Re: [PATCH v4 6/7] sched: add function nr_running_cpu to expose number of tasks running on cpu

[Tim Chen]

On Tue, 2014-07-15 at 14:07 +0200, Peter Zijlstra wrote:
> On Tue, Jul 15, 2014 at 11:50:45AM +0200, Peter Zijlstra wrote:
> > So you already have an idle notifier (which is x86 only, we should fix
> > that I suppose), and you then double check there really isn't anything
> > else running.
> 
> Note that we've already done a large part of the expense of going idle
> by the time we call that idle notifier -- in specific, we've
> reprogrammed the clock to stop the tick.
> 
> Its really wasteful to then generate work again, which means we have to
> again reprogram the clock etc.

Will try another version of the patch without using the idle notifier.

Tim

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