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From: NOULARD Eric <enoulard@free.fr>
To: Linux SMP <linux-smp@vger.kernel.org>
Subject: Re: Where to find good doc ?
Date: Thu, 16 Dec 2004 23:14:53 +0100	[thread overview]
Message-ID: <1103235292.4766.76.camel@bagherra.bordeneuve.fr> (raw)
In-Reply-To: <41C09846.5050204@teleauto.org>

Le mer 15/12/2004 à 21:02, Philippe Martinole a écrit : 
> Hello everyone,
> 
> I've been looking for a doc on SMP since a while but I can't find what I want.
> Do you know some good doc to read ?
> To be more precese, I want to put all processes on only one cpu except
> nly one real time process on the second cpu.

What you want to do is Asymetric multiprocessing using SMP
(Symmetric Multi-Processor) so SMP doc won't help you so much :))

You may have a look to this rthowto:
http://people.mech.kuleuven.ac.be/~bruyninc/rthowto/
which contains valuable information RT and linux including
SMP aspects.

Regarding linux SMP handling and [soft] realtime you
must know that each process may have a processor affinity
which may be set with the sched_setaffinity syscall.
(beware of glibc moving interface regarding this syscal)

Then each interrupt has its smp_affinity which may
be set using /proc/irq/<num>/smp_affinity

As you can see there is NO standard SMP linux feature to
isolate/reserve one (or several) CPU from being used by
processes.

This kind of behavior may be obtained using either 
sub-kernel approach (RTLinux or RTAI
http://www.aero.polimi.it/~rtai/) or using proprietary
extension such as CPU shielding
http://www.linuxdevices.com/articles/AT8610061752.html
http://linuxdevices.com/files/article030/shielded-cpu.pdf

Hope this helps.

> Thanks,
> 
> Philippe
> 
> 
> -
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-- 
Eric NOULARD
E-mail: enoulard@free.fr


      reply	other threads:[~2004-12-16 22:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-15 20:02 Where to find good doc ? Philippe Martinole
2004-12-16 22:14 ` NOULARD Eric [this message]

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