Re: [RFC PATCH] sched/util_est: Do not sub the delayed-task's util-est

[Hongyan Xia]

On 21/03/2025 06:44, Xuewen Yan wrote:
> Hi hongyan
>
> On Wed, Mar 19, 2025 at 9:33 PM Dietmar Eggemann
> <dietmar.eggemann@xxxxxxx> wrote:
> > On 14/03/2025 10:09, Xuewen Yan wrote:
> > > In cpu_util_without, When the task is in rq, we should
> > > sub the task's util_est, however, the delayed_task->on_rq
> > > is true, however, the delayed_task's util had been sub
> > > when sleep, so there is no need to sub the delayed task's
> > > util-est. So add the checking of delayed-task.
> > >
> > > On the other hand, as said in [1], the logic of util_est's
> > > enqueue/dequeue could be simplified.
> > > So simplify it by aligning with the conditions of uclamp.
> >
> > This flag simplification looks good to me.
> >
> > IMHO, you should submit this with the uclamp change so that we can call
> > uclamp_rq_inc() before p->sched_class->enqueue_task(). To make sure the
> > task which is enqueued with 'flags & ENQUEUE_DELAYED' is considered for
> > cpufreq_update_util() in enqueue_task_fair() (Hongyan's finding in
> > https://lkml.kernel.org/r/84441660bef0a5e67fd09dc3787178d0276dad31.1740664400.git.hongyan.xia2@xxxxxxx)
> >
> > I would prefer the less invasive fix you presented here:
> >
> > https://lkml.kernel.org/r/CAB8ipk9LpbiUDnbcV6+59+Sa=Ai7tFzO===mpLD3obNdV4=J-A@xxxxxxxxxxxxxx
> >
> > since uclamp is already a core thing (fair + rt), it works for current
> > max aggregation and it's less invasive.
>
> Since the uclamp's enqueue is affecting performance, could we fix the
> uclamp-enqueue issue first?
> Need I to send the patch-v2 base the
> https://lore.kernel.org/all/CAB8ipk9LpbiUDnbcV6+59+Sa=Ai7tFzO===mpLD3obNdV4=J-A@xxxxxxxxxxxxxx/T/#mb32d7675beda5cadc35a3c04cddebc39580c718b
> ?
> As for whether we need to distinguish sched-class, can we discuss that later?
>
> Thanks!

Sure.

> [...]