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Date: Mon, 24 Jan 2005 21:55:09 +0100
From: Ingo Molnar <mingo@elte.hu>
To: "Jack O'Quin" <joq@io.com>
Cc: Con Kolivas <kernel@kolivas.org>, Paul Davis <paul@linuxaudiosystems.com>,
       linux <linux-kernel@vger.kernel.org>, rlrevell@joe-job.com,
       CK Kernel <ck@vds.kolivas.org>, utz <utz@s2y4n2c.de>,
       Andrew Morton <akpm@osdl.org>, alexn@dsv.su.se,
       Rui Nuno Capela <rncbc@rncbc.org>
Subject: Re: [PATCH]sched: Isochronous class v2 for unprivileged soft rt scheduling
Message-ID: <20050124205509.GB20485@elte.hu>
References: <200501201542.j0KFgOwo019109@localhost.localdomain> <87y8eo9hed.fsf@sulphur.joq.us> <20050120172506.GA20295@elte.hu> <877jm3qqxz.fsf@sulphur.joq.us>
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* Jack O'Quin <joq@io.com> wrote:

> Has anyone done this kind of realtime testing on an SMP system?  I'd
> love to know how they compare.  Unfortunately, I don't have access to
> one at the moment.  Are they generally better or worse for this kind
> of work?  I'm not asking about partitioning or processor affinity, but
> actually using the entire SMP complex as a realtime machine.

this particular test was done with an UP kernel. (although the
testsystem indeed is an SMP box.) Generally i mention SMP explicitly. 
There are a couple of patches in the -RT tree to make RT scheduling
better on SMP systems.

with those fixes applied (i.e. under the -RT kernel), jackd/jack_test
behaves better than on a single CPU. I didnt find any scheduling anomaly
that wasnt caused by the kernel.

	Ingo