Re: [PATCH] Avoid moving tasks when a schedule can be made.

[Nick Piggin]

Nick Piggin wrote:
> Steven Rostedt wrote:
>
> > No real work is lost.  This is a loop that individually pulls tasks.  So
> > the bail only stops the work of looking for more tasks to pull and we
> > don't lose the tasks that have already been pulled.
>
> Once we've gone to the trouble of deciding which tasks to move and how
> many (and the estimate should be very conservative), and locked the source
> and destination runqueues, it is a very good idea to follow up with our
> threat of actually moving the tasks rather than bail out early.

Oh, I forgot: Ingo once introduced some code to bail early (though for
different reasons and under different conditions), and this actually
was found to cause significant regressions in some database workloads.
So it is not a nice thing to tinker with unless there is good reason.

--
SUSE Labs, Novell Inc.
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