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Date: Tue, 26 Aug 2008 13:55:31 -0400
From: Theodore Tso <tytso@mit.edu>
To: Stefani Seibold <stefani@seibold.net>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
       Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>, linux-kernel@vger.kernel.org,
       Dario Faggioli <raistlin@linux.it>, Max Krasnyansky <maxk@qualcomm.com>,
       Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 6/6] sched: disabled rt-bandwidth by default
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On Tue, Aug 26, 2008 at 03:31:27PM +0200, Stefani Seibold wrote:
> 
> Sorry, the world of embedded programming is sometime stranger than in
> theory. Normally it would not happen that a real-time process locks the
> CPU for more than 1 sec. But in some circumstances, especially FPGA
> initialisation and long term measurements it is possible that the
> real-time process locks the cpu for more than a, sometime for more than
> 10 sec. If the embedded program has designed it in that way, this
> behaviour is desired.
> 

And if that's true, the embedded program can adjust the ulimit to
change the priority levels as appropriately.  Real-time programming
will always required a bit more configuration, such as what priority
various hard and soft interrupt routines will run it.  This is just
one more configuration option. 

> What coming at next? A device driver manager, which kills any driver
> which use to much CPU resource? Or throttle/kicks off the responsible
> driver if the hardware generates to many interrupts?

Actually, we have both of these already.  :-)

						- Ted
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