Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: [PATCH 1/4 v2] sched/fair: relax constraint on task's load during load balance | Date | Wed, 23 Sep 2020 15:43:19 +0100 |
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On 21/09/20 08:24, Vincent Guittot wrote: > Some UCs like 9 always running tasks on 8 CPUs can't be balanced and the > load balancer currently migrates the waiting task between the CPUs in an > almost random manner. The success of a rq pulling a task depends of the > value of nr_balance_failed of its domains and its ability to be faster > than others to detach it. This behavior results in an unfair distribution > of the running time between tasks because some CPUs will run most of the > time, if not always, the same task whereas others will share their time > between several tasks. > > Instead of using nr_balance_failed as a boolean to relax the condition > for detaching task, the LB will use nr_balanced_failed to relax the > threshold between the tasks'load and the imbalance. This mecanism > prevents the same rq or domain to always win the load balance fight. > > Reviewed-by: Phil Auld <pauld@redhat.com> > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
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