Re: [PATCH] sched: check pinned tasks before nohz balance, linux-4.2-rc5

[Peter Zijlstra]

On Wed, Aug 05, 2015 at 05:14:34PM +0200, Uladzislau Rezki wrote:
> While investigating âload balancerâ logic, I run into interesting
> behavior related
> to affinity and NO_HZ idle balance. Basically saying if there are two
> tasks running
> in certain rq and one of them is pinned/affined, then scheduler will
> trigger load
> balance on power collapsed core via soft irq.
> 
> The corner case here is it may fail to unbalance because of affinity, as a
> result core that has two tasks will interrupt any found idle one each its timer
> tick, what can lead to wasting of power, especially in mobile area, what is
> our case.
> 
> Do you have any concern with provided patch?

Yeah, I should go fix the set_cpus_allowed rework :/

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