TMAllCpu.cpp revision 4aa3f5e786c3a76fe766552d62fd4de49b73cdac
/* $Id$ */
/** @file
* TM - Timeout Manager, CPU Time, All Contexts.
*/
/*
* Copyright (C) 2006-2007 Sun Microsystems, Inc.
*
* 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.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#define LOG_GROUP LOG_GROUP_TM
#include <VBox/tm.h>
#include "../TMInternal.h"
#include <VBox/vm.h>
#include <VBox/sup.h>
#include <VBox/param.h>
#include <VBox/err.h>
#include <iprt/assert.h>
#include <iprt/asm.h>
#include <VBox/log.h>
/**
* Gets the raw cpu tick from current virtual time.
*/
DECLINLINE(uint64_t) tmCpuTickGetRawVirtual(PVM pVM, bool fCheckTimers)
{
uint64_t u64 = TMVirtualSyncGetEx(pVM, fCheckTimers);
if (u64 != TMCLOCK_FREQ_VIRTUAL)
u64 = ASMMultU64ByU32DivByU32(u64, pVM->tm.s.cTSCTicksPerSecond, TMCLOCK_FREQ_VIRTUAL);
return u64;
}
/**
* Resumes the CPU timestamp counter ticking.
*
* @returns VBox status code.
* @param pVM The VM to operate on.
* @param pVCpu The VMCPU to operate on.
* @internal
*/
int tmCpuTickResume(PVM pVM, PVMCPU pVCpu)
{
if (!pVCpu->tm.s.fTSCTicking)
{
pVCpu->tm.s.fTSCTicking = true;
if (pVM->tm.s.fTSCVirtualized)
{
/** @todo Test that pausing and resuming doesn't cause lag! (I.e. that we're
* unpaused before the virtual time and stopped after it. */
if (pVM->tm.s.fTSCUseRealTSC)
pVCpu->tm.s.u64TSCOffset = ASMReadTSC() - pVCpu->tm.s.u64TSC;
else
pVCpu->tm.s.u64TSCOffset = tmCpuTickGetRawVirtual(pVM, false /* don't check for pending timers */)
- pVCpu->tm.s.u64TSC;
}
return VINF_SUCCESS;
}
AssertFailed();
return VERR_INTERNAL_ERROR;
}
/**
* Pauses the CPU timestamp counter ticking.
*
* @returns VBox status code.
* @param pVM The VM to operate on.
* @param pVCpu The VMCPU to operate on.
* @internal
*/
int tmCpuTickPause(PVM pVM, PVMCPU pVCpu)
{
if (pVCpu->tm.s.fTSCTicking)
{
pVCpu->tm.s.u64TSC = TMCpuTickGetNoCheck(pVCpu);
pVCpu->tm.s.fTSCTicking = false;
return VINF_SUCCESS;
}
AssertFailed();
return VERR_INTERNAL_ERROR;
}
/**
* Checks if AMD-V / VT-x can use an offsetted hardware TSC or not.
*
* @returns true/false accordingly.
* @param pVCpu The VMCPU to operate on.
* @param poffRealTSC The offset against the TSC of the current CPU.
* Can be NULL.
* @thread EMT.
*/
VMMDECL(bool) TMCpuTickCanUseRealTSC(PVMCPU pVCpu, uint64_t *poffRealTSC)
{
PVM pVM = pVCpu->CTX_SUFF(pVM);
/*
* We require:
* 1. A fixed TSC, this is checked at init time.
* 2. That the TSC is ticking (we shouldn't be here if it isn't)
* 3. Either that we're using the real TSC as time source or
* a) we don't have any lag to catch up, and
* b) the virtual sync clock hasn't been halted by an expired timer, and
* c) we're not using warp drive (accelerated virtual guest time).
