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/* $Id: nttimesources.cpp $ */
/** @file
* Check the various time sources on Windows NT.
*/
/*
* Copyright (C) 2009-2023 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 *
*********************************************************************************************************************************/
#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 / (long double)u64TscHz * 1000000 : u64MicroSecMs;
uint64_t u64MicroSecPrf = (long double)cPrfTicks.QuadPart / (long double)PrfHz.QuadPart * 1000000;
uint64_t u64MicroSecInt = cIntTicks.QuadPart / 10; /* 100ns units*/
/* 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);
}
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