepDir, iIteration & 1 ? g_szDeepDir : szPath, 0),
+               g_nsTestRun, "RTPathRename/deep");
+
+    /* Manytree: */
+    PROFILE_MANYTREE_FN(szPath, fsPerfRenameMany(szPath, iIteration), 2, g_nsTestRun, "RTPathRename/manytree");
+}
+
+
+DECL_FORCE_INLINE(int) fsPerfEnumEmpty(void)
+{
+    RTDIR hDir;
+    g_szEmptyDir[g_cchEmptyDir] = '\0';
+    RTTESTI_CHECK_RC_RET(RTDirOpen(&hDir, g_szEmptyDir), VINF_SUCCESS, rcCheck);
+
+    RTDIRENTRY Entry;
+    RTTESTI_CHECK_RC(RTDirRead(hDir, &Entry, NULL), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTDirRead(hDir, &Entry, NULL), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTDirRead(hDir, &Entry, NULL), VERR_NO_MORE_FILES);
+
+    RTTESTI_CHECK_RC(RTDirClose(hDir), VINF_SUCCESS);
+    return VINF_SUCCESS;
+}
+
+
+DECL_FORCE_INLINE(int) fsPerfEnumManyFiles(void)
+{
+    RTDIR hDir;
+    RTTESTI_CHECK_RC_RET(RTDirOpen(&hDir, InDir(RT_STR_TUPLE("manyfiles"))), VINF_SUCCESS, rcCheck);
+    uint32_t cLeft = g_cManyFiles + 2;
+    for (;;)
+    {
+        RTDIRENTRY Entry;
+        if (cLeft > 0)
+            RTTESTI_CHECK_RC_BREAK(RTDirRead(hDir, &Entry, NULL), VINF_SUCCESS);
+        else
+        {
+            RTTESTI_CHECK_RC(RTDirRead(hDir, &Entry, NULL), VERR_NO_MORE_FILES);
+            break;
+        }
+        cLeft--;
+    }
+    RTTESTI_CHECK_RC(RTDirClose(hDir), VINF_SUCCESS);
+    return VINF_SUCCESS;
+}
+
+
+void vsPerfDirEnum(void)
+{
+    RTTestISub("dir enum");
+    RTDIR hDir;
+
+    /* Non-existing files. */
+    RTTESTI_CHECK_RC(RTDirOpen(&hDir, InEmptyDir(RT_STR_TUPLE("no-such-file"))), VERR_FILE_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTDirOpen(&hDir, InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file"))), FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTDirOpen(&hDir, InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file"))), VERR_PATH_NOT_FOUND);
+
+    /*
+     * The empty directory.
+     */
+    g_szEmptyDir[g_cchEmptyDir] = '\0';
+    RTTESTI_CHECK_RC_RETV(RTDirOpen(&hDir, g_szEmptyDir), VINF_SUCCESS);
+
+    uint32_t   fDots = 0;
+    RTDIRENTRY Entry;
+    RTTESTI_CHECK_RC(RTDirRead(hDir, &Entry, NULL), VINF_SUCCESS);
+    RTTESTI_CHECK(RTDirEntryIsStdDotLink(&Entry));
+    fDots |= RT_BIT_32(Entry.cbName - 1);
+
+    RTTESTI_CHECK_RC(RTDirRead(hDir, &Entry, NULL), VINF_SUCCESS);
+    RTTESTI_CHECK(RTDirEntryIsStdDotLink(&Entry));
+    fDots |= RT_BIT_32(Entry.cbName - 1);
+    RTTESTI_CHECK(fDots == 3);
+
+    RTTESTI_CHECK_RC(RTDirRead(hDir, &Entry, NULL), VERR_NO_MORE_FILES);
+
+    RTTESTI_CHECK_RC(RTDirClose(hDir), VINF_SUCCESS);
+
+    /*
+     * The directory with many files in it.
+     */
+    if (g_fManyFiles)
+    {
+        fDots = 0;
+        uint32_t const cBitmap  = RT_ALIGN_32(g_cManyFiles, 64);
+        void          *pvBitmap = alloca(cBitmap / 8);
+        RT_BZERO(pvBitmap, cBitmap / 8);
+        for (uint32_t i = g_cManyFiles; i < cBitmap; i++)
+            ASMBitSet(pvBitmap, i);
+
+        uint32_t cFiles = 0;
+        RTTESTI_CHECK_RC_RETV(RTDirOpen(&hDir, InDir(RT_STR_TUPLE("manyfiles"))), VINF_SUCCESS);
+        for (;;)
+        {
+            int rc = RTDirRead(hDir, &Entry, NULL);
+            if (rc == VINF_SUCCESS)
+            {
+                if (Entry.szName[0] == '.')
+                {
+                    if (Entry.szName[1] == '.')
+                    {
+                        RTTESTI_CHECK(!(fDots & 2));
+                        fDots |= 2;
+                    }
+                    else
+                    {
+                        RTTESTI_CHECK(Entry.szName[1] == '\0');
+                        RTTESTI_CHECK(!(fDots & 1));
+                        fDots |= 1;
+                    }
+                }
+                else
+                {
+                    uint32_t iFile = UINT32_MAX;
+                    RTTESTI_CHECK_RC(RTStrToUInt32Full(Entry.szName, 10, &iFile), VINF_SUCCESS);
+                    if (   iFile < g_cManyFiles
+                        && !ASMBitTest(pvBitmap, iFile))
+                    {
+                        ASMBitSet(pvBitmap, iFile);
+                        cFiles++;
+                    }
+                    else
+                        RTTestFailed(g_hTest, "line %u: iFile=%u g_cManyFiles=%u\n", __LINE__, iFile, g_cManyFiles);
+                }
+            }
+            else if (rc == VERR_NO_MORE_FILES)
+                break;
+            else
+            {
+                RTTestFailed(g_hTest, "RTDirRead failed enumerating manyfiles: %Rrc\n", rc);
+                RTDirClose(hDir);
+                return;
+            }
+        }
+        RTTESTI_CHECK_RC(RTDirClose(hDir), VINF_SUCCESS);
+        RTTESTI_CHECK(fDots == 3);
+        RTTESTI_CHECK(cFiles == g_cManyFiles);
+        RTTESTI_CHECK(ASMMemIsAllU8(pvBitmap, cBitmap / 8, 0xff));
+    }
+
+    /*
+     * Profile.
+     */
+    PROFILE_FN(fsPerfEnumEmpty(),g_nsTestRun, "RTDirOpen/Read/Close empty");
+    if (g_fManyFiles)
+        PROFILE_FN(fsPerfEnumManyFiles(), g_nsTestRun, "RTDirOpen/Read/Close manyfiles");
+}
+
+
+void fsPerfMkRmDir(void)
+{
+    RTTestISub("mkdir/rmdir");
+
+    /* Non-existing directories: */
+    RTTESTI_CHECK_RC(RTDirRemove(InEmptyDir(RT_STR_TUPLE("no-such-dir"))), VERR_FILE_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTDirRemove(InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file"))), FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTDirRemove(InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file"))), VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTDirCreate(InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file")), 0755, 0), FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTDirCreate(InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file")), 0755, 0), VERR_PATH_NOT_FOUND);
+
+    /** @todo check what happens if non-final path component isn't a directory. unix
+     *        should return ENOTDIR and IPRT translates that to VERR_PATH_NOT_FOUND.
+     *        Curious what happens on windows. */
+
+    /* Already existing directories and files: */
+    RTTESTI_CHECK_RC(RTDirCreate(InEmptyDir(RT_STR_TUPLE(".")), 0755, 0), VERR_ALREADY_EXISTS);
+    RTTESTI_CHECK_RC(RTDirCreate(InEmptyDir(RT_STR_TUPLE("..")), 0755, 0), VERR_ALREADY_EXISTS);
+
+    /* Remove directory with subdirectories: */
+#if defined(RT_OS_WINDOWS)
+    RTTESTI_CHECK_RC(RTDirRemove(InDir(RT_STR_TUPLE("."))), VERR_DIR_NOT_EMPTY);
+#else
+    RTTESTI_CHECK_RC(RTDirRemove(InDir(RT_STR_TUPLE("."))), VERR_INVALID_PARAMETER); /* EINVAL for '.' */
+#endif
+#if defined(RT_OS_WINDOWS)
+    RTTESTI_CHECK_RC(RTDirRemove(InDir(RT_STR_TUPLE(".."))), VERR_SHARING_VIOLATION); /* weird */
+#else
+    RTTESTI_CHECK_RC(RTDirRemove(InDir(RT_STR_TUPLE(".."))), VERR_DIR_NOT_EMPTY);
+#endif
+    RTTESTI_CHECK_RC(RTDirRemove(InDir(RT_STR_TUPLE(""))), VERR_DIR_NOT_EMPTY);
+
+    /* Create a directory and remove it: */
+    RTTESTI_CHECK_RC(RTDirCreate(InDir(RT_STR_TUPLE("subdir-1")), 0755, 0), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTDirRemove(g_szDir), VINF_SUCCESS);
+
+    /* Create a file and try remove it or create a directory with the same name: */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file18")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTDirRemove(g_szDir), VERR_NOT_A_DIRECTORY);
+    RTTESTI_CHECK_RC(RTDirCreate(g_szDir, 0755, 0), VERR_ALREADY_EXISTS);
+    RTTESTI_CHECK_RC(RTDirCreate(InDir(RT_STR_TUPLE("file18" RTPATH_SLASH_STR "subdir")), 0755, 0), VERR_PATH_NOT_FOUND);
+
+    /*
+     * Profile alternately creating and removing a bunch of directories.
