Re: load balancing regression since commit 367456c7

From: Tim Chen
Date: Fri Apr 20 2012 - 13:13:36 EST


On Fri, 2012-04-20 at 18:53 +0200, Peter Zijlstra wrote:
> On Fri, 2012-04-20 at 09:40 -0700, Tim Chen wrote:
> > We also do not see regression for hackbench on WSM-EP, but only
> > on machines with Sandy-Bridge EP (2 socket, 8 cores/socket, HT enabled).
>
> Argh, Suresh, any idea what could be different and relevant to this
> issue between WSM and SNB -EP ?
>
> Tim, can you see the problem on the desktop SNB part? That's the only
> SNB I have available.
>
> > We are not running hackbench in cgroup for this test.
> >
> > The Sandy Bridge EP machines installed has FC16, so I think it uses
> > systemd. The machine on our WSM EP has FC15, which also has systemd.
>
> Ah, but your .config has:
>
> CONFIG_CGROUP_SCHED=y
> CONFIG_SCHED_AUTOGROUP=y
>
> and systemd, when cpu-cgroup is available, will automagically use it.
>
> Could you disable those two CONFIG knobs and see if it persists?
>

Turning those off did recover the regression.

Tim

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