On Wed, Jan 22, 2014 at 9:53 AM, <bseg...@google.com> wrote:
> Vincent Guittot <vincent.guit...@linaro.org> writes:
>
>> This reverts commit 282cf499f03ec1754b6c8c945c9674b02631fb0f.
>>
>> With the current implementation, the load average statistics of a sched
>> entity
>> change according to other activity on the CPU even if this activity is done
>> between the running window of the sched entity and have no influence on the
>> running duration of the task.
>>
>> When a task wakes up on the same CPU, we currently update
>> last_runnable_update
>> with the return of __synchronize_entity_decay without updating the
>> runnable_avg_sum and runnable_avg_period accordingly. In fact, we have to
>> sync
>> the load_contrib of the se with the rq's blocked_load_contrib before removing
>> it from the latter (with __synchronize_entity_decay) but we must keep
>> last_runnable_update unchanged for updating runnable_avg_sum/period during
>> the
>> next update_entity_load_avg.
>>
>> Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org>
> Unless paul wants to squash this into a possible change to the if
> (wakeup) stuff:
> Reviewed-by: Ben Segall <bseg...@google.com>
>
I can send that separately as Vincent suggests. This is good to go.
>>
>> ---
>> kernel/sched/fair.c | 8 +-------
>> 1 file changed, 1 insertion(+), 7 deletions(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index e64b079..6d61f20 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -2365,13 +2365,7 @@ static inline void enqueue_entity_load_avg(struct
>> cfs_rq *cfs_rq,
>> }
>> wakeup = 0;
>> } else {
>> - /*
>> - * Task re-woke on same cpu (or else migrate_task_rq_fair()
>> - * would have made count negative); we must be careful to avoid
>> - * double-accounting blocked time after synchronizing decays.
>> - */
>> - se->avg.last_runnable_update += __synchronize_entity_decay(se)
>> - << 20;
>> + __synchronize_entity_decay(se);
>> }
>>
>> /* migrated tasks did not contribute to our blocked load */
--
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