+     */
+    RTTESTI_CHECK_RC_RETV(RTDirCreate(InDir(RT_STR_TUPLE("subdir-2")), 0755, 0), VINF_SUCCESS);
+    size_t cchDir = strlen(g_szDir);
+    g_szDir[cchDir++] = RTPATH_SLASH;
+    g_szDir[cchDir++] = 's';
+
+    uint32_t cCreated = 0;
+    uint64_t nsCreate = 0;
+    uint64_t nsRemove = 0;
+    for (;;)
+    {
+        /* Create a bunch: */
+        uint64_t nsStart = RTTimeNanoTS();
+        for (uint32_t i = 0; i < 998; i++)
+        {
+            RTStrFormatU32(&g_szDir[cchDir], sizeof(g_szDir) - cchDir, i, 10, 3, 3, RTSTR_F_ZEROPAD);
+            RTTESTI_CHECK_RC_RETV(RTDirCreate(g_szDir, 0755, 0), VINF_SUCCESS);
+        }
+        nsCreate += RTTimeNanoTS() - nsStart;
+        cCreated += 998;
+
+        /* Remove the bunch: */
+        nsStart = RTTimeNanoTS();
+        for (uint32_t i = 0; i < 998; i++)
+        {
+            RTStrFormatU32(&g_szDir[cchDir], sizeof(g_szDir) - cchDir, i, 10, 3, 3, RTSTR_F_ZEROPAD);
+            RTTESTI_CHECK_RC_RETV(RTDirRemove(g_szDir), VINF_SUCCESS);
+        }
+        nsRemove = RTTimeNanoTS() - nsStart;
+
+        /* Check if we got time for another round: */
+        if (   (   nsRemove >= g_nsTestRun
+                && nsCreate >= g_nsTestRun)
+            || nsCreate + nsRemove >= g_nsTestRun * 3)
+            break;
+    }
+    RTTestIValue("RTDirCreate", nsCreate / cCreated, RTTESTUNIT_NS_PER_OCCURRENCE);
+    RTTestIValue("RTDirRemove", nsRemove / cCreated, RTTESTUNIT_NS_PER_OCCURRENCE);
+}
+
+
+void fsPerfStatVfs(void)
+{
+    RTTestISub("statvfs");
+
+    g_szEmptyDir[g_cchEmptyDir] = '\0';
+    RTFOFF   cbTotal;
+    RTFOFF   cbFree;
+    uint32_t cbBlock;
+    uint32_t cbSector;
+    RTTESTI_CHECK_RC(RTFsQuerySizes(g_szEmptyDir, &cbTotal, &cbFree, &cbBlock, &cbSector), VINF_SUCCESS);
+
+    uint32_t uSerial;
+    RTTESTI_CHECK_RC(RTFsQuerySerial(g_szEmptyDir, &uSerial), VINF_SUCCESS);
+
+    RTFSPROPERTIES Props;
+    RTTESTI_CHECK_RC(RTFsQueryProperties(g_szEmptyDir, &Props), VINF_SUCCESS);
+
+    RTFSTYPE enmType;
+    RTTESTI_CHECK_RC(RTFsQueryType(g_szEmptyDir, &enmType), VINF_SUCCESS);
+
+}
+
+
+void fsPerfRm(void)
+{
+    RTTestISub("rm");
+
+    /* Non-existing files. */
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE("no-such-file"))), VERR_FILE_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE("no-such-dir" RTPATH_SLASH_STR "no-such-file"))), FSPERF_VERR_PATH_NOT_FOUND);
+    RTTESTI_CHECK_RC(RTFileDelete(InDir(RT_STR_TUPLE("known-file" RTPATH_SLASH_STR "no-such-file"))), VERR_PATH_NOT_FOUND);
+
+    /* Directories: */
+#if defined(RT_OS_WINDOWS)
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE("."))),  VERR_ACCESS_DENIED);
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE(".."))), VERR_ACCESS_DENIED);
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE(""))),   VERR_ACCESS_DENIED);
+#else
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE("."))),  VERR_IS_A_DIRECTORY);
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE(".."))), VERR_IS_A_DIRECTORY);
+    RTTESTI_CHECK_RC(RTFileDelete(InEmptyDir(RT_STR_TUPLE(""))),   VERR_IS_A_DIRECTORY);
+#endif
+
+    /* Shallow: */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file19")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_WRITE), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileDelete(g_szDir), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileDelete(g_szDir), VERR_FILE_NOT_FOUND);
+
+    if (g_fManyFiles)
+    {
+        /*
+         * Profile the deletion of the manyfiles content.
+         */
+        {
+            InDir(RT_STR_TUPLE("manyfiles" RTPATH_SLASH_STR));
+            size_t const offFilename = strlen(g_szDir);
+            fsPerfYield();
+            uint64_t const nsStart = RTTimeNanoTS();
+            for (uint32_t i = 0; i < g_cManyFiles; i++)
+            {
+                RTStrFormatU32(&g_szDir[offFilename], sizeof(g_szDir) - offFilename, i, 10, 5, 5, RTSTR_F_ZEROPAD);
+                RTTESTI_CHECK_RC_RETV(RTFileDelete(g_szDir), VINF_SUCCESS);
+            }
+            uint64_t const cNsElapsed = RTTimeNanoTS() - nsStart;
+            RTTestIValueF(cNsElapsed, RTTESTUNIT_NS, "Deleted %u empty files from a single directory", g_cManyFiles);
+            RTTestIValueF(cNsElapsed / g_cManyFiles, RTTESTUNIT_NS_PER_OCCURRENCE, "Delete file (single dir)");
+        }
+
+        /*
+         * Ditto for the manytree.
+         */
+        {
+            char szPath[RTPATH_MAX];
+            uint64_t const nsStart = RTTimeNanoTS();
+            DO_MANYTREE_FN(szPath, RTTESTI_CHECK_RC_RETV(RTFileDelete(szPath), VINF_SUCCESS));
+            uint64_t const cNsElapsed = RTTimeNanoTS() - nsStart;
+            RTTestIValueF(cNsElapsed, RTTESTUNIT_NS, "Deleted %u empty files in tree", g_cManyTreeFiles);
+            RTTestIValueF(cNsElapsed / g_cManyTreeFiles, RTTESTUNIT_NS_PER_OCCURRENCE, "Delete file (tree)");
+        }
+    }
+}
+
+
+void fsPerfChSize(void)
+{
+    RTTestISub("chsize");
+
+    /*
+     * We need some free space to perform this test.
+     */
+    g_szDir[g_cchDir] = '\0';
+    RTFOFF cbFree = 0;
+    RTTESTI_CHECK_RC_RETV(RTFsQuerySizes(g_szDir, NULL, &cbFree, NULL, NULL), VINF_SUCCESS);
+    if (cbFree < _1M)
+    {
+        RTTestSkipped(g_hTest, "Insufficent free space: %'RU64 bytes, requires >= 1MB", cbFree);
+        return;
+    }
+
+    /*
+     * Create a file and play around with it's size.
+     * We let the current file position follow the end position as we make changes.
+     */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file20")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_READWRITE), VINF_SUCCESS);
+    uint64_t cbFile = UINT64_MAX;
+    RTTESTI_CHECK_RC(RTFileGetSize(hFile1, &cbFile), VINF_SUCCESS);
+    RTTESTI_CHECK(cbFile == 0);
+
+    uint8_t abBuf[4096];
+    static uint64_t const s_acbChanges[] =
+    {
+        1023, 1024, 1024, 1025, 8192, 11111, _1M, _8M, _8M,
+        _4M, _2M + 1, _1M - 1, 65537, 65536, 32768, 8000, 7999, 7998, 1024, 1, 0
+    };
+    uint64_t cbOld = 0;
+    for (unsigned i = 0; i < RT_ELEMENTS(s_acbChanges); i++)
+    {
+        uint64_t cbNew = s_acbChanges[i];
+        if (cbNew + _64K >= (uint64_t)cbFree)
+            continue;
+
+        RTTESTI_CHECK_RC(RTFileSetSize(hFile1, cbNew), VINF_SUCCESS);
+        RTTESTI_CHECK_RC(RTFileGetSize(hFile1, &cbFile), VINF_SUCCESS);
+        RTTESTI_CHECK_MSG(cbFile == cbNew, ("cbFile=%#RX64 cbNew=%#RX64\n", cbFile, cbNew));
+
+        if (cbNew > cbOld)
+        {
+            /* Check that the extension is all zeroed: */
+            uint64_t cbLeft = cbNew - cbOld;
+            while (cbLeft > 0)
+            {
+                memset(abBuf, 0xff, sizeof(abBuf));
+                size_t cbToRead = sizeof(abBuf);
+                if (cbToRead > cbLeft)
+                    cbToRead = (size_t)cbLeft;
+                RTTESTI_CHECK_RC(RTFileRead(hFile1, abBuf, cbToRead, NULL), VINF_SUCCESS);
+                RTTESTI_CHECK(ASMMemIsZero(abBuf, cbToRead));
+                cbLeft -= cbToRead;
+            }
+        }
+        else
+        {
+            /* Check that reading fails with EOF because current position is now beyond the end: */
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, abBuf, 1, NULL), VERR_EOF);
+
+            /* Keep current position at the end of the file: */
+            RTTESTI_CHECK_RC(RTFileSeek(hFile1, cbNew, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+        }
+        cbOld = cbNew;
+    }
+
+    /*
+     * Profile just the file setting operation itself, keeping the changes within
+     * an allocation unit to avoid needing to adjust the actual (host) FS allocation.
+     * ASSUMES allocation unit >= 512 and power of two.
+     */
+    RTTESTI_CHECK_RC(RTFileSetSize(hFile1, _64K), VINF_SUCCESS);
+    PROFILE_FN(RTFileSetSize(hFile1, _64K - (iIteration & 255) - 128), g_nsTestRun, "RTFileSetSize/noalloc");
+
+    RTTESTI_CHECK_RC(RTFileSetSize(hFile1, 0), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileDelete(g_szDir), VINF_SUCCESS);
+}
+
+
+int fsPerfIoPrepFile(RTFILE hFile1, uint64_t cbFile, uint8_t **ppbFree)
+{
+    /*
+     * Seek to the end - 4K and write the last 4K.
+     * This should have the effect of filling the whole file with zeros.
+     */
+    RTTESTI_CHECK_RC_RET(RTFileSeek(hFile1, cbFile - _4K, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS, rcCheck);
+    RTTESTI_CHECK_RC_RET(RTFileWrite(hFile1, g_abRTZero4K, _4K, NULL), VINF_SUCCESS, rcCheck);
+
+    /*
+     * Check that the space we searched across actually is zero filled.
