Messages in this thread | | | Date | Tue, 21 Mar 2006 15:25:04 +0100 | From | Ingo Molnar <> | Subject | Re: interactive task starvation |
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* Con Kolivas <kernel@kolivas.org> wrote:
> On Wednesday 22 March 2006 01:17, Mike Galbraith wrote: > > On Wed, 2006-03-22 at 00:53 +1100, Con Kolivas wrote: > > > The yardstick for changes is now the speed of 'ls' scrolling in the > > > console. Where exactly are those extra cycles going I wonder? Do you > > > think the scheduler somehow makes the cpu idle doing nothing in that > > > timespace? Clearly that's not true, and userspace is making something > > > spin unnecessarily, but we're gonna fix that by modifying the > > > scheduler.... sigh > > > > *Blink* > > > > Are you having a bad hair day?? > > My hair is approximately 3mm long so it's kinda hard for that to happen. > > What you're fixing with unfairness is worth pursuing. The 'ls' issue > just blows my mind though for reasons I've just said. Where are the > magic cycles going when nothing else is running that make it take ten > times longer?
i believe such artifacts are due to array switches not happening (due to the workload getting queued back to rq->active, not rq->expired), and 'ls' only gets a timeslice once in a while, every STARVATION_LIMIT times. I.e. such workloads penalize the CPU-bound 'ls' process quite heavily.
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