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Date: Mon, 11 Feb 2008 22:30:16 +0100
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From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Subject: Re: [Xenomai-core] [Xenomai-help] AT91SAM9260 latency
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To: Jan Kiszka <jan.kiszka@domain.hid>
Cc: jagarcia@domain.hid, xenomai@xenomai.org

Jan Kiszka wrote:
 > There is a shadow relax procedure running before the timer IRQ fires,
 > and that takes another context switch. So the latency sum is:
 > 
 >  - unrelated context switch
 >  - timer IRQ
 >  - switch to woken up RT process
 >  - serial IRQ
 > 
 > Almost the theoretical worst case.

The problem is that it does not happen when launching latency with -t 1
or -t 2, or if latency is not run in the background.

Anyway, I will investigate on the double ack issue, because it could
mean that there is a double EOI, which, I guess could cause some
troubles at interrupt controller level.

-- 


					    Gilles Chanteperdrix.