+     */
+    RTTESTI_CHECK_RC_RET(RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS, rcCheck);
+    size_t   cbBuf = _1M;
+    uint8_t *pbBuf = *ppbFree = (uint8_t *)RTMemAlloc(cbBuf);
+    RTTESTI_CHECK_RET(pbBuf != NULL, VERR_NO_MEMORY);
+    uint64_t cbLeft = cbFile;
+    while (cbLeft > 0)
+    {
+        size_t cbToRead = cbBuf;
+        if (cbToRead > cbLeft)
+            cbToRead = (size_t)cbLeft;
+        pbBuf[cbToRead] = 0xff;
+
+        RTTESTI_CHECK_RC_RET(RTFileRead(hFile1, pbBuf, cbToRead, NULL), VINF_SUCCESS, rcCheck);
+        RTTESTI_CHECK_RET(ASMMemIsZero(pbBuf, cbToRead), VERR_MISMATCH);
+
+        cbLeft -= cbToRead;
+    }
+
+    /*
+     * Fill the file with 0xf6 and insert offset markers with 1KB intervals.
+     */
+    RTTESTI_CHECK_RC_RET(RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS, rcCheck);
+    memset(pbBuf, 0xf6, cbBuf);
+    cbLeft = cbFile;
+    uint64_t off = 0;
+    while (cbLeft > 0)
+    {
+        Assert(!(off   & (_1K - 1)));
+        Assert(!(cbBuf & (_1K - 1)));
+        for (size_t offBuf = 0; offBuf < cbBuf; offBuf += _1K, off += _1K)
+            *(uint64_t *)&pbBuf[offBuf] = off;
+
+        size_t cbToWrite = cbBuf;
+        if (cbToWrite > cbLeft)
+            cbToWrite = (size_t)cbLeft;
+
+        RTTESTI_CHECK_RC_RET(RTFileWrite(hFile1, pbBuf, cbToWrite, NULL), VINF_SUCCESS, rcCheck);
+
+        cbLeft -= cbToWrite;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Checks the content read from the file fsPerfIoPrepFile() prepared.
+ */
+bool fsPerfCheckReadBuf(unsigned uLineNo, uint64_t off, uint8_t const *pbBuf, size_t cbBuf, uint8_t bFiller = 0xf6)
+{
+    uint32_t cMismatches = 0;
+    size_t   offBuf      = 0;
+    uint32_t offBlock    = (uint32_t)(off & (_1K - 1));
+    while (offBuf < cbBuf)
+    {
+        /*
+         * Check the offset marker:
+         */
+        if (offBlock < sizeof(uint64_t))
+        {
+            RTUINT64U uMarker;
+            uMarker.u = off + offBuf - offBlock;
+            unsigned offMarker = offBlock & (sizeof(uint64_t) - 1);
+            while (offMarker < sizeof(uint64_t) && offBuf < cbBuf)
+            {
+                if (uMarker.au8[offMarker] != pbBuf[offBuf])
+                {
+                    RTTestIFailed("%u: Mismatch at buffer/file offset %#zx/%#RX64: %#x, expected %#x",
+                                  uLineNo, offBuf, off + offBuf, pbBuf[offBuf], uMarker.au8[offMarker]);
+                    if (cMismatches++ > 32)
+                        return false;
+                }
+                offMarker++;
+                offBuf++;
+            }
+            offBlock = sizeof(uint64_t);
+        }
+
+        /*
+         * Check the filling:
+         */
+        size_t cbFilling = RT_MIN(_1K - offBlock, cbBuf - offBuf);
+        if (   cbFilling == 0
+            || ASMMemIsAllU8(&pbBuf[offBuf], cbFilling, bFiller))
+            offBuf += cbFilling;
+        else
+        {
+            /* Some mismatch, locate it/them: */
+            while (cbFilling > 0 && offBuf < cbBuf)
+            {
+                if (pbBuf[offBuf] != bFiller)
+                {
+                    RTTestIFailed("%u: Mismatch at buffer/file offset %#zx/%#RX64: %#x, expected %#04x",
+                                  uLineNo, offBuf, off + offBuf, pbBuf[offBuf], bFiller);
+                    if (cMismatches++ > 32)
+                        return false;
+                }
+                offBuf++;
+                cbFilling--;
+            }
+        }
+        offBlock = 0;
+    }
+    return cMismatches == 0;
+}
+
+
+/**
+ * Sets up write buffer with offset markers and fillers.
+ */
+void fsPerfFillWriteBuf(uint64_t off, uint8_t *pbBuf, size_t cbBuf, uint8_t bFiller = 0xf6)
+{
+    uint32_t offBlock = (uint32_t)(off & (_1K - 1));
+    while (cbBuf > 0)
+    {
+        /* The marker. */
+        if (offBlock < sizeof(uint64_t))
+        {
+            RTUINT64U uMarker;
+            uMarker.u = off + offBlock;
+            if (cbBuf > sizeof(uMarker) - offBlock)
+            {
+                memcpy(pbBuf, &uMarker.au8[offBlock], sizeof(uMarker) - offBlock);
+                pbBuf += sizeof(uMarker) - offBlock;
+                cbBuf -= sizeof(uMarker) - offBlock;
+                off   += sizeof(uMarker) - offBlock;
+            }
+            else
+            {
+                memcpy(pbBuf, &uMarker.au8[offBlock], cbBuf);
+                return;
+            }
+            offBlock = sizeof(uint64_t);
+        }
+
+        /* Do the filling. */
+        size_t cbFilling = RT_MIN(_1K - offBlock, cbBuf);
+        memset(pbBuf, bFiller, cbFilling);
+        pbBuf += cbFilling;
+        cbBuf -= cbFilling;
+        off   += cbFilling;
+
+        offBlock = 0;
+    }
+}
+
+
+
+void fsPerfIoSeek(RTFILE hFile1, uint64_t cbFile)
+{
+    /*
+     * Do a bunch of search tests, most which are random.
+     */
+    struct
+    {
+        int         rc;
+        uint32_t    uMethod;
+        int64_t     offSeek;
+        uint64_t    offActual;
+
+    } aSeeks[9 + 64] =
+    {
+        { VINF_SUCCESS,         RTFILE_SEEK_BEGIN,    0,                        0 },
+        { VINF_SUCCESS,         RTFILE_SEEK_CURRENT,  0,                        0 },
+        { VINF_SUCCESS,         RTFILE_SEEK_END,      0,                        cbFile },
+        { VINF_SUCCESS,         RTFILE_SEEK_CURRENT,  -4096,                    cbFile - 4096 },
+        { VINF_SUCCESS,         RTFILE_SEEK_CURRENT,  4096 - (int64_t)cbFile,   0 },
+        { VINF_SUCCESS,         RTFILE_SEEK_END,      -(int64_t)cbFile/2,       cbFile / 2 + (cbFile & 1) },
+        { VINF_SUCCESS,         RTFILE_SEEK_CURRENT,  -(int64_t)cbFile/2,       0 },
+#if defined(RT_OS_WINDOWS)
+        { VERR_NEGATIVE_SEEK,   RTFILE_SEEK_CURRENT,  -1,                       0 },
+#else
+        { VERR_INVALID_PARAMETER, RTFILE_SEEK_CURRENT, -1,                      0 },
+#endif
+        { VINF_SUCCESS,         RTFILE_SEEK_CURRENT,  0,                        0 },
+    };
+
+    uint64_t offActual = 0;
+    for (unsigned i = 9; i < RT_ELEMENTS(aSeeks); i++)
+    {
+        switch (RTRandU32Ex(RTFILE_SEEK_BEGIN, RTFILE_SEEK_END))
+        {
+            default: AssertFailedBreak();
+            case RTFILE_SEEK_BEGIN:
+                aSeeks[i].uMethod   = RTFILE_SEEK_BEGIN;
+                aSeeks[i].rc        = VINF_SUCCESS;
+                aSeeks[i].offSeek   = RTRandU64Ex(0, cbFile + cbFile / 8);
+                aSeeks[i].offActual = offActual = aSeeks[i].offSeek;
+                break;
+
+            case RTFILE_SEEK_CURRENT:
+                aSeeks[i].uMethod   = RTFILE_SEEK_CURRENT;
+                aSeeks[i].rc        = VINF_SUCCESS;
+                aSeeks[i].offSeek   = (int64_t)RTRandU64Ex(0, cbFile + cbFile / 8) - (int64_t)offActual;
+                aSeeks[i].offActual = offActual += aSeeks[i].offSeek;
+                break;
+
+            case RTFILE_SEEK_END:
+                aSeeks[i].uMethod   = RTFILE_SEEK_END;
+                aSeeks[i].rc        = VINF_SUCCESS;
+                aSeeks[i].offSeek   = -(int64_t)RTRandU64Ex(0, cbFile);
+                aSeeks[i].offActual = offActual = cbFile + aSeeks[i].offSeek;
+                break;
+        }
+    }
+
+    for (unsigned iDoReadCheck = 0; iDoReadCheck < 2; iDoReadCheck++)
+    {
+        for (uint32_t i = 0; i < RT_ELEMENTS(aSeeks); i++)
+        {
+            offActual = UINT64_MAX;
+            int rc = RTFileSeek(hFile1, aSeeks[i].offSeek, aSeeks[i].uMethod, &offActual);
+            if (rc != aSeeks[i].rc)
+                RTTestIFailed("Seek #%u: Expected %Rrc, got %Rrc", i, aSeeks[i].rc, rc);
+            if (RT_SUCCESS(rc) && offActual != aSeeks[i].offActual)
+                RTTestIFailed("Seek #%u: offActual %#RX64, expected %#RX64", i, offActual, aSeeks[i].offActual);
+            if (RT_SUCCESS(rc))
+            {
+                uint64_t offTell = RTFileTell(hFile1);
+                if (offTell != offActual)
+                    RTTestIFailed("Seek #%u: offActual %#RX64, RTFileTell %#RX64", i, offActual, offTell);
+            }
+
+            if (RT_SUCCESS(rc) && offActual + _2K <= cbFile && iDoReadCheck)
+            {
+                uint8_t abBuf[_2K];
+                RTTESTI_CHECK_RC(rc = RTFileRead(hFile1, abBuf, sizeof(abBuf), NULL), VINF_SUCCESS);
+                if (RT_SUCCESS(rc))
+                {
+                    size_t offMarker = (size_t)(RT_ALIGN_64(offActual, _1K) - offActual);
+                    uint64_t uMarker = *(uint64_t *)&abBuf[offMarker]; /** @todo potentially unaligned access */
+                    if (uMarker != offActual + offMarker)
+                        RTTestIFailed("Seek #%u: Invalid marker value (@ %#RX64): %#RX64, expected %#RX64",
+                                      i, offActual, uMarker, offActual + offMarker);
+
+                    RTTESTI_CHECK_RC(RTFileSeek(hFile1, -(int64_t)sizeof(abBuf), RTFILE_SEEK_CURRENT, NULL), VINF_SUCCESS);
+                }
+            }
+        }
+    }
+
+
+    /*
+     * Profile seeking relative to the beginning of the file and relative
+     * to the end.  The latter might be more expensive in a SF context.
