lkml.org 
[lkml]   [2020]   [Aug]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] sched/fair: avoid vruntime compensation for SCHED_IDLE task
On Thu, 20 Aug 2020 at 20:51, Vincent Guittot
<vincent.guittot@linaro.org> wrote:
>
> On Thu, 20 Aug 2020 at 14:00, Jiang Biao <benbjiang@gmail.com> wrote:
> >
> > From: Jiang Biao <benbjiang@tencent.com>
> >
> > Vruntime compensation has been down in place_entity() to
> > boot the waking procedure for fair tasks. There is no need to
>
> s/boot/boost/ ?
Yes. -:)
>
> > do that for SCHED_IDLE task actually.
> >
> > Not compensating vruntime for SCHED_IDLE task could make
> > SCHED_IDLE task more harmless for normal tasks.
> >
> > Signed-off-by: Jiang Biao <benbjiang@tencent.com>
> > ---
> > kernel/sched/fair.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 1a68a0536add..adff77676a0a 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -4115,7 +4115,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
> > vruntime += sched_vslice(cfs_rq, se);
> >
> > /* sleeps up to a single latency don't count. */
> > - if (!initial) {
> > + if (!initial && likely(!task_has_idle_policy(task_of(se)))) {
>
> What if se is not a task ?
Is it ok to limit the case to task se, like?
+ if (!initial && likely(!entity_is_task(se) ||
!task_has_idle_policy(task_of(se)))) {

Thx.
Regards,
Jiang
>
> > unsigned long thresh = sysctl_sched_latency;
> >
> > /*
> > --
> > 2.21.0
> >

\
 
 \ /
  Last update: 2020-08-20 16:18    [W:0.092 / U:0.128 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site