linux-kernel - Re: [RFC PATCH 00/11] Reconcile NUMA balancing decisions with the load balancer

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Date:   Wed, 12 Feb 2020 17:13:55 +0100
From:   Vincent Guittot <vincent.guittot@...aro.org>
To:     Mel Gorman <mgorman@...hsingularity.net>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>,
        Valentin Schneider <valentin.schneider@....com>,
        Phil Auld <pauld@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 00/11] Reconcile NUMA balancing decisions with the
 load balancer

On Wed, 12 Feb 2020 at 16:48, Mel Gorman <mgorman@...hsingularity.net> wrote:
>
> On Wed, Feb 12, 2020 at 02:22:03PM +0100, Vincent Guittot wrote:
> > Hi Mel,
> >
> > On Wed, 12 Feb 2020 at 10:36, Mel Gorman <mgorman@...hsingularity.net> wrote:
> > >
> > > The NUMA balancer makes placement decisions on tasks that partially
> > > take the load balancer into account and vice versa but there are
> > > inconsistencies. This can result in placement decisions that override
> > > each other leading to unnecessary migrations -- both task placement and
> > > page placement. This is a prototype series that attempts to reconcile the
> > > decisions. It's a bit premature but it would also need to be reconciled
> > > with Vincent's series "[PATCH 0/4] remove runnable_load_avg and improve
> > > group_classify"
> > >
> > > The first three patches are unrelated and are either pending in tip or
> > > should be but they were part of the testing of this series so I have to
> > > mention them.
> > >
> > > The fourth and fifth patches are tracing only and was needed to get
> > > sensible data out of ftrace with respect to task placement for NUMA
> > > balancing. Patches 6-8 reduce overhead and reduce the changes of NUMA
> > > balancing overriding itself. Patches 9-11 try and bring the CPU placement
> > > decisions of NUMA balancing in line with the load balancer.
> >
> > Don't know if it's only me but I can't find patches 9-11 on mailing list
> >
>
> I think my outgoing SMTP must have decided I was spamming. I tried
> resending just those patches.

I received them.
Thanks

>
> At the moment, I'm redoing a series in top of tip taking the tracing
> patches, yours on top (for testing) and the minor optimisations to see
> what that gets me.  The reconcilation between NUMA balancing and load
> balancing (patches 9-11) can be redone on top if the rest look ok.
>
> --
> Mel Gorman
> SUSE Labs