+     */
+    PROFILE_FN(RTFileSeek(hFile1, iIteration < cbFile ? iIteration : iIteration % cbFile, RTFILE_SEEK_BEGIN, NULL),
+               g_nsTestRun, "RTFileSeek/BEGIN");
+    PROFILE_FN(RTFileSeek(hFile1, iIteration < cbFile ? -(int64_t)iIteration : -(int64_t)(iIteration % cbFile), RTFILE_SEEK_END, NULL),
+               g_nsTestRun, "RTFileSeek/END");
+
+}
+
+
+/** For fsPerfIoRead and fsPerfIoWrite. */
+#define PROFILE_IO_FN(a_szOperation, a_fnCall) \
+    do \
+    { \
+        RTTESTI_CHECK_RC_RETV(RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS); \
+        uint64_t offActual = 0; \
+        uint32_t cSeeks    = 0; \
+        \
+        /* Estimate how many iterations we need to fill up the given timeslot: */ \
+        fsPerfYield(); \
+        uint64_t nsStart = RTTimeNanoTS(); \
+        uint64_t ns; \
+        do \
+            ns = RTTimeNanoTS(); \
+        while (ns == nsStart); \
+        nsStart = ns; \
+        \
+        uint64_t iIteration = 0; \
+        do \
+        { \
+            RTTESTI_CHECK_RC(a_fnCall, VINF_SUCCESS); \
+            iIteration++; \
+            ns = RTTimeNanoTS() - nsStart; \
+        } while (ns < RT_NS_10MS); \
+        ns /= iIteration; \
+        if (ns > g_nsPerNanoTSCall + 32) \
+            ns -= g_nsPerNanoTSCall; \
+        uint64_t cIterations = g_nsTestRun / ns; \
+        \
+        /* Do the actual profiling: */ \
+        cSeeks = 0; \
+        iIteration = 0; \
+        fsPerfYield(); \
+        nsStart = RTTimeNanoTS(); \
+        for (uint32_t iAdjust = 0; iAdjust < 4; iAdjust++) \
+        { \
+            for (; iIteration < cIterations; iIteration++)\
+                RTTESTI_CHECK_RC(a_fnCall, VINF_SUCCESS); \
+            ns = RTTimeNanoTS() - nsStart;\
+            if (ns >= g_nsTestRun - (g_nsTestRun / 10)) \
+                break; \
+            cIterations += cIterations / 4; \
+            if (cIterations & 1) \
+                cIterations++; \
+            nsStart += g_nsPerNanoTSCall; \
+        } \
+        RTTestIValueF(ns / iIteration, \
+                      RTTESTUNIT_NS_PER_OCCURRENCE, a_szOperation "/seq/%RU32 latency", cbBlock); \
+        RTTestIValueF((uint64_t)iIteration * cbBlock / ((double)ns / RT_NS_1SEC), \
+                      RTTESTUNIT_BYTES_PER_SEC,     a_szOperation "/seq/%RU32 throughput", cbBlock); \
+        RTTestIValueF(iIteration, \
+                      RTTESTUNIT_CALLS,             a_szOperation "/seq/%RU32 calls", cbBlock); \
+        RTTestIValueF((uint64_t)iIteration * cbBlock, \
+                      RTTESTUNIT_BYTES,             a_szOperation "/seq/%RU32 bytes", cbBlock); \
+        RTTestIValueF(cSeeks, \
+                      RTTESTUNIT_OCCURRENCES,       a_szOperation "/seq/%RU32 seeks", cbBlock); \
+        if (g_fShowDuration) \
+            RTTestIValueF(ns, RTTESTUNIT_NS,        a_szOperation "/seq/%RU32 duration", cbBlock); \
+    } while (0)
+
+
+/**
+ * One RTFileRead profiling iteration.
+ */
+DECL_FORCE_INLINE(int) fsPerfIoReadWorker(RTFILE hFile1, uint64_t cbFile, uint32_t cbBlock, uint8_t *pbBlock,
+                                          uint64_t *poffActual, uint32_t *pcSeeks)
+{
+    /* Do we need to seek back to the start? */
+    if (*poffActual + cbBlock <= cbFile)
+    { /* likely */ }
+    else
+    {
+        RTTESTI_CHECK_RC_RET(RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS, rcCheck);
+        *pcSeeks += 1;
+        *poffActual = 0;
+    }
+
+    size_t cbActuallyRead = 0;
+    RTTESTI_CHECK_RC_RET(RTFileRead(hFile1, pbBlock, cbBlock, &cbActuallyRead), VINF_SUCCESS, rcCheck);
+    if (cbActuallyRead == cbBlock)
+    {
+        *poffActual += cbActuallyRead;
+        return VINF_SUCCESS;
+    }
+    RTTestIFailed("RTFileRead at %#RX64 returned just %#x bytes, expected %#x", *poffActual, cbActuallyRead, cbBlock);
+    *poffActual += cbActuallyRead;
+    return VERR_READ_ERROR;
+}
+
+
+void fsPerfIoReadBlockSize(RTFILE hFile1, uint64_t cbFile, uint32_t cbBlock)
+{
+    RTTestISubF("IO - Sequential read %RU32", cbBlock);
+
+    uint8_t *pbBuf = (uint8_t *)RTMemPageAlloc(cbBlock);
+    if (pbBuf)
+    {
+        memset(pbBuf, 0xf7, cbBlock);
+        PROFILE_IO_FN("RTFileRead", fsPerfIoReadWorker(hFile1, cbFile, cbBlock, pbBuf, &offActual, &cSeeks));
+        RTMemPageFree(pbBuf, cbBlock);
+    }
+    else
+        RTTestSkipped(g_hTest, "insufficient (virtual) memory available");
+}
+
+
+void fsPerfRead(RTFILE hFile1, RTFILE hFileNoCache, uint64_t cbFile)
+{
+    RTTestISubF("IO - RTFileRead");
+
+    /*
+     * Allocate a big buffer we can play around with.  Min size is 1MB.
+     */
+    size_t   cbBuf = cbFile < _64M ? (size_t)cbFile : _64M;
+    uint8_t *pbBuf = (uint8_t *)RTMemPageAlloc(cbBuf);
+    while (!pbBuf)
+    {
+        cbBuf /= 2;
+        RTTESTI_CHECK_RETV(cbBuf >= _1M);
+        pbBuf = (uint8_t *)RTMemPageAlloc(_32M);
+    }
+
+#if 1
+    /*
+     * Start at the beginning and read the full buffer in random small chunks, thereby
+     * checking that unaligned buffer addresses, size and file offsets work fine.
+     */
+    struct
+    {
+        uint64_t offFile;
+        uint32_t cbMax;
+    } aRuns[] = { { 0, 127 }, { cbFile - cbBuf, UINT32_MAX }, { 0, UINT32_MAX -1 }};
+    for (uint32_t i = 0; i < RT_ELEMENTS(aRuns); i++)
+    {
+        memset(pbBuf, 0x55, cbBuf);
+        RTTESTI_CHECK_RC(RTFileSeek(hFile1, aRuns[i].offFile, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+        for (size_t offBuf = 0; offBuf < cbBuf; )
+        {
+            uint32_t const cbLeft   = (uint32_t)(cbBuf - offBuf);
+            uint32_t const cbToRead = aRuns[i].cbMax < UINT32_MAX / 2 ? RTRandU32Ex(1, RT_MIN(aRuns[i].cbMax, cbLeft))
+                                    : aRuns[i].cbMax == UINT32_MAX    ? RTRandU32Ex(RT_MAX(cbLeft / 4, 1), cbLeft)
+                                    :                                   RTRandU32Ex(cbLeft >= _8K ? _8K : 1, RT_MIN(_1M, cbLeft));
+            size_t cbActual = 0;
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, &pbBuf[offBuf], cbToRead, &cbActual), VINF_SUCCESS);
+            if (cbActual == cbToRead)
+                offBuf += cbActual;
+            else
+            {
+                RTTestIFailed("Attempting to read %#x bytes at %#zx, only got %#x bytes back! (cbLeft=%#x cbBuf=%#zx)\n",
+                              cbToRead, offBuf, cbActual, cbLeft, cbBuf);
+                if (cbActual)
+                    offBuf += cbActual;
+                else
+                    pbBuf[offBuf++] = 0x11;
+            }
+        }
+        fsPerfCheckReadBuf(__LINE__, aRuns[i].offFile, pbBuf, cbBuf);
+    }
+#endif
+
+    /*
+     * Test reading beyond the end of the file.
+     */
+    size_t   const acbMax[] = { cbBuf, _64K, _16K, _4K, 256 };
+    uint32_t const aoffFromEos[] =
+    {   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 32, 63, 64, 127, 128, 255, 254, 256, 1023, 1024, 2048,
+        4092, 4093, 4094, 4095, 4096, 4097, 4098, 4099, 4100, 8192, 16384, 32767, 32768, 32769, 65535, 65536, _1M - 1
+    };
+    for (unsigned iMax = 0; iMax < RT_ELEMENTS(acbMax); iMax++)
+    {
+        size_t const cbMaxRead = acbMax[iMax];
+        for (uint32_t iOffFromEos = 0; iOffFromEos < RT_ELEMENTS(aoffFromEos); iOffFromEos++)
+        {
+            uint32_t off = aoffFromEos[iOffFromEos];
+            if (off >= cbMaxRead)
+                continue;
+            RTTESTI_CHECK_RC(RTFileSeek(hFile1, cbFile - off, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+            size_t cbActual = ~(size_t)0;
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, pbBuf, cbMaxRead, &cbActual), VINF_SUCCESS);
+            RTTESTI_CHECK(cbActual == off);
+
+            RTTESTI_CHECK_RC(RTFileSeek(hFile1, cbFile - off, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+            cbActual = ~(size_t)0;
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, pbBuf, off, &cbActual), VINF_SUCCESS);
+            RTTESTI_CHECK_MSG(cbActual == off, ("%#zx vs %#zx", cbActual, off));
+
+            cbActual = ~(size_t)0;
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, pbBuf, 1, &cbActual), VINF_SUCCESS);
+            RTTESTI_CHECK(cbActual == 0);
+
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, pbBuf, cbMaxRead, NULL), VERR_EOF);
+        }
+    }
+
+    /*
+     * Test reading beyond end of the file.
