Re: SCHED_IDLE documentation

From: Ingo Molnar
Date: Mon Mar 03 2008 - 07:53:06 EST



* Michael Kerrisk <mtk.manpages@xxxxxxxxxxxxxx> wrote:

> > > * What's the difference between SCHED_IDLE and SCHED_BATCH?
> >
> > SCHED_BATCH can still have nice levels from -20 to +19, it is a
> > modified SCHED_OTHER/SCHED_NORMAL for "throughput oriented"
> > workloads.
>
> So, suppose we have two CPU intensive jobs, one SCHED_OTHER and the
> other SCHED_BATCH. If they have the same nice value, will/should the
> scheduler favour one over the other?

yes - SCHED_BATCH does not modify the CPU usage proportion for
CPU-intense tasks, it's their nice value that controls the proportion.
What it will influence is wakeup behavior - i.e. wakeup-intense
workloads should schedule less with SCHED_BATCH. (but how that is done
is really fluid and will probably tweaked in the future.)

Ingo
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