From: Vincent Guittot <vincent.guittot@linaro.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Ingo Molnar <mingo@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
linux-kernel@vger.kernel.org, Xuewen Yan <xuewen.yan94@gmail.com>,
Wei Wang <wvw@google.com>,
Jonathan JMChen <Jonathan.JMChen@mediatek.com>,
Hank <han.lin@mediatek.com>
Subject: Re: [PATCH 2/7] sched/uclamp: Make task_fits_capacity() use util_fits_cpu()
Date: Fri, 22 Jul 2022 10:19:13 +0200 [thread overview]
Message-ID: <20220722081913.GA6045@vingu-book> (raw)
In-Reply-To: <20220721142949.fqmabrjwylkuoltw@wubuntu>
Le jeudi 21 juil. 2022 à 15:29:49 (+0100), Qais Yousef a écrit :
> On 07/12/22 11:48, Qais Yousef wrote:
> > On 07/11/22 15:09, Vincent Guittot wrote:
> > > On Wed, 29 Jun 2022 at 21:48, Qais Yousef <qais.yousef@arm.com> wrote:
> >
[...]
> > > > @@ -9108,7 +9125,7 @@ static inline void update_sg_wakeup_stats(struct sched_domain *sd,
> > > >
> > > > /* Check if task fits in the group */
> > > > if (sd->flags & SD_ASYM_CPUCAPACITY &&
> > > > - !task_fits_capacity(p, group->sgc->max_capacity)) {
> > > > + !task_fits_cpu(p, group->sgc->max_capacity_cpu)) {
> > >
> > > All the changes and added complexity above for this line. Can't you
> > > find another way ?
> >
> > You're right, I might have got carried away trying to keep the logic the same.
> >
> > Can we use group->asym_prefer_cpu or pick a cpu from group->sgc->cpumask
> > instead?
> >
> > I'll dig more into it anyway and try to come up with simpler alternative.
>
> Actually we can't.
>
> I can keep the current {max,min}_capacity field and just add the new
> {max,min}_capacity_cpu and use them where needed. Should address your concerns
> this way? That was actually the first version of the code, but then it seemed
> redundant to keep both {max,min}_capacity and {max,min}_capacity_cpu.
>
> OR
>
> I can add a new function to search for max spare capacity cpu in the group.
>
> Preference?
>
Isn't the below enough and much simpler ?
[PATCH] sched/uclamp: Make task_fits_capacity() use util_fits_cpu()
So that the new uclamp rules in regard to migration margin and capacity
pressure are taken into account correctly.
---
kernel/sched/fair.c | 25 +++++++++++++++----------
kernel/sched/sched.h | 9 +++++++++
2 files changed, 24 insertions(+), 10 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5eecae32a0f6..3e0c7cc490be 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4317,10 +4317,12 @@ static inline int util_fits_cpu(unsigned long util,
return fits;
}
-static inline int task_fits_capacity(struct task_struct *p,
- unsigned long capacity)
+static inline int task_fits_cpu(struct task_struct *p, int cpu)
{
- return fits_capacity(uclamp_task_util(p), capacity);
+ unsigned long uclamp_min = uclamp_eff_value(p, UCLAMP_MIN);
+ unsigned long uclamp_max = uclamp_eff_value(p, UCLAMP_MAX);
+ unsigned long util = task_util_est(p);
+ return util_fits_cpu(util, uclamp_min, uclamp_max, cpu);
}
static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
@@ -4333,7 +4335,7 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
return;
}
- if (task_fits_capacity(p, capacity_of(cpu_of(rq)))) {
+ if (task_fits_cpu(p, cpu_of(rq))) {
rq->misfit_task_load = 0;
return;
}
@@ -8104,7 +8106,7 @@ static int detach_tasks(struct lb_env *env)
case migrate_misfit:
/* This is not a misfit task */
- if (task_fits_capacity(p, capacity_of(env->src_cpu)))
+ if (task_fits_cpu(p, env->src_cpu))
goto next;
env->imbalance = 0;
@@ -9085,6 +9087,10 @@ static inline void update_sg_wakeup_stats(struct sched_domain *sd,
