Re: [PATCH 0/6] sched/fair: Compute capacity invariant load/utilization tracking

From: Peter Zijlstra
Date: Mon Sep 07 2015 - 08:42:43 EST

On Mon, Aug 31, 2015 at 11:24:49AM +0200, Peter Zijlstra wrote:

> A quick run here gives:
> IVB-EP (2*20*2):

As noted by someone; that should be 2*10*2, for a total of 40 cpus in
this machine.

> perf stat --null --repeat 10 -- perf bench sched messaging -g 50 -l 5000
> Before: After:
> 5.484170711 ( +- 0.74% ) 5.590001145 ( +- 0.45% )
> Which is an almost 2% slowdown :/
> I've yet to look at what happens.

OK, so it appears this is link order nonsense. When I compared profiles
between the series, the one function that had significant change was
skb_release_data(), which doesn't make much sense.

If I do a 'make clean' in front of each build, I get a repeatable
improvement with this patch set (although how much of that is due to the
patches itself or just because of code movement is as yet undetermined).

I'm of a mind to apply these patches; with two patches on top, which
I'll post shortly.
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