+     */
+    for (unsigned iMax = 0; iMax < RT_ELEMENTS(acbMax); iMax++)
+    {
+        size_t const cbMaxRead = acbMax[iMax];
+        for (uint32_t off = 0; off < 256; off++)
+        {
+            RTTESTI_CHECK_RC(RTFileSeek(hFile1, cbFile + off, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+            size_t cbActual = ~(size_t)0;
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, pbBuf, cbMaxRead, &cbActual), VINF_SUCCESS);
+            RTTESTI_CHECK(cbActual == 0);
+
+            RTTESTI_CHECK_RC(RTFileRead(hFile1, pbBuf, cbMaxRead, NULL), VERR_EOF);
+        }
+    }
+
+    /*
+     * Do uncached access, must be page aligned.
+     */
+    uint32_t cbPage = PAGE_SIZE;
+    memset(pbBuf, 0x66, cbBuf);
+    RTTESTI_CHECK_RC(RTFileSeek(hFileNoCache, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+    for (size_t offBuf = 0; offBuf < cbBuf; )
+    {
+        uint32_t const cPagesLeft   = (uint32_t)((cbBuf - offBuf) / cbPage);
+        uint32_t const cPagesToRead = RTRandU32Ex(1, cPagesLeft);
+        size_t const   cbToRead     = cPagesToRead * (size_t)cbPage;
+        size_t cbActual = 0;
+        RTTESTI_CHECK_RC(RTFileRead(hFileNoCache, &pbBuf[offBuf], cbToRead, &cbActual), VINF_SUCCESS);
+        if (cbActual == cbToRead)
+            offBuf += cbActual;
+        else
+        {
+            RTTestIFailed("Attempting to read %#zx bytes at %#zx, only got %#x bytes back!\n", cbToRead, offBuf, cbActual);
+            if (cbActual)
+                offBuf += cbActual;
+            else
+            {
+                memset(&pbBuf[offBuf], 0x11, cbPage);
+                offBuf += cbPage;
+            }
+        }
+    }
+    fsPerfCheckReadBuf(__LINE__, 0, pbBuf, cbBuf);
+
+    /*
+     * Check reading zero bytes at the end of the file.
+     * Requires native call because RTFileWrite doesn't call kernel on zero byte reads.
+     */
+    RTTESTI_CHECK_RC(RTFileSeek(hFile1, 0, RTFILE_SEEK_END, NULL), VINF_SUCCESS);
+#ifdef RT_OS_WINDOWS
+    IO_STATUS_BLOCK Ios       = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    NTSTATUS rcNt = NtReadFile((HANDLE)RTFileToNative(hFile1), NULL, NULL, NULL, &Ios, pbBuf, 0, NULL, NULL);
+    RTTESTI_CHECK_MSG(rcNt == STATUS_SUCCESS, ("rcNt=%#x", rcNt));
+    RTTESTI_CHECK(Ios.Status == STATUS_SUCCESS);
+    RTTESTI_CHECK(Ios.Information == 0);
+
+    RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+    rcNt = NtReadFile((HANDLE)RTFileToNative(hFile1), NULL, NULL, NULL, &Ios, pbBuf, 1, NULL, NULL);
+    RTTESTI_CHECK_MSG(rcNt == STATUS_END_OF_FILE, ("rcNt=%#x", rcNt));
+    RTTESTI_CHECK(Ios.Status == STATUS_END_OF_FILE);
+    RTTESTI_CHECK(Ios.Information == 0);
+#else
+    ssize_t cbRead = read((int)RTFileToNative(hFile1), pbBuf, 0);
+    RTTESTI_CHECK(cbRead == 0);
+#endif
+
+    /*
+     * Other OS specific stuff.
+     */
+#ifdef RT_OS_WINDOWS
+    /* Check that reading at an offset modifies the position: */
+    RTTESTI_CHECK_RC(RTFileSeek(hFile1, 0, RTFILE_SEEK_END, NULL), VINF_SUCCESS);
+    RTTESTI_CHECK(RTFileTell(hFile1) == cbFile);
+
+    RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+    LARGE_INTEGER offNt;
+    offNt.QuadPart = cbFile / 2;
+    rcNt = NtReadFile((HANDLE)RTFileToNative(hFile1), NULL, NULL, NULL, &Ios, pbBuf, _4K, &offNt, NULL);
+    RTTESTI_CHECK_MSG(rcNt == STATUS_SUCCESS, ("rcNt=%#x", rcNt));
+    RTTESTI_CHECK(Ios.Status == STATUS_SUCCESS);
+    RTTESTI_CHECK(Ios.Information == _4K);
+    RTTESTI_CHECK(RTFileTell(hFile1) == cbFile / 2 + _4K);
+    fsPerfCheckReadBuf(__LINE__, cbFile / 2, pbBuf, _4K);
+#endif
+
+    RTMemPageFree(pbBuf, cbBuf);
+}
+
+
+/**
+ * One RTFileWrite profiling iteration.
+ */
+DECL_FORCE_INLINE(int) fsPerfIoWriteWorker(RTFILE hFile1, uint64_t cbFile, uint32_t cbBlock, uint8_t *pbBlock,
+                                           uint64_t *poffActual, uint32_t *pcSeeks)
+{
+    /* Do we need to seek back to the start? */
+    if (*poffActual + cbBlock <= cbFile)
+    { /* likely */ }
+    else
+    {
+        RTTESTI_CHECK_RC_RET(RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS, rcCheck);
+        *pcSeeks += 1;
+        *poffActual = 0;
+    }
+
+    size_t cbActuallyWritten = 0;
+    RTTESTI_CHECK_RC_RET(RTFileWrite(hFile1, pbBlock, cbBlock, &cbActuallyWritten), VINF_SUCCESS, rcCheck);
+    if (cbActuallyWritten == cbBlock)
+    {
+        *poffActual += cbActuallyWritten;
+        return VINF_SUCCESS;
+    }
+    RTTestIFailed("RTFileWrite at %#RX64 returned just %#x bytes, expected %#x", *poffActual, cbActuallyWritten, cbBlock);
+    *poffActual += cbActuallyWritten;
+    return VERR_WRITE_ERROR;
+}
+
+
+void fsPerfIoWriteBlockSize(RTFILE hFile1, uint64_t cbFile, uint32_t cbBlock)
+{
+    RTTestISubF("IO - Sequential write %RU32", cbBlock);
+
+    uint8_t *pbBuf = (uint8_t *)RTMemPageAlloc(cbBlock);
+    if (pbBuf)
+    {
+        memset(pbBuf, 0xf7, cbBlock);
+        PROFILE_IO_FN("RTFileWrite", fsPerfIoWriteWorker(hFile1, cbFile, cbBlock, pbBuf, &offActual, &cSeeks));
+        RTMemPageFree(pbBuf, cbBlock);
+    }
+    else
+        RTTestSkipped(g_hTest, "insufficient (virtual) memory available");
+}
+
+
+void fsPerfWrite(RTFILE hFile1, RTFILE hFileNoCache, RTFILE hFileWriteThru, uint64_t cbFile)
+{
+    RTTestISubF("IO - RTFileWrite");
+
+    /*
+     * Allocate a big buffer we can play around with.  Min size is 1MB.
+     */
+    size_t   cbBuf = cbFile < _64M ? (size_t)cbFile : _64M;
+    uint8_t *pbBuf = (uint8_t *)RTMemPageAlloc(cbBuf);
+    while (!pbBuf)
+    {
+        cbBuf /= 2;
+        RTTESTI_CHECK_RETV(cbBuf >= _1M);
+        pbBuf = (uint8_t *)RTMemPageAlloc(_32M);
+    }
+
+    /*
+     * Start at the beginning and write out the full buffer in random small chunks, thereby
+     * checking that unaligned buffer addresses, size and file offsets work fine.
+     */
+    struct
+    {
+        uint64_t offFile;
+        uint32_t cbMax;
+    } aRuns[] = { { 0, 127 }, { cbFile - cbBuf, UINT32_MAX }, { 0, UINT32_MAX -1 }};
+    uint8_t bFiller = 0x88;
+    for (uint32_t i = 0; i < RT_ELEMENTS(aRuns); i++, bFiller)
+    {
+        fsPerfFillWriteBuf(aRuns[i].offFile, pbBuf, cbBuf, bFiller);
+        fsPerfCheckReadBuf(__LINE__, aRuns[i].offFile, pbBuf, cbBuf, bFiller);
+
+        RTTESTI_CHECK_RC(RTFileSeek(hFile1, aRuns[i].offFile, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+        for (size_t offBuf = 0; offBuf < cbBuf; )
+        {
+            uint32_t const cbLeft    = (uint32_t)(cbBuf - offBuf);
+            uint32_t const cbToWrite = aRuns[i].cbMax < UINT32_MAX / 2 ? RTRandU32Ex(1, aRuns[i].cbMax)
+                                     : aRuns[i].cbMax == UINT32_MAX    ? RTRandU32Ex(RT_MAX(cbLeft / 4, 1), cbLeft)
+                                     : RTRandU32Ex(cbLeft >= _8K ? _8K : 1, RT_MIN(_1M, cbLeft));
+            size_t cbActual = 0;
+            RTTESTI_CHECK_RC(RTFileWrite(hFile1, &pbBuf[offBuf], cbToWrite, &cbActual), VINF_SUCCESS);
+            if (cbActual == cbToWrite)
+                offBuf += cbActual;
+            else
+            {
+                RTTestIFailed("Attempting to write %#x bytes at %#zx, only got %#x written!\n", cbToWrite, offBuf, cbActual);
+                if (cbActual)
+                    offBuf += cbActual;
+                else
+                    pbBuf[offBuf++] = 0x11;
+            }
+        }
+
+        RTTESTI_CHECK_RC(RTFileReadAt(hFile1, aRuns[i].offFile, pbBuf, cbBuf, NULL), VINF_SUCCESS);
+        fsPerfCheckReadBuf(__LINE__, aRuns[i].offFile, pbBuf, cbBuf, bFiller);
+    }
+
+
+    /*
+     * Do uncached and write-thru accesses, must be page aligned.