memset(sgs, 0, sizeof(*sgs));
+ /* Assume that task can't fit any CPU of the group */
+ if (sd->flags & SD_ASYM_CPUCAPACITY)
+ sgs->group_misfit_task_load = 0;
+
for_each_cpu(i, sched_group_span(group)) {
struct rq *rq = cpu_rq(i);
unsigned int local;
@@ -9104,12 +9110,11 @@ static inline void update_sg_wakeup_stats(struct sched_domain *sd,
if (!nr_running && idle_cpu_without(i, p))
sgs->idle_cpus++;
- }
+ /* Check if task fits in the CPU */
+ if (sd->flags & SD_ASYM_CPUCAPACITY &&
+ task_fits_cpu(p, i))
+ sgs->group_misfit_task_load = 0;
- /* Check if task fits in the group */
- if (sd->flags & SD_ASYM_CPUCAPACITY &&
- !task_fits_capacity(p, group->sgc->max_capacity)) {
- sgs->group_misfit_task_load = 1;
}
sgs->group_capacity = group->sgc->capacity;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 02c970501295..3292ad2db4ac 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2988,6 +2988,15 @@ static inline bool uclamp_is_used(void)
return static_branch_likely(&sched_uclamp_used);
}
#else /* CONFIG_UCLAMP_TASK */
+static inline unsigned long uclamp_eff_value(struct task_struct *p,
+ enum uclamp_id clamp_id)
+{
+ if (clamp_id == UCLAMP_MIN)
+ return 0;
+
+ return SCHED_CAPACITY_SCALE;
+}
+
static inline
unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
struct task_struct *p)
--
2.17.1
>
> Thanks!
>
> --
> Qais Yousef
next prev parent reply other threads:[~2022-07-22 8:19 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-29 19:46 [PATCH 0/7] Fix relationship between uclamp and fits_capacity() Qais Yousef
2022-06-29 19:46 ` [PATCH 1/7] sched/uclamp: Fix relationship between uclamp and migration margin Qais Yousef
2022-07-11 12:36 ` Vincent Guittot
2022-07-12 10:23 ` Qais Yousef
2022-07-12 13:21 ` Vincent Guittot
2022-07-12 14:20 ` Qais Yousef
2022-07-13 12:39 ` Vincent Guittot
2022-07-15 10:37 ` Qais Yousef
2022-07-20 7:29 ` Vincent Guittot
2022-07-21 14:04 ` Qais Yousef
2022-07-22 15:13 ` Vincent Guittot
2022-07-27 16:08 ` Qais Yousef
2022-08-04 14:59 ` Qais Yousef
2022-07-20 7:17 ` Xuewen Yan
2022-07-21 10:24 ` Qais Yousef
2022-07-25 11:59 ` Xuewen Yan
2022-07-27 16:25 ` Qais Yousef
2022-08-01 2:46 ` Xuewen Yan
2022-08-02 16:22 ` Qais Yousef
2022-06-29 19:46 ` [PATCH 2/7] sched/uclamp: Make task_fits_capacity() use util_fits_cpu() Qais Yousef
2022-07-11 13:09 ` Vincent Guittot
2022-07-12 10:48 ` Qais Yousef
2022-07-21 14:29 ` Qais Yousef
2022-07-22 8:19 ` Vincent Guittot [this message]
2022-07-27 16:05 ` Qais Yousef
2022-08-17 9:48 ` Vincent Guittot
2022-07-20 7:23 ` Xuewen Yan
2022-07-21 14:11 ` Qais Yousef
2022-06-29 19:46 ` [PATCH 3/7] sched/uclamp: Fix fits_capacity() check in feec() Qais Yousef
2022-07-20 7:30 ` Xuewen Yan
2022-07-21 14:19 ` Qais Yousef
2022-06-29 19:46 ` [PATCH 4/7] sched/uclamp: Make select_idle_capacity() use util_fits_cpu() Qais Yousef
2022-06-29 19:46 ` [PATCH 5/7] sched/uclamp: Make asym_fits_capacity() " Qais Yousef
2022-06-29 19:46 ` [PATCH 6/7] sched/uclamp: Make cpu_overutilized() " Qais Yousef
2022-06-29 19:46 ` [PATCH 7/7] sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition Qais Yousef
2022-07-20 7:39 ` Xuewen Yan
2022-07-21 14:24 ` Qais Yousef
2022-07-22 1:09 ` Xuewen Yan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220722081913.GA6045@vingu-book \
--to=vincent.guittot@linaro.org \
--cc=Jonathan.JMChen@mediatek.com \
--cc=dietmar.eggemann@arm.com \
--cc=han.lin@mediatek.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=qais.yousef@arm.com \
--cc=wvw@google.com \
--cc=xuewen.yan94@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).