From: Mel Gorman <mgorman@suse.de>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: huang ying <huang.ying.caritas@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
jhladky@redhat.com, lvenanci@redhat.com,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH -mm] autonuma: Fix scan period updating
Date: Fri, 12 Jul 2019 13:50:47 +0100 [thread overview]
Message-ID: <20190712125047.GL13484@suse.de> (raw)
In-Reply-To: <87d0ifwmu2.fsf@yhuang-dev.intel.com>
On Fri, Jul 12, 2019 at 06:48:05PM +0800, Huang, Ying wrote:
> > Ordinarily I would hope that the patch was motivated by observed
> > behaviour so you have a metric for goodness. However, for NUMA balancing
> > I would typically run basic workloads first -- dbench, tbench, netperf,
> > hackbench and pipetest. The objective would be to measure the degree
> > automatic NUMA balancing is interfering with a basic workload to see if
> > they patch reduces the number of minor faults incurred even though there
> > is no NUMA balancing to be worried about. This measures the general
> > overhead of a patch. If your reasoning is correct, you'd expect lower
> > overhead.
> >
> > For balancing itself, I usually look at Andrea's original autonuma
> > benchmark, NAS Parallel Benchmark (D class usually although C class for
> > much older or smaller machines) and spec JBB 2005 and 2015. Of the JBB
> > benchmarks, 2005 is usually more reasonable for evaluating NUMA balancing
> > than 2015 is (which can be unstable for a variety of reasons). In this
> > case, I would be looking at whether the overhead is reduced, whether the
> > ratio of local hits is the same or improved and the primary metric of
> > each (time to completion for Andrea's and NAS, throughput for JBB).
> >
> > Even if there is no change to locality and the primary metric but there
> > is less scanning and overhead overall, it would still be an improvement.
>
> Thanks a lot for your detailed guidance.
>
No problem.
> > If you have trouble doing such an evaluation, I'll queue tests if they
> > are based on a patch that addresses the specific point of concern (scan
> > period not updated) as it's still not obvious why flipping the logic of
> > whether shared or private is considered was necessary.
>
> I can do the evaluation, but it will take quite some time for me to
> setup and run all these benchmarks. So if these benchmarks have already
> been setup in your environment, so that your extra effort is minimal, it
> will be great if you can queue tests for the patch. Feel free to reject
> me for any inconvenience.
>
They're not setup as such, but my testing infrastructure is heavily
automated so it's easy to do and I think it's worth looking at. If you
update your patch to target just the scan period aspects, I'll queue it
up and get back to you. It usually takes a few days for the automation
to finish whatever it's doing and pick up a patch for evaluation.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2019-07-12 12:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 2:56 [PATCH -mm] autonuma: Fix scan period updating Huang Ying
2019-06-24 14:09 ` Mel Gorman
2019-06-25 13:23 ` huang ying
2019-07-03 9:17 ` Mel Gorman
2019-07-04 0:32 ` Huang, Ying
2019-07-12 8:27 ` Mel Gorman
2019-07-12 10:48 ` Huang, Ying
2019-07-12 12:50 ` Mel Gorman [this message]
2019-07-15 8:08 ` Huang, Ying
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