+     */
+    RTFILE ahFiles[2] = { hFileWriteThru, hFileNoCache };
+    for (unsigned iFile = 0; iFile < RT_ELEMENTS(ahFiles); iFile++, bFiller++)
+    {
+        fsPerfFillWriteBuf(0, pbBuf, cbBuf, bFiller);
+        fsPerfCheckReadBuf(__LINE__, 0, pbBuf, cbBuf, bFiller);
+        RTTESTI_CHECK_RC(RTFileSeek(ahFiles[iFile], 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+
+        uint32_t cbPage = PAGE_SIZE;
+        for (size_t offBuf = 0; offBuf < cbBuf; )
+        {
+            uint32_t const cPagesLeft    = (uint32_t)((cbBuf - offBuf) / cbPage);
+            uint32_t const cPagesToWrite = RTRandU32Ex(1, cPagesLeft);
+            size_t const   cbToWrite     = cPagesToWrite * (size_t)cbPage;
+            size_t cbActual = 0;
+            RTTESTI_CHECK_RC(RTFileWrite(ahFiles[iFile], &pbBuf[offBuf], cbToWrite, &cbActual), VINF_SUCCESS);
+            if (cbActual == cbToWrite)
+            {
+                RTTESTI_CHECK_RC(RTFileReadAt(hFile1, offBuf, pbBuf, cbToWrite, NULL), VINF_SUCCESS);
+                fsPerfCheckReadBuf(__LINE__, offBuf, pbBuf, cbToWrite, bFiller);
+                offBuf += cbActual;
+            }
+            else
+            {
+                RTTestIFailed("Attempting to read %#zx bytes at %#zx, only got %#x written!\n", cbToWrite, offBuf, cbActual);
+                if (cbActual)
+                    offBuf += cbActual;
+                else
+                {
+                    memset(&pbBuf[offBuf], 0x11, cbPage);
+                    offBuf += cbPage;
+                }
+            }
+        }
+
+        RTTESTI_CHECK_RC(RTFileReadAt(ahFiles[iFile], 0, pbBuf, cbBuf, NULL), VINF_SUCCESS);
+        fsPerfCheckReadBuf(__LINE__, 0, pbBuf, cbBuf, bFiller);
+    }
+
+    /*
+     * Check the behavior of writing zero bytes to the file _4K from the end
+     * using native API.  In the olden days zero sized write have been known
+     * to be used to truncate a file.
+     */
+    RTTESTI_CHECK_RC(RTFileSeek(hFile1, -_4K, RTFILE_SEEK_END, NULL), VINF_SUCCESS);
+#ifdef RT_OS_WINDOWS
+    IO_STATUS_BLOCK Ios        = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    NTSTATUS rcNt = NtWriteFile((HANDLE)RTFileToNative(hFile1), NULL, NULL, NULL, &Ios, pbBuf, 0, NULL, NULL);
+    RTTESTI_CHECK_MSG(rcNt == STATUS_SUCCESS, ("rcNt=%#x", rcNt));
+    RTTESTI_CHECK(Ios.Status == STATUS_SUCCESS);
+    RTTESTI_CHECK(Ios.Information == 0);
+#else
+    ssize_t cbWritten = write((int)RTFileToNative(hFile1), pbBuf, 0);
+    RTTESTI_CHECK(cbWritten == 0);
+#endif
+    RTTESTI_CHECK_RC(RTFileRead(hFile1, pbBuf, _4K, NULL), VINF_SUCCESS);
+    fsPerfCheckReadBuf(__LINE__, cbFile - _4K, pbBuf, _4K, pbBuf[0x8]);
+
+    /*
+     * Other OS specific stuff.
+     */
+#ifdef RT_OS_WINDOWS
+    /* Check that reading at an offset modifies the position: */
+    RTTESTI_CHECK_RC(RTFileReadAt(hFile1, cbFile / 2, pbBuf, _4K, NULL), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileSeek(hFile1, 0, RTFILE_SEEK_END, NULL), VINF_SUCCESS);
+    RTTESTI_CHECK(RTFileTell(hFile1) == cbFile);
+
+    RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+    LARGE_INTEGER offNt;
+    offNt.QuadPart = cbFile / 2;
+    rcNt = NtWriteFile((HANDLE)RTFileToNative(hFile1), NULL, NULL, NULL, &Ios, pbBuf, _4K, &offNt, NULL);
+    RTTESTI_CHECK_MSG(rcNt == STATUS_SUCCESS, ("rcNt=%#x", rcNt));
+    RTTESTI_CHECK(Ios.Status == STATUS_SUCCESS);
+    RTTESTI_CHECK(Ios.Information == _4K);
+    RTTESTI_CHECK(RTFileTell(hFile1) == cbFile / 2 + _4K);
+#endif
+
+    RT_NOREF(hFileNoCache, hFileWriteThru);
+    RTMemPageFree(pbBuf, cbBuf);
+}
+
+
+/**
+ * Worker for testing RTFileFlush.
+ */
+DECL_FORCE_INLINE(int) fsPerfFSyncWorker(RTFILE hFile1, uint64_t cbFile, uint8_t *pbBuf, size_t cbBuf, uint64_t *poffFile)
+{
+    if (*poffFile + cbBuf <= cbFile)
+    { /* likely */ }
+    else
+    {
+        RTTESTI_CHECK_RC(RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+        *poffFile = 0;
+    }
+
+    RTTESTI_CHECK_RC_RET(RTFileWrite(hFile1, pbBuf, cbBuf, NULL), VINF_SUCCESS, rcCheck);
+    RTTESTI_CHECK_RC_RET(RTFileFlush(hFile1), VINF_SUCCESS, rcCheck);
+
+    *poffFile += cbBuf;
+    return VINF_SUCCESS;
+}
+
+
+void fsPerfFSync(RTFILE hFile1, uint64_t cbFile)
+{
+    RTTestISub("fsync");
+
+    RTTESTI_CHECK_RC(RTFileFlush(hFile1), VINF_SUCCESS);
+
+    PROFILE_FN(RTFileFlush(hFile1), g_nsTestRun, "RTFileFlush");
+
+    size_t   cbBuf = PAGE_SIZE;
+    uint8_t *pbBuf = (uint8_t *)RTMemPageAlloc(cbBuf);
+    RTTESTI_CHECK_RETV(pbBuf != NULL);
+    memset(pbBuf, 0xf4, cbBuf);
+
+    RTTESTI_CHECK_RC(RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+    uint64_t offFile = 0;
+    PROFILE_FN(fsPerfFSyncWorker(hFile1, cbFile, pbBuf, cbBuf, &offFile), g_nsTestRun, "RTFileWrite[Page]/RTFileFlush");
+
+    RTMemPageFree(pbBuf, cbBuf);
+}
+
+
+void fsPerfMMap(RTFILE hFile1, RTFILE hFileNoCache, uint64_t cbFile)
+{
+    RTTestISub("mmap");
+#if defined(RT_OS_WINDOWS) || defined(RT_OS_LINUX)
+    static const char * const s_apszStates[] = { "readonly", "writecopy", "readwrite" };
+    enum { kMMap_ReadOnly = 0, kMMap_WriteCopy, kMMap_ReadWrite, kMMap_End };
+    for (int enmState = kMMap_ReadOnly; enmState < kMMap_End; enmState++)
+    {
+        /*
+         * Do the mapping.
+         */
+        size_t cbMapping = (size_t)cbFile;
+        if (cbMapping != cbFile)
+            cbMapping = _256M;
+        uint8_t *pbMapping;
+
+# ifdef RT_OS_WINDOWS
+        HANDLE hSection;
+        for (;; cbMapping /= 2)
+        {
+            hSection = CreateFileMapping((HANDLE)RTFileToNative(hFile1), NULL,
+                                         enmState == kMMap_ReadOnly    ? PAGE_READONLY
+                                         : enmState == kMMap_WriteCopy ? PAGE_WRITECOPY : PAGE_READWRITE,
+                                         (uint32_t)((uint64_t)cbMapping >> 32), (uint32_t)cbMapping, NULL);
+            DWORD dwErr1 = GetLastError();
+            DWORD dwErr2 = 0;
+            if (hSection != NULL)
+            {
+                pbMapping = (uint8_t *)MapViewOfFile(hSection,
+                                                     enmState == kMMap_ReadOnly    ? FILE_MAP_READ
+                                                     : enmState == kMMap_WriteCopy ? FILE_MAP_COPY
+                                                     :                               FILE_MAP_WRITE,
+                                                     0, 0, cbMapping);
+                if (pbMapping)
+                    break;
+                dwErr2 = GetLastError();
+                CloseHandle(hSection);
+            }
+            if (cbMapping <= _2M)
+            {
+                RTTestIFailed("%u: CreateFileMapping or MapViewOfFile failed: %u, %u", enmState, dwErr1, dwErr2);
+                return;
+            }
+        }
+# else
+        for (;; cbMapping /= 2)
+        {
+            pbMapping = (uint8_t *)mmap(NULL, cbMapping,
+                                        enmState == kMMap_ReadOnly  ? PROT_READ   : PROT_READ | PROT_WRITE,
+                                        enmState == kMMap_WriteCopy ? MAP_PRIVATE : MAP_SHARED,
+                                        (int)RTFileToNative(hFile1), 0);
+            if ((void *)pbMapping != MAP_FAILED)
+                break;
+            RTTESTI_CHECK_MSG_RETV(cbMapping > _2M, ("errno=%d", errno));
+        }
+# endif
+
+        /*
+         * Time page-ins just for fun.
+         */
+        size_t const cPages = cbMapping >> PAGE_SHIFT;
+        size_t uDummy = 0;
+        uint64_t ns = RTTimeNanoTS();
+        for (size_t iPage = 0; iPage < cPages; iPage++)
+            uDummy += ASMAtomicReadU8(&pbMapping[iPage << PAGE_SHIFT]);
+        ns = RTTimeNanoTS() - ns;
+        RTTestIValueF(ns / cPages, RTTESTUNIT_NS_PER_OCCURRENCE,  "page-in %s", s_apszStates[enmState]);
+
+        /* Check the content. */
+        fsPerfCheckReadBuf(__LINE__, 0, pbMapping, cbMapping);
+
+        if (enmState != kMMap_ReadOnly)
+        {
+            /* Write stuff to the first two megabytes.  In the COW case, we'll detect
+               corruption of shared data during content checking of the RW iterations. */
+            fsPerfFillWriteBuf(0, pbMapping, _2M, 0xf7);
+            if (enmState == kMMap_ReadWrite)
+            {
+                /* For RW we can try read back from the file handle and check if we get
+                   a match there first.  */
+                uint8_t abBuf[_4K];
+                for (uint32_t off = 0; off < _2M; off += sizeof(abBuf))
+                {
+                    RTTESTI_CHECK_RC(RTFileReadAt(hFile1, off, abBuf, sizeof(abBuf), NULL), VINF_SUCCESS);
+                    fsPerfCheckReadBuf(__LINE__, off, abBuf, sizeof(abBuf), 0xf7);
+                }
+# ifdef RT_OS_WINDOWS
+                RTTESTI_CHECK(FlushViewOfFile(pbMapping, _2M));
+# else
+                RTTESTI_CHECK(msync(pbMapping, _2M, MS_SYNC) == 0);
+# endif
+
+                /*
+                 * Time modifying and flushing a few different number of pages.
