Re: sysbench throughput degradation in 4.13+

From: Rik van Riel
Date: Tue Oct 03 2017 - 12:02:51 EST


On Tue, 2017-10-03 at 10:39 +0200, Peter Zijlstra wrote:
> On Mon, Oct 02, 2017 at 11:53:12PM +0100, Matt Fleming wrote:
> > On Wed, 27 Sep, at 01:58:20PM, Rik van Riel wrote:
> > >
> > > I like the simplicity of your approach!ÂÂI hope it does not break
> > > stuff like netperf...
> > >
> > > I have been working on the patch below, which is much less
> > > optimistic
> > > about when to do an affine wakeup than before.
> >
> > Running netperf for this patch and Peter's patch shows that Peter's
> > comes out on top, with scores pretty close to v4.12 in most places
> > on
> > my 2-NUMA node 48-CPU Xeon box.
> >
> > I haven't dug any further into why v4.13-peterz+ is worse than
> > v4.12,
> > but I will next week.
>
> So I was waiting for Rik, who promised to run a bunch of NUMA
> workloads
> over the weekend.
>
> The trivial thing regresses a wee bit on the overloaded case, I've
> not
> yet tried to fix it.

In Jirka's tests, your simple patch also came out
on top.

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