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

From: Alex Shi
Date: Thu Mar 21 2013 - 05:27:22 EST

On 03/21/2013 04:41 PM, Preeti U Murthy wrote:
>> >
> Yes, I did find this behaviour on a 2 socket, 8 core machine very
> consistently.
> rq->util cannot go to 0, after it has begun accumulating load right?
> Say a load was running on a runqueue which had its rq->util to be at
> 100%. After the load finishes, the runqueue goes idle. For every
> scheduler tick, its utilisation decays. But can never become 0.
> rq->util = rq->avg.runnable_avg_sum/rq->avg.runnable_avg_period

did you close all of background system services?
In theory the rq->avg.runnable_avg_sum should be zero if there is no
task a bit long, otherwise there are some bugs in kernel. Could you
check the value under /proc/sched_debug?

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