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| author | Vincent Guittot <vincent.guittot@linaro.org> | 2020-06-24 17:44:22 +0200 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2020-06-30 15:36:13 -0400 |
| commit | f3f0e114c088da075998e9dcf1d5ce6ee6a754ee (patch) | |
| tree | d37c5bb71f0e0a971a688c826301d185e63477ff /kernel | |
| parent | 3fa41459aa64de784d68cb87ea6a6d3a3e38e5e3 (diff) | |
sched/cfs: change initial value of runnable_avg
[ Upstream commit e21cf43406a190adfcc4bfe592768066fb3aaa9b ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2ae7e30ccb33..5725199b32dc 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -807,7 +807,7 @@ 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) { /* |