Messages in this thread | | | From | Xuewen Yan <> | Date | Tue, 29 Jun 2021 11:11:17 +0800 | Subject | Re: [PATCH] sched/uclamp: Fix getting unreasonable ucalmp_max when rq is idle |
| |
+cc Qais, Quentin
Hi Dietmar,
The patch has been around for a long time, and I think it makes sense for EAS. Do you have any suggestions or comments?
Thanks! xuewen
On Fri, Jun 18, 2021 at 3:24 PM Xuewen Yan <xuewen.yan94@gmail.com> wrote: > > From: Xuewen Yan <xuewen.yan@unisoc.com> > > Now in uclamp_rq_util_with(), when the task != NULL, the uclamp_max as following: > uc_rq_max = rq->uclamp[UCLAMP_MAX].value; > uc_eff_max = uclamp_eff_value(p, UCLAMP_MAX); > uclamp_max = max{uc_rq_max, uc_eff_max}; > > Consider the following scenario: > (1)the rq is idle, the uc_rq_max is last task's UCLAMP_MAX; > (2)the p's uc_eff_max < uc_rq_max. > > The result is the uclamp_max = uc_rq_max instead of uc_eff_max, it is unreasonable. > > The scenario often happens in find_energy_efficient_cpu(), when the task has smaller UCLAMP_MAX. > > Inserts whether the rq is idle in the uclamp_rq_util_with(). > > Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com> > --- > kernel/sched/sched.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index a189bec13729..0feef6af89f2 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -2550,7 +2550,10 @@ unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util, > > if (p) { > min_util = max(min_util, uclamp_eff_value(p, UCLAMP_MIN)); > - max_util = max(max_util, uclamp_eff_value(p, UCLAMP_MAX)); > + if (rq->uclamp_flags & UCLAMP_FLAG_IDLE) > + max_util = uclamp_eff_value(p, UCLAMP_MAX); > + else > + max_util = max(max_util, uclamp_eff_value(p, UCLAMP_MAX)); > } > > /* > -- > 2.25.1 >
| |