+                 */
+                static size_t const s_acbFlush[] = { PAGE_SIZE, PAGE_SIZE * 2, PAGE_SIZE * 3, PAGE_SIZE * 8, PAGE_SIZE * 16, _2M };
+                for (unsigned iFlushSize = 0 ; iFlushSize < RT_ELEMENTS(s_acbFlush); iFlushSize++)
+                {
+                    size_t const cbFlush = s_acbFlush[iFlushSize];
+                    if (cbFlush > cbMapping)
+                        continue;
+
+# if defined(RT_OS_LINUX)
+                    size_t const cFlushes = RT_MIN(cbMapping / cbFlush, 2048);
+# else
+                    size_t const cFlushes = cbMapping / cbFlush;
+# endif
+                    uint8_t     *pbCur    = pbMapping;
+                    ns = RTTimeNanoTS();
+                    for (size_t iFlush = 0; iFlush < cFlushes; iFlush++, pbCur += cbFlush)
+                    {
+                        for (size_t offFlush = 0; offFlush < cbFlush; offFlush += PAGE_SIZE)
+                            *(size_t volatile *)&pbCur[offFlush + 8] = cbFlush;
+# ifdef RT_OS_WINDOWS
+                        RTTESTI_CHECK(FlushViewOfFile(pbCur, cbFlush));
+# else
+                        RTTESTI_CHECK(msync(pbCur, cbFlush, MS_SYNC) == 0);
+# endif
+                    }
+                    ns = RTTimeNanoTS() - ns;
+                    RTTestIValueF(ns / cFlushes, RTTESTUNIT_NS_PER_OCCURRENCE,  "touch/flush/%zu", cbFlush);
+
+                    /*
+                     * Check that all the changes made it thru to the file:
+                     */
+                    size_t   cbBuf = _2M;
+                    uint8_t *pbBuf = (uint8_t *)RTMemPageAlloc(_2M);
+                    if (!pbBuf)
+                    {
+                        cbBuf = _4K;
+                        pbBuf = (uint8_t *)RTMemPageAlloc(_2M);
+                    }
+                    if (pbBuf)
+                    {
+                        RTTESTI_CHECK_RC(RTFileSeek(hFileNoCache, 0, RTFILE_SEEK_BEGIN, NULL), VINF_SUCCESS);
+                        size_t const cbToCheck = cFlushes * cbFlush;
+                        unsigned     cErrors   = 0;
+                        for (size_t offBuf = 0; cErrors < 32 && offBuf < cbToCheck; offBuf += cbBuf)
+                        {
+                            size_t cbToRead = RT_MIN(cbBuf, cbToCheck - offBuf);
+                            RTTESTI_CHECK_RC(RTFileRead(hFileNoCache, pbBuf, cbToRead, NULL), VINF_SUCCESS);
+
+                            for (size_t offFlush = 0; offFlush < cbToRead; offFlush += PAGE_SIZE)
+                                if (*(size_t volatile *)&pbBuf[offFlush + 8] != cbFlush)
+                                {
+                                    RTTestIFailed("Flush issue at offset #%zx: %#zx, expected %#zx (cbFlush=%#zx)",
+                                                  offBuf, *(size_t volatile *)&pbBuf[offFlush + 8], cbFlush, cbFlush);
+                                    if (++cErrors > 32)
+                                        break;
+                                }
+                        }
+                        RTMemPageFree(pbBuf, cbBuf);
+                    }
+                }
+            }
+        }
+
+        /*
+         * Unmap it.
+         */
+# ifdef RT_OS_WINDOWS
+        RTTESTI_CHECK(UnmapViewOfFile(pbMapping));
+        RTTESTI_CHECK(CloseHandle(hSection));
+# else
+        RTTESTI_CHECK(munmap(pbMapping, cbMapping) == 0);
+# endif
+    }
+
+    RT_NOREF(hFileNoCache);
+#else
+    RTTestSkipped(g_hTest,  "not supported/implemented");
+    RT_NOREF(hFile1, hFileNoCache, cbFile);
+#endif
+}
+
+
+/**
+ * This does the read, write and seek tests.
+ */
+void fsPerfIo(void)
+{
+    RTTestISub("I/O");
+
+    /*
+     * Determin the size of the test file.
+     */
+    g_szDir[g_cchDir] = '\0';
+    RTFOFF cbFree = 0;
+    RTTESTI_CHECK_RC_RETV(RTFsQuerySizes(g_szDir, NULL, &cbFree, NULL, NULL), VINF_SUCCESS);
+    uint64_t cbFile = g_cbIoFile;
+    if (cbFile + _16M < (uint64_t)cbFree)
+        cbFile = RT_ALIGN_64(cbFile, _64K);
+    else
+    {
+        if (cbFree < _32M)
+        {
+            RTTestSkipped(g_hTest, "Insufficent free space: %'RU64 bytes, requires >= 32MB", cbFree);
+            return;
+        }
+        cbFile = cbFree - (cbFree > _128M ? _64M : _16M);
+        cbFile = RT_ALIGN_64(cbFile, _64K);
+        RTTestIPrintf(RTTESTLVL_ALWAYS,  "Adjusted file size to %'RU64 bytes, due to %'RU64 bytes free.\n", cbFile, cbFree);
+    }
+    if (cbFile < _64K)
+    {
+        RTTestSkipped(g_hTest, "Specified test file size too small: %'RU64 bytes, requires >= 64KB", cbFile);
+        return;
+    }
+
+    /*
+     * Create a cbFile sized test file.
+     */
+    RTFILE hFile1;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFile1, InDir(RT_STR_TUPLE("file21")),
+                                     RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE | RTFILE_O_READWRITE), VINF_SUCCESS);
+    RTFILE hFileNoCache;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFileNoCache, g_szDir,
+                                     RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_READWRITE | RTFILE_O_NO_CACHE),
+                          VINF_SUCCESS);
+    RTFILE hFileWriteThru;
+    RTTESTI_CHECK_RC_RETV(RTFileOpen(&hFileWriteThru, g_szDir,
+                                     RTFILE_O_OPEN | RTFILE_O_DENY_NONE | RTFILE_O_READWRITE | RTFILE_O_WRITE_THROUGH),
+                          VINF_SUCCESS);
+
+    uint8_t *pbFree = NULL;
+    int rc = fsPerfIoPrepFile(hFile1, cbFile, &pbFree);
+    RTMemFree(pbFree);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Do the testing & profiling.
+         */
+        if (g_fSeek)
+            fsPerfIoSeek(hFile1, cbFile);
+        if (g_fRead)
+        {
+            fsPerfRead(hFile1, hFileNoCache, cbFile);
+            for (unsigned i = 0; i < g_cIoBlocks; i++)
+                fsPerfIoReadBlockSize(hFile1, cbFile, g_acbIoBlocks[i]);
+        }
+        if (g_fMMap)
+            fsPerfMMap(hFile1, hFileNoCache, cbFile);
+        if (g_fWrite)
+        {
+            /* This is destructive to the file content. */
+            fsPerfWrite(hFile1, hFileNoCache, hFileWriteThru, cbFile);
+            for (unsigned i = 0; i < g_cIoBlocks; i++)
+                fsPerfIoWriteBlockSize(hFile1, cbFile, g_acbIoBlocks[i]);
+        }
+        if (g_fFSync)
+            fsPerfFSync(hFile1, cbFile);
+    }
+
+    RTTESTI_CHECK_RC(RTFileSetSize(hFile1, 0), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFile1), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFileNoCache), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileClose(hFileWriteThru), VINF_SUCCESS);
+    RTTESTI_CHECK_RC(RTFileDelete(g_szDir), VINF_SUCCESS);
+}
+
+
+static void Usage(PRTSTREAM pStrm)
+{
+    char szExec[RTPATH_MAX];
+    RTStrmPrintf(pStrm, "usage: %s <-d <testdir>> [options]\n",
+                 RTPathFilename(RTProcGetExecutablePath(szExec, sizeof(szExec))));
+    RTStrmPrintf(pStrm, "\n");
+    RTStrmPrintf(pStrm, "options: \n");
+
+    for (unsigned i = 0; i < RT_ELEMENTS(g_aCmdOptions); i++)
+    {
+        char szHelp[80];
+        const char *pszHelp;
+        switch (g_aCmdOptions[i].iShort)
+        {
+            case 'd':   pszHelp = "The directory to use for testing.  Default: CWD/fstestdir"; break;
+            case 'e':   pszHelp = "Enables all tests.   Default: -e"; break;
+            case 'z':   pszHelp = "Disables all tests.  Default: -e"; break;
+            case 's':   pszHelp = "Set benchmark duration in seconds.  Default: 10 sec"; break;
+            case 'm':   pszHelp = "Set benchmark duration in milliseconds.  Default: 10000 ms"; break;
+            case 'v':   pszHelp = "More verbose execution."; break;
+            case 'q':   pszHelp = "Quiet execution."; break;
+            case 'h':   pszHelp = "Displays this help and exit"; break;
+            case 'V':   pszHelp = "Displays the program revision"; break;
+            default:
+                if (g_aCmdOptions[i].iShort >= kCmdOpt_First)
+                {
+                    if (RTStrStartsWith(g_aCmdOptions[i].pszLong, "--no-"))
+                        RTStrPrintf(szHelp, sizeof(szHelp), "Disables the '%s' test.", g_aCmdOptions[i].pszLong + 5);
+                    else
+                        RTStrPrintf(szHelp, sizeof(szHelp), "Enables  the '%s' test.", g_aCmdOptions[i].pszLong + 2);
+                    pszHelp = szHelp;
+                }
+                else
+                    pszHelp = "Option undocumented";
+                break;
+        }
+        if ((unsigned)g_aCmdOptions[i].iShort < 127U)
+        {
+            char szOpt[64];
+            RTStrPrintf(szOpt, sizeof(szOpt), "%s, -%c", g_aCmdOptions[i].pszLong, g_aCmdOptions[i].iShort);
+            RTStrmPrintf(pStrm, "  %-20s%s\n", szOpt, pszHelp);
+        }
+        else
+            RTStrmPrintf(pStrm, "  %-20s%s\n", g_aCmdOptions[i].pszLong, pszHelp);
+    }
+}
+
+
+int main(int argc, char *argv[])
+{
+    /*
+     * Init IPRT and globals.
