From: Vincent Guittot <vincent.guittot@linaro.org>
To: rjw@rjwysocki.net, viresh.kumar@linaro.org, mingo@redhat.com,
peterz@infradead.org, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Subject: [PATCH] sched/fair: remove redundant call to cpufreq_update_util
Date: Wed, 15 Jan 2020 11:20:20 +0100 [thread overview]
Message-ID: <1579083620-24943-1-git-send-email-vincent.guittot@linaro.org> (raw)
With commit bef69dd87828 ("sched/cpufreq: Move the cfs_rq_util_change() call to cpufreq_update_util()")
update_load_avg() has become the central point for calling cpufreq (not
including the update of blocked load). This change helps to simplify
further the number of call to cpufreq_update_util() and to remove last
redundant ones. With update_load_avg(), we are now sure that
cpufreq_update_util() will be called after every task attachment to a
cfs_rq and especially after propagating this event down to the util_avg of
the root cfs_rq, which is the level that is used by cpufreq governors like
schedutil to set the frequency of a CPU.
The SCHED_CPUFREQ_MIGRATION flag forces an early call to cpufreq when the
migration happens in a cgroup whereas util_avg of root cfs_rq is not yet
updated and this call is duplicated with the one that happens immediately
after when the migration event reaches the root cfs_rq. The dedicated flag
SCHED_CPUFREQ_MIGRATION is now useless and can be removed. The interface of
attach_entity_load_avg() can also be simplified accordingly.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
include/linux/sched/cpufreq.h | 1 -
kernel/sched/fair.c | 14 +++++++-------
2 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h
index cc6bcc1e96bc..3ed5aa18593f 100644
--- a/include/linux/sched/cpufreq.h
+++ b/include/linux/sched/cpufreq.h
@@ -9,7 +9,6 @@
*/
#define SCHED_CPUFREQ_IOWAIT (1U << 0)
-#define SCHED_CPUFREQ_MIGRATION (1U << 1)
#ifdef CONFIG_CPU_FREQ
struct cpufreq_policy;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2d170b5da0e3..023aa42aaac7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -801,7 +801,7 @@ void post_init_entity_util_avg(struct task_struct *p)
* For !fair tasks do:
*
update_cfs_rq_load_avg(now, cfs_rq);
- attach_entity_load_avg(cfs_rq, se, 0);
+ attach_entity_load_avg(cfs_rq, se);
switched_from_fair(rq, p);
*
* such that the next switched_to_fair() has the
@@ -3114,7 +3114,7 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags)
{
struct rq *rq = rq_of(cfs_rq);
- if (&rq->cfs == cfs_rq || (flags & SCHED_CPUFREQ_MIGRATION)) {
+ if (&rq->cfs == cfs_rq) {
/*
* There are a few boundary cases this might miss but it should
* get called often enough that that should (hopefully) not be
@@ -3520,7 +3520,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
* Must call update_cfs_rq_load_avg() before this, since we rely on
* cfs_rq->avg.last_update_time being current.
*/
-static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
+static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
@@ -3556,7 +3556,7 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
add_tg_cfs_propagate(cfs_rq, se->avg.load_sum);
- cfs_rq_util_change(cfs_rq, flags);
+ cfs_rq_util_change(cfs_rq, 0);
trace_pelt_cfs_tp(cfs_rq);
}
@@ -3614,7 +3614,7 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
*
* IOW we're enqueueing a task on a new CPU.
*/
- attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION);
+ attach_entity_load_avg(cfs_rq, se);
update_tg_load_avg(cfs_rq, 0);
} else if (decayed) {
@@ -3871,7 +3871,7 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
static inline void remove_entity_load_avg(struct sched_entity *se) {}
static inline void
-attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) {}
+attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
static inline void
detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
@@ -10439,7 +10439,7 @@ static void attach_entity_cfs_rq(struct sched_entity *se)
/* Synchronize entity with its cfs_rq */
update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD);
- attach_entity_load_avg(cfs_rq, se, 0);
+ attach_entity_load_avg(cfs_rq, se);
update_tg_load_avg(cfs_rq, false);
propagate_entity_cfs_rq(se);
}
--
2.7.4
next reply other threads:[~2020-01-15 10:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 10:20 Vincent Guittot [this message]
2020-01-15 10:28 ` [PATCH] sched/fair: remove redundant call to cpufreq_update_util Rafael J. Wysocki
2020-01-15 15:35 ` Peter Zijlstra
2020-01-15 20:20 ` Dietmar Eggemann
2020-01-16 7:52 ` Vincent Guittot
2020-01-17 10:08 ` [tip: sched/core] sched/fair: Remove redundant call to cpufreq_update_util() tip-bot2 for Vincent Guittot
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=1579083620-24943-1-git-send-email-vincent.guittot@linaro.org \
--to=vincent.guittot@linaro.org \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rjw@rjwysocki.net \
--cc=rostedt@goodmis.org \
--cc=viresh.kumar@linaro.org \
/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).