pcm: allow core 0 to be offlined#957
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rdementi merged 1 commit intointel:masterfrom Jun 16, 2025
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opcm
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thanks. Please address the remaining issue
src/cpucounters.cpp
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| std::unordered_map<int, domain> topologyDomainMap; | ||
| { | ||
| TemporalThreadAffinity aff0(0); | ||
| const int32 maxTopoDomainAff = 8; |
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this will fail if the first 8 cores are offlined which is a realistic scenario. Please increase the max to 1<<16
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On servers with Intel SST-PP enabled, it seems core 0 can be put offline, and pcm will fail to start. I corrected
ref_corefrom hardcoded0to usesocketRefCore, and relaxed thread affinityaff0requirement during system topology discovery, now it works on my test environment.Before:
$sudo ./pcm ===== Processor information ===== Linux arch_perfmon flag : yes Hybrid processor : no IBRS and IBPB supported : yes STIBP supported : yes Spec arch caps supported : yes Max CPUID level : 36 CPU family : 6 CPU model number : 173 ERROR: pthread_setaffinity_np for core 0 failed with code 22 PCM ERROR. Exception pthread_setaffinity_np failedAfter:
$sudo ./pcm ===== Processor information ===== Linux arch_perfmon flag : yes Hybrid processor : no IBRS and IBPB supported : yes STIBP supported : yes Spec arch caps supported : yes Max CPUID level : 36 CPU family : 6 CPU model number : 173 Number of logical cores: 240 .... Core (SKT) | UTIL | IPC | CFREQ | L3MISS | L2MISS | L3HIT | L2HIT | L3MPI | L2MPI | L3OCC | LMB | RMB | TEMP 2 0 0.14 0.17 ... 3 0 0.01 0.29 ... 5 0 0.00 0.18 ... 6 0 0.00 0.17 ... 8 0 0.00 0.22 ... 9 0 0.00 0.29 ...