VirtualBox

source: vbox/trunk/src/VBox/Runtime/nt/RTSemEventMultiGetResolution-nt.cpp@ 100594

Last change on this file since 100594 was 98103, checked in by vboxsync, 23 months ago

Copyright year updates by scm.

  • Property svn:eol-style set to native
  • Property svn:keywords set to Id Revision
File size: 3.7 KB
Line 
1/* $Id: RTSemEventMultiGetResolution-nt.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
2/** @file
3 * IPRT - Single Release Event Semaphores, RTSemEventMultiGetResolution.
4 */
5
6/*
7 * Copyright (C) 2006-2023 Oracle and/or its affiliates.
8 *
9 * This file is part of VirtualBox base platform packages, as
10 * available from https://www.virtualbox.org.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation, in version 3 of the
15 * License.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, see <https://www.gnu.org/licenses>.
24 *
25 * The contents of this file may alternatively be used under the terms
26 * of the Common Development and Distribution License Version 1.0
27 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
28 * in the VirtualBox distribution, in which case the provisions of the
29 * CDDL are applicable instead of those of the GPL.
30 *
31 * You may elect to license modified versions of this file under the
32 * terms and conditions of either the GPL or the CDDL or both.
33 *
34 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
35 */
36
37
38/*********************************************************************************************************************************
39* Header Files *
40*********************************************************************************************************************************/
41#define RTSEMEVENT_WITHOUT_REMAPPING
42#ifdef IN_RING0
43# include "../r0drv/nt/the-nt-kernel.h"
44#else
45# include <iprt/nt/nt.h>
46#endif
47#include <iprt/semaphore.h>
48
49#include <iprt/assert.h>
50#include <iprt/timer.h>
51#ifdef IN_RING3
52# include <iprt/system.h>
53#endif
54
55
56RTDECL(uint32_t) RTSemEventMultiGetResolution(void)
57{
58 /*
59 * We need to figure the KeWaitForSingleObject / NtWaitForSingleObject timeout
60 * resolution, i.e. if we wish to wait for 1000ns how long are we likely to
61 * actually wait before woken up.
62 *
63 * In older versions of NT, these timeout were implemented using KTIMERs and
64 * have the same resolution as what them. This should be found using
65 * ExSetTimerResolution or NtQueryTimerResolution.
66 *
67 * Probably since windows 8.1 the value returned by NtQueryTimerResolution (and
68 * set NtSetTimerResolution) have been virtualized and no longer reflects the
69 * timer wheel resolution, at least from what I can tell. ExSetTimerResolution
70 * still works as before, but it accesses variable that I cannot find out how
71 * to access from user land. So, kernel will get (and be able to set) the right
72 * granularity, while in user land we'll be forced to reporting the max value.
73 *
74 * (The reason why I suspect it's since 8.1 is because the high resolution
75 * ExSetTimer APIs were introduced back then.)
76 */
77#ifdef IN_RING0
78 return RTTimerGetSystemGranularity();
79#else
80 ULONG cNtTicksMin = 0;
81 ULONG cNtTicksMax = 0;
82 ULONG cNtTicksCur = 0;
83 NTSTATUS rcNt = NtQueryTimerResolution(&cNtTicksMin, &cNtTicksMax, &cNtTicksCur);
84 if (NT_SUCCESS(rcNt))
85 {
86 Assert(cNtTicksMin >= cNtTicksMax);
87 if (RTSystemGetNtVersion() >= RTSYSTEM_MAKE_NT_VERSION(6,3,9600)) /** @todo check when the switch happened, might be much later... */
88 return cNtTicksMin * 100;
89 return cNtTicksCur * 100;
90 }
91 AssertFailed();
92 return 16 * RT_NS_1MS; /* the default on 64-bit windows 10 */
93#endif
94}
95
Note: See TracBrowser for help on using the repository browser.

© 2024 Oracle Support Privacy / Do Not Sell My Info Terms of Use Trademark Policy Automated Access Etiquette