Messages in this thread | | | Subject | Re: [PATCH] sched: select 'idle' cfs_rq per task-group to prevent tg-internal imbalance | From | Mike Galbraith <> | Date | Thu, 03 Jul 2014 05:51:02 +0200 |
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On Wed, 2014-07-02 at 10:47 -0400, Rik van Riel wrote: > On 07/01/2014 04:38 AM, Michael wang wrote: > > On 07/01/2014 04:20 PM, Peter Zijlstra wrote: > > [snip] > >>> > >>> Just wondering could we make this another scheduler feature? > >> > >> No; sched_feat() is for debugging, BIG CLUE: its guarded by > >> CONFIG_SCHED_DEBUG, anybody using it in production or anywhere else is > >> broken. > >> > >> If people are using it, I should remove or at least randomize the > >> interface. > > > > Fair enough... but is there any suggestions on how to handle this issue? > > > > Currently when dbench running with stress, it could only gain one CPU, > > and cpu-cgroup cpu.shares is meaningless, is there any good methods to > > address that? > > select_idle_sibling will iterate over all of the CPUs > in an LLC domain if there is no idle cpu in the domain. > > I suspect it would not take much extra code to track > down the idlest CPU in the LLC domain, and make sure to > schedule tasks there, in case no completely idle CPU > was found. > > Are there any major problems with that thinking?
That's full wake balance.. if that was cheap, select_idle_sibling() would not exist.
-Mike
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