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pcm: allow core 0 to be offlined #957

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Merged
rdementi merged 1 commit into from
Jun 16, 2025
Merged

pcm: allow core 0 to be offlined #957

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28 changes: 22 additions & 6 deletions src/cpucounters.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -359,7 +359,7 @@ bool PCM::isHWTMAL1Supported() const
void PCM::readCPUMicrocodeLevel()
{
if (MSR.empty()) return;
const int ref_core = 0;
const int32 ref_core = socketRefCore[0];
TemporalThreadAffinity affinity(ref_core);
if (affinity.supported() && isCoreOnline(ref_core))
{ // see "Update Signature and Verification" and "Determining the Signature"
Expand Down Expand Up @@ -1110,7 +1110,22 @@ bool PCM::discoverSystemTopology()
};
std::unordered_map<int, domain> topologyDomainMap;
{
TemporalThreadAffinity aff0(0);
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const int32 maxTopoDomainAff = 1<<16;
int32 topoDomainAff = -1;

for (int32 core = 0; core < maxTopoDomainAff; ++core)
{
try {
TemporalThreadAffinity _(core);
topoDomainAff = core;
}
catch (...)
{
}
if (topoDomainAff != -1) break;
}

TemporalThreadAffinity _(topoDomainAff);

if (initCoreMasks(smtMaskWidth, coreMaskWidth, l2CacheMaskShift, l3CacheMaskShift) == false)
{
Expand Down Expand Up @@ -4637,7 +4652,7 @@ uint64 RDTSC();

void PCM::computeNominalFrequency()
{
const int ref_core = 0;
const int32 ref_core = socketRefCore[0];
const uint64 before = getInvariantTSC_Fast(ref_core);
MySleepMs(100);
const uint64 after = getInvariantTSC_Fast(ref_core);
Expand Down Expand Up @@ -4809,11 +4824,11 @@ void PCM::computeQPISpeedBeckton(int core_nr)
MSR[core_nr]->read(R_MSR_PMON_CTR0, &startFlits);

const uint64 timerGranularity = 1000000ULL; // mks
uint64 startTSC = getTickCount(timerGranularity, (uint32) core_nr);
uint64 startTSC = getTickCount(timerGranularity, core_nr);
uint64 endTSC;
do
{
endTSC = getTickCount(timerGranularity, (uint32) core_nr);
endTSC = getTickCount(timerGranularity, core_nr);
} while (endTSC - startTSC < 200000ULL); // spin for 200 ms

uint64 endFlits = 0;
Expand Down Expand Up @@ -5401,8 +5416,9 @@ int convertUnknownToInt(size_t size, char* value)
#endif


uint64 PCM::getTickCount(uint64 multiplier, uint32 core)
uint64 PCM::getTickCount(uint64 multiplier, int32 core)
{
if (core == -1) core = socketRefCore[0];
return (multiplier * getInvariantTSC_Fast(core)) / getNominalFrequency();
}

Expand Down
4 changes: 2 additions & 2 deletions src/cpucounters.h
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Expand Up @@ -2304,9 +2304,9 @@ class PCM_API PCM
}
//! \brief Return TSC timer value in time units
//! \param multiplier use 1 for seconds, 1000 for ms, 1000000 for mks, etc (default is 1000: ms)
//! \param core core to read on-chip TSC value (default is 0)
//! \param core core to read on-chip TSC value (default is -1: socketRefCore[0])
//! \return time counter value
uint64 getTickCount(uint64 multiplier = 1000 /* ms */, uint32 core = 0);
uint64 getTickCount(uint64 multiplier = 1000 /* ms */, int32 core = -1);

uint64 getInvariantTSC_Fast(uint32 core = 0);

Expand Down
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