Re: [PATCH sched-devel 0/7] CPU isolation extensions

From: Peter Zijlstra
Date: Fri Feb 22 2008 - 09:00:24 EST



On Fri, 2008-02-22 at 08:38 -0500, Mark Hounschell wrote:

> >> List of commits
> >> cpuisol: Make cpu isolation configrable and export isolated map
> >
> > cpu_isolated_map was a bad hack when it was introduced, I feel we should
> > deprecate it and fully integrate the functionality into cpusets. That would
> > give a much more flexible end-result.
> >
> > CPU-sets can already isolate cpus by either creating a cpu outside of any set,
> > or a set with a single cpu not shared by any other sets.
> >
>
> Peter, what about when I am NOT using cpusets and are disabled in my config but
> I still want to use this?

Then you enable it?

> >> cpuisol: Do not schedule workqueues on the isolated CPUs
> >
> > (per-cpu workqueues, the single ones are treated in the previous section)
> >
> > I still strongly disagree with this approach. Workqueues are passive, they
> > don't do anything unless work is provided to them. By blindly not starting them
> > you handicap the system and services that rely on them.
> >
>
> Have things changed since since my first bad encounter with Workqueues.
> I am referring to this thread.
>
> http://kerneltrap.org/mailarchive/linux-kernel/2007/5/29/97039

Just means you get to fix those problems. By blindly not starting them
you introduce others.

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