*/
if ( pVM->tm.s.fMaybeUseOffsettedHostTSC
&& RT_LIKELY(pVCpu->tm.s.fTSCTicking)
&& ( pVM->tm.s.fTSCUseRealTSC
|| ( !pVM->tm.s.fVirtualSyncCatchUp
&& RT_LIKELY(pVM->tm.s.fVirtualSyncTicking)
&& !pVM->tm.s.fVirtualWarpDrive))
)
{
if (!pVM->tm.s.fTSCUseRealTSC)
{
/* The source is the timer synchronous virtual clock. */
Assert(pVM->tm.s.fTSCVirtualized);
if (poffRealTSC)
{
uint64_t u64Now = tmCpuTickGetRawVirtual(pVM, false /* don't check for pending timers */)
- pVCpu->tm.s.u64TSCOffset;
/** @todo When we start collecting statistics on how much time we spend executing
* guest code before exiting, we should check this against the next virtual sync
* timer timeout. If it's lower than the avg. length, we should trap rdtsc to increase
* the chance that we'll get interrupted right after the timer expired. */
*poffRealTSC = u64Now - ASMReadTSC();
}
}
else if (poffRealTSC)
{
/* The source is the real TSC. */
if (pVM->tm.s.fTSCVirtualized)
*poffRealTSC = pVCpu->tm.s.u64TSCOffset;
else
*poffRealTSC = 0;
}
/** @todo count this? */
return true;
}
#ifdef VBOX_WITH_STATISTICS
/* Sample the reason for refusing. */
if (!pVM->tm.s.fMaybeUseOffsettedHostTSC)
STAM_COUNTER_INC(&pVM->tm.s.StatTSCNotFixed);
else if (!pVCpu->tm.s.fTSCTicking)
STAM_COUNTER_INC(&pVM->tm.s.StatTSCNotTicking);
else if (!pVM->tm.s.fTSCUseRealTSC)
{
if (pVM->tm.s.fVirtualSyncCatchUp)
{
if (pVM->tm.s.u32VirtualSyncCatchUpPercentage <= 10)
STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupLE010);
else if (pVM->tm.s.u32VirtualSyncCatchUpPercentage <= 25)
STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupLE025);
else if (pVM->tm.s.u32VirtualSyncCatchUpPercentage <= 100)
STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupLE100);
else
STAM_COUNTER_INC(&pVM->tm.s.StatTSCCatchupOther);
}
else if (!pVM->tm.s.fVirtualSyncTicking)
STAM_COUNTER_INC(&pVM->tm.s.StatTSCSyncNotTicking);
else if (pVM->tm.s.fVirtualWarpDrive)
STAM_COUNTER_INC(&pVM->tm.s.StatTSCWarp);
}
#endif
return false;
}
/**
* Read the current CPU timstamp counter.
*
* @returns Gets the CPU tsc.
* @param pVCpu The VMCPU to operate on.
*/
DECLINLINE(uint64_t) tmCpuTickGetInternal(PVMCPU pVCpu, bool fCheckTimers)
{
uint64_t u64;
if (RT_LIKELY(pVCpu->tm.s.fTSCTicking))
{
PVM pVM = pVCpu->CTX_SUFF(pVM);
if (pVM->tm.s.fTSCVirtualized)
{
if (pVM->tm.s.fTSCUseRealTSC)
u64 = ASMReadTSC();
else
u64 = tmCpuTickGetRawVirtual(pVM, fCheckTimers);
u64 -= pVCpu->tm.s.u64TSCOffset;
}
else
u64 = ASMReadTSC();
}
else
u64 = pVCpu->tm.s.u64TSC;
return u64;
}
/**
* Read the current CPU timstamp counter.
*
* @returns Gets the CPU tsc.
* @param pVCpu The VMCPU to operate on.
*/
VMMDECL(uint64_t) TMCpuTickGet(PVMCPU pVCpu)
{
return tmCpuTickGetInternal(pVCpu, true /* fCheckTimers */);
}
/**
* Read the current CPU timstamp counter, don't check for expired timers.
*
* @returns Gets the CPU tsc.
* @param pVCpu The VMCPU to operate on.
*/
VMMDECL(uint64_t) TMCpuTickGetNoCheck(PVMCPU pVCpu)
{
return tmCpuTickGetInternal(pVCpu, false /* fCheckTimers */);
}
/**
* Sets the current CPU timestamp counter.
*
* @returns VBox status code.
* @param pVM The VM handle.
* @param pVCpu The virtual CPU to operate on.
* @param u64Tick The new timestamp value.
*
* @thread EMT which TSC is to be set.
*/
VMMDECL(int) TMCpuTickSet(PVM pVM, PVMCPU pVCpu, uint64_t u64Tick)
{
VMCPU_ASSERT_EMT(pVCpu);
STAM_COUNTER_INC(&pVM->tm.s.StatTSCSet);
/*
* This is easier to do when the TSC is paused since resume will
* do all the calcuations for us. Actually, we don't need to
* call tmCpuTickPause here since we overwrite u64TSC anyway.
*/
bool fTSCTicking = pVCpu->tm.s.fTSCTicking;
pVCpu->tm.s.fTSCTicking = false;
pVCpu->tm.s.u64TSC = u64Tick;
if (fTSCTicking)
tmCpuTickResume(pVM, pVCpu);
/** @todo Try help synchronizing it better among the virtual CPUs? */
return VINF_SUCCESS;
}
/**
* Get the timestamp frequency.
*
* @returns Number of ticks per second.
* @param pVM The VM.
*/
VMMDECL(uint64_t) TMCpuTicksPerSecond(PVM pVM)
{
if (pVM->tm.s.fTSCUseRealTSC)
{
uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGIP(g_pSUPGlobalInfoPage);
if (RT_LIKELY(cTSCTicksPerSecond != ~(uint64_t)0))
return cTSCTicksPerSecond;
}
return pVM->tm.s.cTSCTicksPerSecond;
}