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Subject: Re: Preemption question (4xx related)
From: Michel =?ISO-8859-1?Q?D=E4nzer?= <michel@daenzer.net>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Date: Thu, 02 Jul 2009 11:14:29 +0200
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Cc: linuxppc-dev@ozlabs.org, Felix Radensky <felix@embedded-sol.com>
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On Thu, 2009-07-02 at 08:13 +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2009-06-30 at 05:55 -0700, Felix Radensky wrote:
> > Hi,
> >=20
> > Preemption is disabled on the vast majority of powerpc
> > targets. Are there any known problems in this area ?
> > I'd like to enable CONFIG_PREEMPT_VOLUNTARY on
> > AMCC 405EX target, to increase application responsiveness.
> > Is it a bad idea ?
>=20
> In theory it should work, but as you may have noticed, it's generally
> disabled and thus not very well tested.
>=20
> It would be a good idea for us, some of the core devs, to turn that on
> in our usual test configs in fact.

FWIW, on my PowerBook I've been running with CONFIG_PREEMPT_VOLUNTARY
enabled for a long time (more than a year). No problems so far, and it
definitely seems to help a lot for interactivity.


--=20
Earthling Michel D=C3=A4nzer           |                http://www.vmware.c=
om
Libre software enthusiast         |          Debian, X and DRI developer