diff options
Diffstat (limited to 'src/VBox/ValidationKit/utils/nt/nttimesources.cpp')
| -rw-r--r-- | src/VBox/ValidationKit/utils/nt/nttimesources.cpp | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/utils/nt/nttimesources.cpp b/src/VBox/ValidationKit/utils/nt/nttimesources.cpp new file mode 100644 index 00000000..31e1e2b9 --- /dev/null +++ b/src/VBox/ValidationKit/utils/nt/nttimesources.cpp @@ -0,0 +1,236 @@ +/* $Id: nttimesources.cpp $ */ +/** @file + * Check the various time sources on Windows NT. + */ + +/* + * Copyright (C) 2009-2019 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/win/windows.h> + +#include <iprt/asm.h> +#include <iprt/asm-amd64-x86.h> +#include <iprt/errcore.h> +#include <iprt/string.h> +#include <iprt/test.h> + + +/********************************************************************************************************************************* +* Structures and Typedefs * +*********************************************************************************************************************************/ +typedef struct _MY_KSYSTEM_TIME +{ + ULONG LowPart; + LONG High1Time; + LONG High2Time; +} MY_KSYSTEM_TIME; + +typedef struct _MY_KUSER_SHARED_DATA +{ + ULONG TickCountLowDeprecated; + ULONG TickCountMultiplier; + volatile MY_KSYSTEM_TIME InterruptTime; + volatile MY_KSYSTEM_TIME SystemTime; + volatile MY_KSYSTEM_TIME TimeZoneBias; + /* The rest is not relevant. */ +} MY_KUSER_SHARED_DATA; + +/** The fixed pointer to the user shared data. */ +#define MY_USER_SHARED_DATA ((MY_KUSER_SHARED_DATA *)0x7ffe0000) + +/** Spins until GetTickCount() changes. */ +static void SpinUntilTick(void) +{ + /* spin till GetTickCount changes. */ + DWORD dwMsTick = GetTickCount(); + while (GetTickCount() == dwMsTick) + /* nothing */; +} + +/** Delay function that tries to return right after GetTickCount changed. */ +static void DelayMillies(DWORD dwMsStart, DWORD cMillies) +{ + /* Delay cMillies - 1. */ + Sleep(cMillies - 1); + while (GetTickCount() - dwMsStart < cMillies - 1U) + Sleep(1); + + SpinUntilTick(); +} + + +int main(int argc, char **argv) +{ + RT_NOREF1(argv); + + /* + * Init, create a test instance and "parse" arguments. + */ + RTTEST hTest; + int rc = RTTestInitAndCreate("nttimesources", &hTest); + if (rc) + return rc; + if (argc > 1) + { + RTTestFailed(hTest, "Syntax error! no arguments expected"); + return RTTestSummaryAndDestroy(hTest); + } + + /* + * Guess MHz using GetTickCount. + */ + RTTestSub(hTest, "Guess MHz"); + DWORD dwTickStart, dwTickEnd, cMsTicks; + uint64_t u64TscStart, u64TscEnd, cTscTicks; + + /* get a good start time. */ + SpinUntilTick(); + do + { + dwTickStart = GetTickCount(); + ASMCompilerBarrier(); + ASMSerializeInstruction(); + u64TscStart = ASMReadTSC(); + ASMCompilerBarrier(); + } while (GetTickCount() != dwTickStart); + + /* delay a good while. */ + DelayMillies(dwTickStart, 256); + + /* get a good end time. */ + do + { + dwTickEnd = GetTickCount(); + ASMCompilerBarrier(); + ASMSerializeInstruction(); + u64TscEnd = ASMReadTSC(); + ASMCompilerBarrier(); + } while (GetTickCount() != dwTickEnd); + cMsTicks = dwTickEnd - dwTickStart; + cTscTicks = u64TscEnd - u64TscStart; + + /* Calc an approximate TSC frequency: + cTscTicks / uTscHz = cMsTicks / 1000 + 1 / uTscHz = (cMsTicks / 1000) / cTscTicks + uTscHz = cTscTicks / (cMsTicks / 1000) */ + uint64_t u64TscHz = (long double)cTscTicks / ((long double)cMsTicks / 1000.0); + if ( u64TscHz > _1M*3 + && u64TscHz < _1T) + RTTestPrintf(hTest, RTTESTLVL_ALWAYS, "u64TscHz=%'llu", u64TscHz); + else + { + RTTestFailed(hTest, "u64TscHz=%'llu - out of range", u64TscHz); + u64TscHz = 0; + } + + + /* + * Pit GetTickCount, InterruptTime, Performance Counters and TSC against each other. + */ + LARGE_INTEGER PrfHz; + LARGE_INTEGER PrfStart, PrfEnd, cPrfTicks; + LARGE_INTEGER IntStart, IntEnd, cIntTicks; + for (uint32_t i = 0; i < 7; i++) + { + RTTestSubF(hTest, "The whole bunch - pass #%u", i + 1); + + if (!QueryPerformanceFrequency(&PrfHz)) + { + RTTestFailed(hTest, "QueryPerformanceFrequency failed (%u)", GetLastError()); + return RTTestSummaryAndDestroy(hTest); + } + + /* get a good start time. */ + SpinUntilTick(); + do + { + IntStart.HighPart = MY_USER_SHARED_DATA->InterruptTime.High1Time; + IntStart.LowPart = MY_USER_SHARED_DATA->InterruptTime.LowPart; + dwTickStart = GetTickCount(); + if (!QueryPerformanceCounter(&PrfStart)) + { + RTTestFailed(hTest, "QueryPerformanceCounter failed (%u)", GetLastError()); + return RTTestSummaryAndDestroy(hTest); + } + ASMCompilerBarrier(); + ASMSerializeInstruction(); + u64TscStart = ASMReadTSC(); + ASMCompilerBarrier(); + } while ( MY_USER_SHARED_DATA->InterruptTime.High2Time != IntStart.HighPart + || MY_USER_SHARED_DATA->InterruptTime.LowPart != IntStart.LowPart + || GetTickCount() != dwTickStart); + + /* delay a good while. */ + DelayMillies(dwTickStart, 256); + + /* get a good end time. */ + do + { + IntEnd.HighPart = MY_USER_SHARED_DATA->InterruptTime.High1Time; + IntEnd.LowPart = MY_USER_SHARED_DATA->InterruptTime.LowPart; + dwTickEnd = GetTickCount(); + if (!QueryPerformanceCounter(&PrfEnd)) + { + RTTestFailed(hTest, "QueryPerformanceCounter failed (%u)", GetLastError()); + return RTTestSummaryAndDestroy(hTest); + } + ASMCompilerBarrier(); + ASMSerializeInstruction(); + u64TscEnd = ASMReadTSC(); + ASMCompilerBarrier(); + } while ( MY_USER_SHARED_DATA->InterruptTime.High2Time != IntEnd.HighPart + || MY_USER_SHARED_DATA->InterruptTime.LowPart != IntEnd.LowPart + || GetTickCount() != dwTickEnd); + + cMsTicks = dwTickEnd - dwTickStart; + cTscTicks = u64TscEnd - u64TscStart; + cIntTicks.QuadPart = IntEnd.QuadPart - IntStart.QuadPart; + cPrfTicks.QuadPart = PrfEnd.QuadPart - PrfStart.QuadPart; + + /* Recalc to micro seconds. */ + uint64_t u64MicroSecMs = (uint64_t)cMsTicks * 1000; + uint64_t u64MicroSecTsc = u64TscHz ? (long double)cTscTicks / u64TscHz * 1000000 : u64MicroSecMs; + uint64_t u64MicroSecInt = cIntTicks.QuadPart / 10; /* 100ns units*/ + uint64_t u64MicroSecPrf = (long double)cPrfTicks.QuadPart / PrfHz.QuadPart * 1000000; + + /* check how much they differ using the millisecond tick count as the standard candle. */ + RTTestPrintf(hTest, RTTESTLVL_ALWAYS, " %9llu / %7lld us - GetTickCount\n", u64MicroSecMs, 0); + + int64_t off = u64MicroSecTsc - u64MicroSecMs; + RTTestPrintf(hTest, RTTESTLVL_ALWAYS, " %9llu / %7lld us - TSC\n", u64MicroSecTsc, off); + RTTEST_CHECK(hTest, RT_ABS(off) < 50000 /*us*/); /* some extra uncertainty with TSC. */ + + off = u64MicroSecInt - u64MicroSecMs; + RTTestPrintf(hTest, RTTESTLVL_ALWAYS, " %9llu / %7lld us - InterruptTime\n", u64MicroSecInt, off); + RTTEST_CHECK(hTest, RT_ABS(off) < 25000 /*us*/); + + off = u64MicroSecPrf - u64MicroSecMs; + RTTestPrintf(hTest, RTTESTLVL_ALWAYS, " %9llu / %7lld us - QueryPerformanceCounter\n", u64MicroSecPrf, off); + RTTEST_CHECK(hTest, RT_ABS(off) < 25000 /*us*/); + } + + return RTTestSummaryAndDestroy(hTest); +} + |