Re: [patch v5 14/15] sched: power aware load balance

Alex Shi
2013-03-30T14:05:09Z

On 03/30/2013 07:25 PM, Preeti U Murthy wrote:
>> > I still give the rq->util weight even the nr_running is 0, because some
>> > transitory tasks may actived on the cpu, but just missed on balancing point.
>> >
>> > I just wondering that forgetting rq->util when nr_running = 0 is the
>> > real root cause if your finding is just on VM and without fixed VCPU to
>> > CPU pin.
> I find the same situation on a physical machine too. On a 2 socket, 4
> core machine as well. In fact, using trace_printks in the load balancing
> part, I could find that the reason that the load was not getting
> consolidated onto a socket was because the rq->util of a run-queue with
> no processes on it, had not decayed to 0, which is why it would consider
> the socket as overloaded and would rule out power aware balancing.All
> this was on a physical machine.

Consider of this situation, we may stop account the rq->util when
nr_running is zero. Tasks will be a bit more compact. but anyway, that's
powersaving policy.

--
Thanks
Alex