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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [Regression] 2.6.24-git9: RT sched mishandles artswrapper (bisected)
Date: Wed, 6 Feb 2008 23:18:27 +0100
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Cc: Dmitry Adamushko <dmitry.adamushko@gmail.com>, Ingo Molnar <mingo@elte.hu>,
       Andrew Morton <akpm@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>,
       Steven Rostedt <rostedt@goodmis.org>
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On Wednesday, 6 of February 2008, Peter Zijlstra wrote:
> 
> On Wed, 2008-02-06 at 22:50 +0100, Rafael J. Wysocki wrote:
> > On Wednesday, 6 of February 2008, Peter Zijlstra wrote:
> 
> > > Well, that whole queue.
> > 
> > It doesn't compile for me.
> 
> I did solve some compile issues since posting, Ingo should have the
> compiling version in sched-devel soonish (don't know if he pushed it
> already).

Can you point me to the cleaned up version, please?

> > > Your test program just failed to obtain realtime scheduling
> > 
> > Well, it shouldn't.  The expected result is to obtain realtime scheduling
> > or we will break existing setups.
> 
> Thats a case of wrong expectations in my book. You enabled group
> scheduling and hence behaviour changes.

So, I'd have to unset FAIR_GROUP_SCHED to obtain the previous behavior?

> There is just nothing much one can do about it, if you don't assign bandwidth
> to a group, it won't be able to run anything. Better to refuse to run, than to sit
> idle, right? 

As a general rule, probably yes.

> But I appreciate the situation, therefore I made the whole rt-group
> scheduling a separate .config option (which defaults to n)

Which is introduced by the new patches, isn't it?