Re: [patch] sched: fix scheduling latencies for !PREEMPT kernels

From: Ingo Molnar
Date: Tue Sep 14 2004 - 10:06:25 EST



* Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:

> Another thing, I don't mean this to sound like a rhetorical question,
> but if we have a preemptible kernel, why is it a good idea to sprinkle
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> cond_rescheds everywhere? Isn't this now the worst of both worlds? Why
> would someone who really cares about latency not enable preempt?

two things:

1) none of the big distros enables CONFIG_PREEMPT in their kernels - not
even SuSE. This is pretty telling.

2) 10 new cond_resched()'s are not precisely 'sprinkle everywhere'.

Ingo
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