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| author | Thomas Gleixner <tglx@linutronix.de> | 2022-04-15 21:19:50 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2022-04-27 15:51:08 +0200 |
| commit | 6d108c96bf23598cc3b4f91d60e9b7694abcd2a7 (patch) | |
| tree | 540dfbe0ed9a54028ec0aadae727686775b1f35d /arch/x86/kernel/cpu/aperfmperf.c | |
| parent | dbb5ab6d2c0a7397d77c9f60fe23844d4fe4e634 (diff) | |
| download | linux-6d108c96bf23598cc3b4f91d60e9b7694abcd2a7.tar.gz | |
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@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20220415161206.419880163@linutronix.de
Diffstat (limited to 'arch/x86/kernel/cpu/aperfmperf.c')
| -rw-r--r-- | arch/x86/kernel/cpu/aperfmperf.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c index 9ca008f9e9b1..ea9160f7aaad 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); |