On Wed, Jun 04, 2014 at 12:52:46PM +0100, Vincent Guittot wrote:

On 4 June 2014 13:23, Morten Rasmussen [off-list ref] wrote:

quoted

I get:

A: 15/40 ms = 37.5%
B: 20/40 ms = 50%

Schedule:

   | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms |
A:   run     rq     run  ----------- sleeping -------------  run
B:   rq      run    rq    run   ---- sleeping -------------  rq

quoted

and CPU runnable will be 60% too

rq->avg.runnable_avg_sum should be 50%. You have two tasks running for
20 ms every 40 ms.

Right?

ok, i see the misunderstood.
it's depends of what we mean by runnable. You take the % of time
whereas i take the runnable_avg_sum/period

Right. There is a difference.

so A is on_rq 15/40 ms = 37.5% of the time which gives a
runnable_avg_sum/runnable_avg_period of 47%
B is on_rq  20/40 ms = 50% of the time which gives a
runnable_avg_sum/runnable_avg_period of 60%
and CPU has a task on its rq 20/40ms = 50% of the time which gives a
runnable_avg_sum/runnable_avg_period of 60%

Yes, that seems about right.