Re: [PATCH] 2.4.18 scheduler bugs

From: Ingo Molnar (
Date: Fri Mar 15 2002 - 15:35:49 EST

On Fri, 15 Mar 2002, Joe Korty wrote:

> >> Idle tasks nowdays don't spin waiting for need->resched to change,
> >> they sleep on a halt insn instead. Therefore any setting of
> >> need->resched on an idle task running on a remote CPU should be
> >> accompanied by a cross-processor interrupt.
> >
> > this is broken as well. Check out the idle=poll feature i wrote some time
> > ago.
> The idle=poll stuff is a hack. [...]

it's a feature.

> [...] I'd like my idle cpus to sleep and still have them wake up the
> moment work for them becomes available. I see no reason why an idle cpu
> should be forced to remain idle until the next tick, nor why fixing that
> should be considered `broken'.

performance. IPIs are expensive.


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This archive was generated by hypermail 2b29 : Fri Mar 15 2002 - 22:00:22 EST