Messages in this thread | | | Date | Sun, 20 Aug 2023 14:52:31 +0100 | From | Qais Yousef <> | Subject | Re: [PATCH v3 2/3] sched/uclamp: Ignore (util == 0) optimization in feec() when p_util_max = 0 |
| |
On 07/21/23 11:57, Vincent Guittot wrote: > On Mon, 17 Jul 2023 at 23:57, Qais Yousef <qyousef@layalina.io> wrote: > > > > find_energy_efficient_cpu() bails out early if effective util of the > > task is 0 as the delta at this point will be zero and there's nothing > > for EAS to do. When uclamp is being used, this could lead to wrong > > decisions when uclamp_max is set to 0. In this case the task is capped > > to performance point 0, but it is actually running and consuming energy > > and we can benefit from EAS energy calculations. > > > > Rework the condition so that it bails out for when util is actually 0 or > > uclamp_min is requesting a higher performance point. > > > > We can do that without needing to use uclamp_task_util(); remove it. > > > > Fixes: d81304bc6193 ("sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition") > > Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io> > > Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Thanks Vincent!
Ping in case this has fallen through the cracks. I hope it's good to be picked up now.
Thanks!
-- Qais Yousef
> > > --- > > kernel/sched/fair.c | 18 +----------------- > > 1 file changed, 1 insertion(+), 17 deletions(-) > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index d489eece5a0d..c701f490ca4c 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -4348,22 +4348,6 @@ static inline unsigned long task_util_est(struct task_struct *p) > > return max(task_util(p), _task_util_est(p)); > > } > > > > -#ifdef CONFIG_UCLAMP_TASK > > -static inline unsigned long uclamp_task_util(struct task_struct *p, > > - unsigned long uclamp_min, > > - unsigned long uclamp_max) > > -{ > > - return clamp(task_util_est(p), uclamp_min, uclamp_max); > > -} > > -#else > > -static inline unsigned long uclamp_task_util(struct task_struct *p, > > - unsigned long uclamp_min, > > - unsigned long uclamp_max) > > -{ > > - return task_util_est(p); > > -} > > -#endif > > - > > static inline void util_est_enqueue(struct cfs_rq *cfs_rq, > > struct task_struct *p) > > { > > @@ -7588,7 +7572,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) > > target = prev_cpu; > > > > sync_entity_load_avg(&p->se); > > - if (!uclamp_task_util(p, p_util_min, p_util_max)) > > + if (!task_util_est(p) && p_util_min == 0) > > goto unlock; > > > > eenv_task_busy_time(&eenv, p, prev_cpu); > > -- > > 2.25.1 > >
| |