/**
* Get the timestamp frequency.
*
* @returns Number of ticks per second.
* @param pVM The cross context VM structure.
*/
VMMDECL(uint64_t) TMCpuTicksPerSecond(PVM pVM)
{
if ( pVM->tm.s.enmTSCMode == TMTSCMODE_REAL_TSC_OFFSET
&& g_pSUPGlobalInfoPage->u32Mode != SUPGIPMODE_INVARIANT_TSC)
{
#ifdef IN_RING3
uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGip(g_pSUPGlobalInfoPage);
#elif defined(IN_RING0)
uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, RTMpCpuIdToSetIndex(RTMpCpuId()));
#else
uint64_t cTSCTicksPerSecond = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, VMMGetCpu(pVM)->iHostCpuSet);
#endif
if (RT_LIKELY(cTSCTicksPerSecond != ~(uint64_t)0))
return cTSCTicksPerSecond;
}
return pVM->tm.s.cTSCTicksPerSecond;
}
/**
* Calculates the number of host CPU ticks till the next virtual sync deadline.
*
* @note To save work, this function will not bother calculating the accurate
* tick count for deadlines that are more than a second ahead.
*
* @returns The number of host cpu ticks to the next deadline. Max one second.
* @param pVCpu The cross context virtual CPU structure of the calling EMT.
* @param cNsToDeadline The number of nano seconds to the next virtual
* sync deadline.
*/
DECLINLINE(uint64_t) tmCpuCalcTicksToDeadline(PVMCPU pVCpu, uint64_t cNsToDeadline)
{
AssertCompile(TMCLOCK_FREQ_VIRTUAL <= _4G);
#ifdef IN_RING3
uint64_t uCpuHz = SUPGetCpuHzFromGip(g_pSUPGlobalInfoPage);
#else
uint64_t uCpuHz = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, pVCpu->iHostCpuSet);
#endif
if (RT_UNLIKELY(cNsToDeadline >= TMCLOCK_FREQ_VIRTUAL))
return uCpuHz;
uint64_t cTicks = ASMMultU64ByU32DivByU32(uCpuHz, cNsToDeadline, TMCLOCK_FREQ_VIRTUAL);
if (cTicks > 4000)
cTicks -= 4000; /* fudge to account for overhead */
else
cTicks >>= 1;
return cTicks;
}
