Re: [tip:sched/core] sched/rt: Reduce rq lock contention by eliminating locking of non-feasible target

[Ben Hutchings]

On Tue, 2015-02-24 at 11:12 -0500, Steven Rostedt wrote:
> On Sun, 1 Feb 2015 09:52:24 -0800
> tip-bot for Tim Chen <tipbot@xxxxxxxxx> wrote:
> 
> > Commit-ID:  80e3d87b2c5582db0ab5e39610ce3707d97ba409
> > Gitweb:     http://git.kernel.org/tip/80e3d87b2c5582db0ab5e39610ce3707d97ba409
> > Author:     Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
> > AuthorDate: Fri, 12 Dec 2014 15:38:12 -0800
> > Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
> > CommitDate: Fri, 30 Jan 2015 19:38:49 +0100
> > 
> > sched/rt: Reduce rq lock contention by eliminating locking of non-feasible target
> > 
> > This patch adds checks that prevens futile attempts to move rt tasks
> > to a CPU with active tasks of equal or higher priority.
> > 
> > This reduces run queue lock contention and improves the performance of
> > a well known OLTP benchmark by 0.7%.
> > 
> > Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> > Cc: Shawn Bohrer <sbohrer@xxxxxxxxxxxxxxx>
> > Cc: Suruchi Kadu <suruchi.a.kadu@xxxxxxxxx>
> > Cc: Doug Nelson<doug.nelson@xxxxxxxxx>
> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > Link: http://lkml.kernel.org/r/1421430374.2399.27.camel@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> 
> I see this has been added to mainline already. I think this should go
> to stable as well. As far back as it applies. I'll even add this to the
> stable-rt if need be. But I rather pull it into stable-rt via the
> stable branches.
[...]

I've queued this up for 3.2, thanks.

Ben.

-- 
Ben Hutchings
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