| From | "Rafael J. Wysocki" <> | Date | Tue, 19 Apr 2022 17:34:56 +0200 | Subject | Re: [patch 01/10] x86/aperfmperf: Dont wake idle CPUs in arch_freq_get_on_cpu() |
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On Fri, Apr 15, 2022 at 9:19 PM Thomas Gleixner <tglx@linutronix.de> wrote: > > aperfmperf_get_khz() already excludes idle CPUs from APERF/MPERF sampling > and that's a reasonable decision. There is no point in sending up to two > IPIs to an idle CPU just because someone reads a sysfs file. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> --- > arch/x86/kernel/cpu/aperfmperf.c | 3 +++ > 1 file changed, 3 insertions(+) > > --- a/arch/x86/kernel/cpu/aperfmperf.c > +++ b/arch/x86/kernel/cpu/aperfmperf.c > @@ -139,6 +139,9 @@ unsigned int arch_freq_get_on_cpu(int cp > if (!housekeeping_cpu(cpu, HK_TYPE_MISC)) > return 0; > > + if (rcu_is_idle_cpu(cpu)) > + return 0; > + > if (aperfmperf_snapshot_cpu(cpu, ktime_get(), true)) > return per_cpu(samples.khz, cpu); > >
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