Messages in this thread | | | Date | Wed, 7 Mar 2018 13:24:37 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v5 1/4] sched/fair: add util_est on top of PELT |
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On Wed, Mar 07, 2018 at 11:31:49AM +0000, Patrick Bellasi wrote: > > It appears to me this isn't a stable situation and completely relies on > > the !nr_running case to recalibrate. If we ensure that doesn't happen > > for a significant while the sum can run-away, right? > > By away you mean go over 1024 or overflow the unsigned int storage?
the later, I think you can make it arbitrarily large. Have a busy task on CPU0, this ensure !nr_running never happens.
Start a busy task on CPU1, wait for it to hit u=1, then migrate it to CPU0, then wait for it to hit u=.5 then kill it, this effectively adds .5 to the enqueued value, repeat indefinitely.
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