Re: load balancing regression since commit 367456c7

From: Peter Zijlstra
Date: Fri Apr 20 2012 - 12:54:01 EST


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?

If it goes away, its the cgroup balancing, if its still there its
elsewhere.

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