Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenariosin PLE handler

[Raghavendra K T]

On 09/24/2012 07:24 PM, Peter Zijlstra wrote:
> On Mon, 2012-09-24 at 18:59 +0530, Raghavendra K T wrote:
> > However Rik had a genuine concern in the cases where runqueue is not
> > equally distributed and lockholder might actually be on a different run
> > queue but not running.
>
> Load should eventually get distributed equally -- that's what the
> load-balancer is for -- so this is a temporary situation.
>
> We already try and favour the non running vcpu in this case, that's what
> yield_to_task_fair() is about. If its still not eligible to run, tough
> luck.

Yes, I agree.

> > Do you think instead of using rq->nr_running, we could get a global
> > sense of load using avenrun (something like avenrun/num_onlinecpus)
>
> To what purpose? Also, global stuff is expensive, so you should try and
> stay away from it as hard as you possibly can.

Yes, that concern only had made me to fall back to rq->nr_running.

Will come back with the result soon.

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