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-rw-r--r--src/VBox/Runtime/nt/RTSemEventMultiGetResolution-nt.cpp95
1 files changed, 95 insertions, 0 deletions
diff --git a/src/VBox/Runtime/nt/RTSemEventMultiGetResolution-nt.cpp b/src/VBox/Runtime/nt/RTSemEventMultiGetResolution-nt.cpp
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+++ b/src/VBox/Runtime/nt/RTSemEventMultiGetResolution-nt.cpp
@@ -0,0 +1,95 @@
+/* $Id: RTSemEventMultiGetResolution-nt.cpp $ */
+/** @file
+ * IPRT - Single Release Event Semaphores, RTSemEventMultiGetResolution.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox 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.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+* Header Files *
+*********************************************************************************************************************************/
+#define RTSEMEVENT_WITHOUT_REMAPPING
+#ifdef IN_RING0
+# include "../r0drv/nt/the-nt-kernel.h"
+#else
+# include <iprt/nt/nt.h>
+#endif
+#include <iprt/semaphore.h>
+
+#include <iprt/assert.h>
+#include <iprt/timer.h>
+#ifdef IN_RING3
+# include <iprt/system.h>
+#endif
+
+
+RTDECL(uint32_t) RTSemEventMultiGetResolution(void)
+{
+ /*
+ * We need to figure the KeWaitForSingleObject / NtWaitForSingleObject timeout
+ * resolution, i.e. if we wish to wait for 1000ns how long are we likely to
+ * actually wait before woken up.
+ *
+ * In older versions of NT, these timeout were implemented using KTIMERs and
+ * have the same resolution as what them. This should be found using
+ * ExSetTimerResolution or NtQueryTimerResolution.
+ *
+ * Probably since windows 8.1 the value returned by NtQueryTimerResolution (and
+ * set NtSetTimerResolution) have been virtualized and no longer reflects the
+ * timer wheel resolution, at least from what I can tell. ExSetTimerResolution
+ * still works as before, but it accesses variable that I cannot find out how
+ * to access from user land. So, kernel will get (and be able to set) the right
+ * granularity, while in user land we'll be forced to reporting the max value.
+ *
+ * (The reason why I suspect it's since 8.1 is because the high resolution
+ * ExSetTimer APIs were introduced back then.)
+ */
+#ifdef IN_RING0
+ return RTTimerGetSystemGranularity();
+#else
+ ULONG cNtTicksMin = 0;
+ ULONG cNtTicksMax = 0;
+ ULONG cNtTicksCur = 0;
+ NTSTATUS rcNt = NtQueryTimerResolution(&cNtTicksMin, &cNtTicksMax, &cNtTicksCur);
+ if (NT_SUCCESS(rcNt))
+ {
+ Assert(cNtTicksMin >= cNtTicksMax);
+ if (RTSystemGetNtVersion() >= RTSYSTEM_MAKE_NT_VERSION(6,3,9600)) /** @todo check when the switch happened, might be much later... */
+ return cNtTicksMin * 100;
+ return cNtTicksCur * 100;
+ }
+ AssertFailed();
+ return 16 * RT_NS_1MS; /* the default on 64-bit windows 10 */
+#endif
+}
+