Re: [PATCH] sched: select 'idle' cfs_rq per task-group to prevent tg-internal imbalance

[Peter Zijlstra]

On Tue, Jul 01, 2014 at 04:38:58PM +0800, 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?

So as far as I understood this is because of 'other' tasks; these other
tasks have never been fully qualified, but I suspect they're workqueue
thingies. One solution would be to have work run in the same cgroup as
the task creating it.

The thing is, this is not a scheduler problem, so we should not fix it
in the scheduler.

Attachment: pgpXJEqHSPCYl.pgp
Description: PGP signature