Subject: Re: ppc32: Weird process scheduling behaviour with 2.6.24-rc

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 25 Jan 2008 17:54:42 +1100

On Wed, 2008-01-23 at 13:42 +0100, Peter Zijlstra wrote:
> Another question, do you have:
>   CONFIG_FAIR_GROUP_SCHED=y
> 
> if so, does flipping that off have any effect?

Yes.

Here, I do the test of running 4 times the repro-case provided by Michel
with nice 19 and a dd eating CPU with nice 0.

Without this option, I get the dd at 100% and the nice 19 shells down
below it with whatever is left of the CPUs.

With this option, dd gets about 50% of one CPU and the niced processes
still get most of the time.

Ben.