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Groups > linux.kernel > #1425114
| From | Vincent Guittot <vincent.guittot@linaro.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 2/4] sched/fair: Fix PELT integrity for new groups |
| Date | 2016-06-17 16:00 +0200 |
| Message-ID | <rL2tr-7fP-15@gated-at.bofh.it> (permalink) |
| References | <rL0KZ-6mx-9@gated-at.bofh.it> <rL0L0-6mx-31@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 17 June 2016 at 14:01, Peter Zijlstra <peterz@infradead.org> wrote:
> Vincent reported that when a new task is moved into a new cgroup it
task doesn't have to be new only the cgroup
> gets attached twice to the load tracking.
>
> sched_move_task()
> task_move_group_fair()
> detach_task_cfs_rq()
> set_task_rq()
> attach_task_cfs_rq()
> attach_entity_load_avg()
> se->avg.last_load_update = cfs_rq->avg.last_load_update // == 0
>
> enqueue_entity()
> enqueue_entity_load_avg()
> update_cfs_rq_load_avg()
> now = clock()
> __update_load_avg(&cfs_rq->avg)
> cfs_rq->avg.last_load_update = now
> // ages load/util for: now - 0, load/util -> 0
> if (migrated)
> attach_entity_load_avg()
> se->avg.last_load_update = cfs_rq->avg.last_load_update; // now != 0
>
> The problem is that we don't update cfs_rq load_avg before all
> entity attach/detach operations. Only enqueue and migrate_task do
> this.
>
> By fixing this, the above will not happen, because the
> sched_move_task() attach will have updated cfs_rq's last_load_update
> time before attach, and in turn the attach will have set the entity's
> last_load_update stamp.
>
> Note that there is a further problem with sched_move_task() calling
> detach on a task that hasn't yet been attached; this will be taken
> care of in a subsequent patch.
This patch fixes the double attach
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
>
> Cc: Yuyang Du <yuyang.du@intel.com>
> Reported-by: Vincent Guittot <vincent.guittot@linaro.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> kernel/sched/fair.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -8366,6 +8366,7 @@ static void detach_task_cfs_rq(struct ta
> {
> struct sched_entity *se = &p->se;
> struct cfs_rq *cfs_rq = cfs_rq_of(se);
> + u64 now = cfs_rq_clock_task(cfs_rq);
>
> if (!vruntime_normalized(p)) {
> /*
> @@ -8377,6 +8378,7 @@ static void detach_task_cfs_rq(struct ta
> }
>
> /* Catch up with the cfs_rq and remove our load when we leave */
> + update_cfs_rq_load_avg(now, cfs_rq, false);
> detach_entity_load_avg(cfs_rq, se);
> }
>
> @@ -8384,6 +8386,7 @@ static void attach_task_cfs_rq(struct ta
> {
> struct sched_entity *se = &p->se;
> struct cfs_rq *cfs_rq = cfs_rq_of(se);
> + u64 now = cfs_rq_clock_task(cfs_rq);
>
> #ifdef CONFIG_FAIR_GROUP_SCHED
> /*
> @@ -8394,6 +8397,7 @@ static void attach_task_cfs_rq(struct ta
> #endif
>
> /* Synchronize task with its cfs_rq */
> + update_cfs_rq_load_avg(now, cfs_rq, false);
> attach_entity_load_avg(cfs_rq, se);
>
> if (!vruntime_normalized(p))
>
>
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[PATCH 0/4] sched/fair: Fix PELT wobblies Peter Zijlstra <peterz@infradead.org> - 2016-06-17 14:10 +0200
[PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-17 14:10 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-17 16:10 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-17 16:30 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-17 18:10 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-17 18:20 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-17 18:20 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Yuyang Du <yuyang.du@intel.com> - 2016-06-20 09:00 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-20 11:30 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-20 12:00 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-20 12:10 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-21 13:50 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-21 14:40 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-21 14:50 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-21 15:10 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Dietmar Eggemann <dietmar.eggemann@arm.com> - 2016-06-20 14:00 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-20 14:40 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Dietmar Eggemann <dietmar.eggemann@arm.com> - 2016-06-20 17:00 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-21 10:50 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Yuyang Du <yuyang.du@intel.com> - 2016-06-21 14:50 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-21 15:40 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-22 13:50 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-21 16:20 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Dietmar Eggemann <dietmar.eggemann@arm.com> - 2016-06-23 17:40 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-20 16:50 +0200
Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks Peter Zijlstra <peterz@infradead.org> - 2016-06-23 13:20 +0200
[PATCH 2/4] sched/fair: Fix PELT integrity for new groups Peter Zijlstra <peterz@infradead.org> - 2016-06-17 14:10 +0200
Re: [PATCH 2/4] sched/fair: Fix PELT integrity for new groups Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-17 16:00 +0200
[PATCH 3/4] sched,cgroup: Fix cpu_cgroup_fork() Peter Zijlstra <peterz@infradead.org> - 2016-06-17 14:10 +0200
Re: [PATCH 3/4] sched,cgroup: Fix cpu_cgroup_fork() Vincent Guittot <vincent.guittot@linaro.org> - 2016-06-17 16:00 +0200
Re: [PATCH 3/4] sched,cgroup: Fix cpu_cgroup_fork() Peter Zijlstra <peterz@infradead.org> - 2016-06-17 16:10 +0200
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