From: Vincent Guittot <vincent.guittot@linaro.org>
To: 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
Cc: valentin.schneider@arm.com, pauld@redhat.com, hdanton@sina.com,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: [PATCH 4/4 v2] sched/fair: reduce busy load balance interval
Date: Mon, 21 Sep 2020 09:24:24 +0200 [thread overview]
Message-ID: <20200921072424.14813-5-vincent.guittot@linaro.org> (raw)
In-Reply-To: <20200921072424.14813-1-vincent.guittot@linaro.org>
The busy_factor, which increases load balance interval when a cpu is busy,
is set to 32 by default. This value generates some huge LB interval on
large system like the THX2 made of 2 node x 28 cores x 4 threads.
For such system, the interval increases from 112ms to 3584ms at MC level.
And from 228ms to 7168ms at NUMA level.
Even on smaller system, a lower busy factor has shown improvement on the
fair distribution of the running time so let reduce it for all.
Reviewed-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/topology.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 41df62884cea..a3a2417fec54 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1348,7 +1348,7 @@ sd_init(struct sched_domain_topology_level *tl,
*sd = (struct sched_domain){
.min_interval = sd_weight,
.max_interval = 2*sd_weight,
- .busy_factor = 32,
+ .busy_factor = 16,
.imbalance_pct = 117,
.cache_nice_tries = 0,
--
2.17.1
next prev parent reply other threads:[~2020-09-21 7:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 7:24 [PATCH 0/4 v2] sched/fair: Improve fairness between cfs tasks Vincent Guittot
2020-09-21 7:24 ` [PATCH 1/4 v2] sched/fair: relax constraint on task's load during load balance Vincent Guittot
2020-09-23 14:43 ` Valentin Schneider
2020-09-29 7:56 ` [tip: sched/core] sched/fair: Relax " tip-bot2 for Vincent Guittot
2020-09-21 7:24 ` [PATCH 2/4 v2] sched/fair: reduce minimal imbalance threshold Vincent Guittot
2020-09-23 14:43 ` Valentin Schneider
2020-09-29 7:56 ` [tip: sched/core] sched/fair: Reduce " tip-bot2 for Vincent Guittot
2020-09-21 7:24 ` [PATCH 3/4 v2] sched/fair: minimize concurrent LBs between domain level Vincent Guittot
2020-09-23 14:43 ` Valentin Schneider
2020-09-29 7:56 ` [tip: sched/core] sched/fair: Minimize " tip-bot2 for Vincent Guittot
2020-09-21 7:24 ` Vincent Guittot [this message]
2020-09-23 14:43 ` [PATCH 4/4 v2] sched/fair: reduce busy load balance interval Valentin Schneider
2020-09-29 7:56 ` [tip: sched/core] sched/fair: Reduce " tip-bot2 for Vincent Guittot
2020-09-23 15:47 ` [PATCH 0/4 v2] sched/fair: Improve fairness between cfs tasks Mel Gorman
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=20200921072424.14813-5-vincent.guittot@linaro.org \
--to=vincent.guittot@linaro.org \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=hdanton@sina.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=pauld@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=valentin.schneider@arm.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).