Subject: Re: Patch "sched: Give CPU bound RT tasks preference" has been
 added to the 2.6.32-longterm tree
From: Mike Galbraith <efault@gmx.de>
To: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Jiri Slaby <jirislaby@gmail.com>, Ingo Molnar <mingo@elte.hu>,
        Steven Rostedt <rostedt@goodmis.org>, gregkh@suse.de,
        srostedt <srostedt@redhat.com>, a.p.zijlstra@chello.nl,
        ghaskins@novell.com, stable@kernel.org, stable-commits@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>
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Date: Thu, 17 Feb 2011 10:41:08 +0100
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On Thu, 2011-02-17 at 08:52 +0100, Stefan Richter wrote:
> On Feb 17 Mike Galbraith wrote:
> > On Wed, 2011-02-16 at 15:29 +0100, Stefan Richter wrote:
> > > Jiri,
> > > if the desire is to improve performance of existing features (and maybe
> > > add this and that little feature that looks attractive), while at the same
> > > time you want
> > >   - experts to have looked at these improvements,
> > >   - packagers to avoid duplicate work,
> > >   - keep the number of local patches in check,
> > > then the solution is to /stay close enough to the mainline/.
> 
> [By which I meant updating, not backporting.]

[but you know that ain't an option too]

> > People are fixing this and that in their enterprise kernels privately
> > every day.  The only difference between that, and pushing baked fixes
> > back is that pushing to stable is visible.  I strongly suspect that
> > there are just tons of mainline backports sitting in each and every
> > enterprise tree in existence.
> 
> 'Visible' = the change which was an important performance improvement or
> outright fix at site A (and a nice-to-have improvement on sites B...X)
> eventually exhibits a regression at site Y.

Known bugs are stable bugs, known performance problems are stable
performance problems is the only answer to that.  Leaving them as is
does remove risk of a customer satisfaction delta.. but..  

But whatever.  Yeah, I understand that it's a sticky wicket.

	-Mike

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