Messages in this thread | | | Date | Thu, 21 Feb 2013 13:21:42 +0800 | From | Michael Wang <> | Subject | Re: [RFC PATCH v3 0/3] sched: simplify the select_task_rq_fair() |
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On 02/20/2013 10:05 PM, Mike Galbraith wrote: > On Wed, 2013-02-20 at 14:32 +0100, Peter Zijlstra wrote: >> On Wed, 2013-02-20 at 11:49 +0100, Ingo Molnar wrote: >> >>> The changes look clean and reasoable, >> >> I don't necessarily agree, note that O(n^2) storage requirement that >> Michael failed to highlight ;-) > > (yeah, I mentioned that needs to shrink.. a lot)
Exactly, and I'm going to apply the suggestion now :)
> >>> any ideas exactly *why* it speeds up? >> >> That is indeed the most interesting part.. There's two parts to >> select_task_rq_fair(), the 'regular' affine wakeup path, and the >> fork/exec find_idlest_goo() path. At the very least we need to quantify >> which of these two parts contributes most to the speedup. >> >> In the power balancing discussion we already noted that the >> find_idlest_goo() is in need of attention. > > Yup, even little stuff like break off the search when load is zero..
Agree, searching in a bunch of idle cpus and their subsets doesn't make sense...
Regards, Michael Wang
> unless someone is planning on implementing anti-idle 'course ;-) > > -Mike > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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