Messages in this thread | | | Date | Mon, 9 May 2022 18:38:19 +0530 | Subject | Re: [PATCH v4 3/7] perf/x86/amd/core: Detect PerfMonV2 support | From | Sandipan Das <> |
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On 5/9/2022 6:31 PM, Like Xu wrote: > On 27/4/2022 7:31 pm, Sandipan Das wrote: > >> x86_pmu.num_counters = AMD64_NUM_COUNTERS_CORE; > > Thus boot_cpu_has(X86_FEATURE_PERFCTR_CORE) is true. > >> + >> + /* Check for Performance Monitoring v2 support */ >> + if (boot_cpu_has(X86_FEATURE_PERFMON_V2)) { >> + /* Update PMU version for later usage */ >> + x86_pmu.version = 2; > > Is it safe to assume that once AMD CPU has the PERFMON_V2 (or further) bit, > > it must also have the PERFCTR_CORE bit set ? >
Yes, always. There won't be a case where PERFCTR_CORE is absent but PERFMON_V2 is present.
- Sandipan
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