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authorVincent Guittot <vincent.guittot@linaro.org>2020-06-24 17:44:22 +0200
committerBorislav Petkov <bp@suse.de>2020-06-28 17:01:20 +0200
commite21cf43406a190adfcc4bfe592768066fb3aaa9b (patch)
treee5f7d137033c19c399fc285d5931a737f7be4f2f /kernel/sched/fair.c
parent8c4890d1c3358fb8023d46e1e554c41d54f02878 (diff)
downloadlinux-e21cf43406a190adfcc4bfe592768066fb3aaa9b.tar.gz
sched/cfs: change initial value of runnable_avg
Some performance regression on reaim benchmark have been raised with commit 070f5e860ee2 ("sched/fair: Take into account runnable_avg to classify group") The problem comes from the init value of runnable_avg which is initialized with max value. This can be a problem if the newly forked task is finally a short task because the group of CPUs is wrongly set to overloaded and tasks are pulled less agressively. Set initial value of runnable_avg equals to util_avg to reflect that there is no waiting time so far. Fixes: 070f5e860ee2 ("sched/fair: Take into account runnable_avg to classify group") Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200624154422.29166-1-vincent.guittot@linaro.org
Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index cbcb2f71599b..658aa7a2ae6f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -806,7 +806,7 @@ void post_init_entity_util_avg(struct task_struct *p)
}
}
- sa->runnable_avg = cpu_scale;
+ sa->runnable_avg = sa->util_avg;
if (p->sched_class != &fair_sched_class) {
/*