From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
Phil Auld <pauld@redhat.com>, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Quentin Perret <quentin.perret@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <Morten.Rasmussen@arm.com>,
Hillf Danton <hdanton@sina.com>, Parth Shah <parth@linux.ibm.com>,
Rik van Riel <riel@surriel.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched, fair: Allow a small load imbalance between low utilisation SD_NUMA domains v4
Date: Mon, 20 Jan 2020 22:57:06 +0530 [thread overview]
Message-ID: <20200120172706.GE20112@linux.vnet.ibm.com> (raw)
In-Reply-To: <20200120083354.GT3466@techsingularity.net>
> And this is why I'm curious as to why your workload is affected at all
> because it uses many tasks. I stopped allowing an imbalance for higher
> task counts partially on the basis of your previous report.
>
With this hunk on top of your patch and 5 runs of numa02, there were 0
traces.
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ade7a8dca5e4..7506cf67bde8 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8714,8 +8714,10 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
* the risk that lower domains have to be rebalanced.
*/
imbalance_min = 2;
- if (busiest->sum_nr_running <= imbalance_min)
+ if (busiest->sum_nr_running <= imbalance_min) {
+ trace_printk("Reseting imbalance: busiest->sum_nr_running=%d, local->sum_nr_running=%d\n", busiest->sum_nr_irunning, local->sum_nr_running);
env->imbalance = 0;
+ }
}
return;
perf stat for the 5 iterations this time shows:
77.817 +- 0.995 seconds time elapsed ( +- 1.28% )
which I think is significantly less than last time around.
So I think it may be some other noise that could have contributed to the
jump last time. Also since the time consumption of numa02 is very small, a
small disturbance can show up as a big number from a percentage perspective.
--
Thanks and Regards
Srikar Dronamraju
next prev parent reply other threads:[~2020-01-20 17:27 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 10:13 [PATCH] sched, fair: Allow a small load imbalance between low utilisation SD_NUMA domains v4 Mel Gorman
2020-01-16 16:35 ` Mel Gorman
2020-01-17 13:08 ` Vincent Guittot
2020-01-17 14:15 ` Mel Gorman
2020-01-17 14:32 ` Phil Auld
2020-01-17 14:23 ` Phil Auld
2020-01-17 14:37 ` Valentin Schneider
2020-01-17 13:16 ` Vincent Guittot
2020-01-17 14:26 ` Mel Gorman
2020-01-17 14:29 ` Vincent Guittot
2020-01-17 15:09 ` Vincent Guittot
2020-01-17 15:11 ` Peter Zijlstra
2020-01-17 15:21 ` Phil Auld
2020-01-17 17:56 ` Srikar Dronamraju
2020-01-17 21:58 ` Mel Gorman
2020-01-20 8:09 ` Srikar Dronamraju
2020-01-20 8:33 ` Mel Gorman
2020-01-20 17:27 ` Srikar Dronamraju [this message]
2020-01-20 18:21 ` Mel Gorman
2020-01-21 8:55 ` Srikar Dronamraju
2020-01-21 9:11 ` Mel Gorman
2020-01-21 10:42 ` Peter Zijlstra
2020-01-21 9:59 ` Srikar Dronamraju
2020-01-29 11:32 ` [tip: sched/core] sched/fair: Allow a small load imbalance between low utilisation SD_NUMA domains tip-bot2 for 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=20200120172706.GE20112@linux.vnet.ibm.com \
--to=srikar@linux.vnet.ibm.com \
--cc=Morten.Rasmussen@arm.com \
--cc=dietmar.eggemann@arm.com \
--cc=hdanton@sina.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@techsingularity.net \
--cc=mingo@kernel.org \
--cc=parth@linux.ibm.com \
--cc=pauld@redhat.com \
--cc=peterz@infradead.org \
--cc=quentin.perret@arm.com \
--cc=riel@surriel.com \
--cc=valentin.schneider@arm.com \
--cc=vincent.guittot@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