Re: interactive task starvation

Ingo Molnar
2006-03-21T14:32:52Z

* Con Kolivas <kernel@kolivas.org> wrote:

> On Wednesday 22 March 2006 01:25, Ingo Molnar wrote:
> > * Con Kolivas <kernel@kolivas.org> wrote:
> > > 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.
>
> With nothing else running on the machine it should still get all the
> cpu no matter which array it's on though.

yes. I thought you were asking why 'ls' pauses so long during the
aforementioned workloads (of loadavg 7-8) - and i answered that. If you
meant something else then please re-explain it to me.

Ingo