From: Vincent Guittot <vincent.guittot@linaro.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched/numa: use runnable_avg to classify node
Date: Tue, 25 Aug 2020 17:52:38 +0200 [thread overview]
Message-ID: <CAKfTPtBfb25L4J2tF-XOXVJSu8-N-dzU3mBdTPVxAtCnUZNfLA@mail.gmail.com> (raw)
In-Reply-To: <20200825135841.GC3033@suse.de>
On Tue, 25 Aug 2020 at 15:58, Mel Gorman <mgorman@suse.de> wrote:
>
> On Tue, Aug 25, 2020 at 02:18:18PM +0200, Vincent Guittot wrote:
> > Use runnable_avg to classify numa node state similarly to what is done for
> > normal load balancer. This helps to ensure that numa and normal balancers
> > use the same view of the state of the system.
> >
> > - large arm64system: 2 nodes / 224 CPUs
> > hackbench -l (256000/#grp) -g #grp
> >
> > grp tip/sched/core +patchset improvement
> > 1 14,008(+/- 4,99 %) 13,800(+/- 3.88 %) 1,48 %
> > 4 4,340(+/- 5.35 %) 4.283(+/- 4.85 %) 1,33 %
> > 16 3,357(+/- 0.55 %) 3.359(+/- 0.54 %) -0,06 %
> > 32 3,050(+/- 0.94 %) 3.039(+/- 1,06 %) 0,38 %
> > 64 2.968(+/- 1,85 %) 3.006(+/- 2.92 %) -1.27 %
> > 128 3,290(+/-12.61 %) 3,108(+/- 5.97 %) 5.51 %
> > 256 3.235(+/- 3.95 %) 3,188(+/- 2.83 %) 1.45 %
> >
>
> Intuitively the patch makes sense but I'm not a fan of using hackbench
> for evaluating NUMA balancing. The tasks are too short-lived and it's
> not sensitive enough to data placement because of the small footprint
> and because hackbench tends to saturate a machine.
>
> As predicting NUMA balancing behaviour in your head can be difficult, I've
> queued up a battery of tests on a few different NUMA machines and will see
> what falls out. It'll take a few days as some of the tests are long-lived.
Thanks for testing Mel
>
> Baseline will be 5.9-rc2 as I haven't looked at the topology rework in
> tip/sched/core and this patch should not be related to it.
looks fine to me
>
> --
> Mel Gorman
> SUSE Labs
next prev parent reply other threads:[~2020-08-25 15:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-25 12:18 [PATCH] sched/numa: use runnable_avg to classify node Vincent Guittot
2020-08-25 13:58 ` Mel Gorman
2020-08-25 15:52 ` Vincent Guittot [this message]
2020-08-27 15:35 ` Mel Gorman
2020-08-27 15:43 ` Vincent Guittot
2020-08-27 18:22 ` Mel Gorman
2020-08-28 6:47 ` Vincent Guittot
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