From e0f5f3afd2cffa96291cd852056d83ff4e2e99c7 Mon Sep 17 00:00:00 2001 From: Dietmar Eggemann Date: Fri, 14 Aug 2015 17:23:09 +0100 Subject: sched/fair: Make load tracking frequency scale-invariant Apply frequency scaling correction factor to per-entity load tracking to make it frequency invariant. Currently, load appears bigger when the CPU is running slower which affects load-balancing decisions. Each segment of the sched_avg.load_sum geometric series is now scaled by the current frequency so that the sched_avg.load_avg of each sched entity will be invariant from frequency scaling. Moreover, cfs_rq.runnable_load_sum is scaled by the current frequency as well. Signed-off-by: Dietmar Eggemann Signed-off-by: Morten Rasmussen Signed-off-by: Peter Zijlstra (Intel) Acked-by: Vincent Guittot Cc: Dietmar Eggemann 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: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1439569394-11974-2-git-send-email-morten.rasmussen@arm.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index a4ab9daa387c..c8d923ba429d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1177,9 +1177,9 @@ struct load_weight { /* * The load_avg/util_avg accumulates an infinite geometric series. - * 1) load_avg factors the amount of time that a sched_entity is - * runnable on a rq into its weight. For cfs_rq, it is the aggregated - * such weights of all runnable and blocked sched_entities. + * 1) load_avg factors frequency scaling into the amount of time that a + * sched_entity is runnable on a rq into its weight. For cfs_rq, it is the + * aggregated such weights of all runnable and blocked sched_entities. * 2) util_avg factors frequency scaling into the amount of time * that a sched_entity is running on a CPU, in the range [0..SCHED_LOAD_SCALE]. * For cfs_rq, it is the aggregated such times of all runnable and -- cgit v1.2.3