From: Dietmar Eggemann Date: Mon, 7 Sep 2015 13:57:22 +0000 (+0100) Subject: sched/fair: Defer calling scaling functions X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6f2b04524f0b38bfbb8413f98d2d6af234508309;p=linux-beck.git sched/fair: Defer calling scaling functions Do not call the scaling functions in case time goes backwards or the last update of the sched_avg structure has happened less than 1024ns ago. Signed-off-by: Dietmar Eggemann Signed-off-by: Peter Zijlstra (Intel) Cc: Juri Lelli Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: daniel.lezcano@linaro.org Cc: mturquette@baylibre.com Cc: pang.xunlei@zte.com.cn Cc: rjw@rjwysocki.net Cc: sgurrappadi@nvidia.com Cc: vincent.guittot@linaro.org Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/55EDA2E9.8040900@arm.com Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c3c5585292a6..fc835fa23308 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2552,8 +2552,7 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa, u64 delta, scaled_delta, periods; u32 contrib; unsigned int delta_w, scaled_delta_w, decayed = 0; - unsigned long scale_freq = arch_scale_freq_capacity(NULL, cpu); - unsigned long scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + unsigned long scale_freq, scale_cpu; delta = now - sa->last_update_time; /* @@ -2574,6 +2573,9 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa, return 0; sa->last_update_time = now; + scale_freq = arch_scale_freq_capacity(NULL, cpu); + scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + /* delta_w is the amount already accumulated against our next period */ delta_w = sa->period_contrib; if (delta + delta_w >= 1024) {