The following commit has been merged into the x86/cleanups branch of tip: Commit-ID: 6d108c96bf23598cc3b4f91d60e9b7694abcd2a7 Gitweb: https://git.kernel.org/tip/6d108c96bf23598cc3b4f91d60e9b7694abcd2a7 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Fri, 15 Apr 2022 21:19:50 +02:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Wed, 27 Apr 2022 15:51:08 +02:00 x86/aperfmperf: Dont wake idle CPUs in arch_freq_get_on_cpu() 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@xxxxxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220415161206.419880163@xxxxxxxxxxxxx --- arch/x86/kernel/cpu/aperfmperf.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c index 9ca008f..ea9160f 100644 --- 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 cpu) 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);
|