Messages in this thread | | | Subject | Re: [RFC PATCH v3 0/3] sched: simplify the select_task_rq_fair() | From | Mike Galbraith <> | Date | Wed, 20 Feb 2013 15:05:19 +0100 |
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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)
> > 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.. unless someone is planning on implementing anti-idle 'course ;-)
-Mike
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