Messages in this thread | | | Date | Fri, 12 Nov 2021 17:25:01 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 03/13] perf/x86/amd: add AMD Fam19h Branch Sampling support |
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On Thu, Nov 11, 2021 at 12:44:05AM -0800, Stephane Eranian wrote: > @@ -989,6 +1165,23 @@ static int __init amd_core_pmu_init(void) > x86_pmu.flags |= PMU_FL_PAIR; > } > > + if (boot_cpu_data.x86 >= 0x19) { > + /* > + * On AMD, invoking pmu_disable_all() is very expensive and the function is > + * invoked on context-switch in via sched_task_in(), so enable only when necessary > + */
Well, it only gets called when brs is in use, so afaict the above comment is a bit misleading. Still no point in installing that function when there it no point for it.
> + if (!amd_brs_init()) { > + x86_pmu.get_event_constraints = amd_get_event_constraints_f19h; > + x86_pmu.sched_task = amd_pmu_sched_task; > + /* > + * The put_event_constraints callback is shared with > + * Fam17h, set above > + */ > + } > + } > + > + x86_pmu.attr_update = amd_attr_update; > + > pr_cont("core perfctr, "); > return 0; > }
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