+     */
+    int rc = RTTestInitAndCreate("FsPerf", &g_hTest);
+    if (rc)
+        return rc;
+    RTListInit(&g_ManyTreeHead);
+
+    /*
+     * Default values.
+     */
+    rc = RTPathGetCurrent(g_szDir, sizeof(g_szDir) / 2);
+    if (RT_SUCCESS(rc))
+        rc = RTPathAppend(g_szDir, sizeof(g_szDir) / 2, "fstestdir-");
+    if (RT_SUCCESS(rc))
+    {
+        g_cchDir = strlen(g_szDir);
+        g_cchDir += RTStrPrintf(&g_szDir[g_cchDir], sizeof(g_szDir) - g_cchDir, "%u" RTPATH_SLASH_STR, RTProcSelf());
+    }
+    else
+    {
+        RTTestFailed(g_hTest, "RTPathGetCurrent (or RTPathAppend) failed: %Rrc\n", rc);
+        return RTTestSummaryAndDestroy(g_hTest);
+    }
+
+    RTGETOPTUNION ValueUnion;
+    RTGETOPTSTATE GetState;
+    RTGetOptInit(&GetState, argc, argv, g_aCmdOptions, RT_ELEMENTS(g_aCmdOptions), 1, 0 /* fFlags */);
+    while ((rc = RTGetOpt(&GetState, &ValueUnion)) != 0)
+    {
+        switch (rc)
+        {
+            case 'd':
+                rc = RTPathAbs(ValueUnion.psz, g_szDir, sizeof(g_szDir) / 2);
+                if (RT_SUCCESS(rc))
+                    break;
+                RTTestFailed(g_hTest, "RTPathAbs(%s) failed: %Rrc\n", ValueUnion.psz, rc);
+                return RTTestSummaryAndDestroy(g_hTest);
+
+            case 's':
+                if (ValueUnion.u32 == 0)
+                    g_nsTestRun = RT_NS_1SEC_64 * 10;
+                else
+                    g_nsTestRun = ValueUnion.u32 * RT_NS_1SEC_64;
+                break;
+
+            case 'm':
+                if (ValueUnion.u64 == 0)
+                    g_nsTestRun = RT_NS_1SEC_64 * 10;
+                else
+                    g_nsTestRun = ValueUnion.u64 * RT_NS_1MS;
+                break;
+
+            case 'e':
+                g_fManyFiles = true;
+                g_fOpen      = true;
+                g_fFStat     = true;
+                g_fFChMod    = true;
+                g_fFUtimes   = true;
+                g_fStat      = true;
+                g_fChMod     = true;
+                g_fUtimes    = true;
+                g_fRename    = true;
+                g_fDirEnum   = true;
+                g_fMkRmDir   = true;
+                g_fStatVfs   = true;
+                g_fRm        = true;
+                g_fChSize    = true;
+                g_fRead      = true;
+                g_fWrite     = true;
+                g_fSeek      = true;
+                g_fFSync     = true;
+                g_fMMap      = true;
+                break;
+
+            case 'z':
+                g_fManyFiles = false;
+                g_fOpen      = false;
+                g_fFStat     = false;
+                g_fFChMod    = false;
+                g_fFUtimes   = false;
+                g_fStat      = false;
+                g_fChMod     = false;
+                g_fUtimes    = false;
+                g_fRename    = false;
+                g_fDirEnum   = false;
+                g_fMkRmDir   = false;
+                g_fStatVfs   = false;
+                g_fRm        = false;
+                g_fChSize    = false;
+                g_fRead      = false;
+                g_fWrite     = false;
+                g_fSeek      = false;
+                g_fFSync     = false;
+                g_fMMap      = false;
+                break;
+
+#define CASE_OPT(a_Stem) \
+            case RT_CONCAT(kCmdOpt_,a_Stem):   RT_CONCAT(g_f,a_Stem) = true; break; \
+            case RT_CONCAT(kCmdOpt_No,a_Stem): RT_CONCAT(g_f,a_Stem) = false; break
+            CASE_OPT(ManyFiles);
+            CASE_OPT(Open);
+            CASE_OPT(FStat);
+            CASE_OPT(FChMod);
+            CASE_OPT(FUtimes);
+            CASE_OPT(Stat);
+            CASE_OPT(ChMod);
+            CASE_OPT(Utimes);
+            CASE_OPT(Rename);
+            CASE_OPT(DirEnum);
+            CASE_OPT(MkRmDir);
+            CASE_OPT(StatVfs);
+            CASE_OPT(Rm);
+            CASE_OPT(ChSize);
+            CASE_OPT(Read);
+            CASE_OPT(Write);
+            CASE_OPT(Seek);
+            CASE_OPT(FSync);
+            CASE_OPT(MMap);
+#undef CASE_OPT
+
+            case 'q':
+                g_uVerbosity = 0;
+                break;
+
+            case 'v':
+                g_uVerbosity++;
+                break;
+
+            case 'h':
+                Usage(g_pStdOut);
+                return RTEXITCODE_SUCCESS;
+
+            case 'V':
+            {
+                char szRev[] = "$Revision: 128290 $";
+                szRev[RT_ELEMENTS(szRev) - 2] = '\0';
+                RTPrintf(RTStrStrip(strchr(szRev, ':') + 1));
+                return RTEXITCODE_SUCCESS;
+            }
+
+            default:
+                return RTGetOptPrintError(rc, &ValueUnion);
+        }
+    }
+
+    /*
+     * Create the test directory with an 'empty' subdirectory under it,
+     * execute the tests, and remove directory when done.
+     */
+    RTTestBanner(g_hTest);
+    if (!RTPathExists(g_szDir))
+    {
+        /* The base dir: */
+        rc = RTDirCreate(g_szDir, 0755,
+                         RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_DONT_SET | RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_NOT_CRITICAL);
+        if (RT_SUCCESS(rc))
+        {
+            RTTestIPrintf(RTTESTLVL_ALWAYS, "Test  dir: %s\n", g_szDir);
+            rc = fsPrepTestArea();
+            if (RT_SUCCESS(rc))
+            {
+                /* Profile RTTimeNanoTS(). */
+                fsPerfNanoTS();
+
+                /* Do tests: */
+                if (g_fManyFiles)
+                    fsPerfManyFiles();
+                if (g_fOpen)
+                    fsPerfOpen();
+                if (g_fFStat)
+                    fsPerfFStat();
+                if (g_fFChMod)
+                    fsPerfFChMod();
+                if (g_fFUtimes)
+                    fsPerfFUtimes();
+                if (g_fStat)
+                    fsPerfStat();
+                if (g_fChMod)
+                    fsPerfChmod();
+                if (g_fUtimes)
+                    fsPerfUtimes();
+                if (g_fRename)
+                    fsPerfRename();
+                if (g_fDirEnum)
+                    vsPerfDirEnum();
+                if (g_fMkRmDir)
+                    fsPerfMkRmDir();
+                if (g_fStatVfs)
+                    fsPerfStatVfs();
+                if (g_fRm || g_fManyFiles)
+                    fsPerfRm(); /* deletes manyfiles and manytree */
+                if (g_fChSize)
+                    fsPerfChSize();
+                if (g_fRead || g_fWrite || g_fSeek || g_fFSync || g_fMMap)
+                    fsPerfIo();
+            }
+
+            /* Cleanup: */
+            g_szDir[g_cchDir] = '\0';
+            rc = RTDirRemoveRecursive(g_szDir, RTDIRRMREC_F_CONTENT_AND_DIR);
+            if (RT_FAILURE(rc))
+                RTTestFailed(g_hTest, "RTDirRemoveRecursive(%s,) -> %Rrc\n", g_szDir, rc);
+        }
+        else
+            RTTestFailed(g_hTest, "RTDirCreate(%s) -> %Rrc\n", g_szDir, rc);
+    }
+    else
+        RTTestFailed(g_hTest, "Test directory already exists: %s\n", g_szDir);
+
+    return RTTestSummaryAndDestroy(g_hTest);
+}
diff --git a/src/VBox/ValidationKit/utils/fs/Makefile.kmk b/src/VBox/ValidationKit/utils/fs/Makefile.kmk
new file mode 100644
index 00000000..a51e8c54
--- /dev/null
+++ b/src/VBox/ValidationKit/utils/fs/Makefile.kmk
@@ -0,0 +1,39 @@
+# $Id: Makefile.kmk $
+## @file
+# VirtualBox Validation Kit - File system tests.
+#
+
+#
+# Copyright (C) 2010-2019 Oracle Corporation
+#
+# This file is part of VirtualBox Open Source Edition (OSE), as
+# available from http://www.virtualbox.org. This file is free software;
+# you can redistribute it and/or modify it under the terms of the GNU
+# General Public License (GPL) as published by the Free Software
+# Foundation, in version 2 as it comes in the "COPYING" file of the
+# VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+# hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+#
+# The contents of this file may alternatively be used under the terms
+# of the Common Development and Distribution License Version 1.0
+# (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+# VirtualBox OSE distribution, in which case the provisions of the
+# CDDL are applicable instead of those of the GPL.
+#
+# You may elect to license modified versions of this file under the
+# terms and conditions of either the GPL or the CDDL or both.
+#
+
+SUB_DEPTH = ../../../../..
+include $(KBUILD_PATH)/subheader.kmk
+
+#
+# File System Performance (think shared folders).
+#
+PROGRAMS += FsPerf
+FsPerf_TEMPLATE = VBoxValidationKitR3
+FsPerf_SOURCES  = FsPerf.cpp
+
+$(evalcall def_vbox_validationkit_process_python_sources)
+include $(FILE_KBUILD_SUB_FOOTER)
+