From: Philippe Gerum <rpm@xenomai.org>
To: Steven Scholz <steven.scholz@domain.hid>
Cc: Xenomai-core@domain.hid
Subject: Re: [Xenomai-core] xenomai preempting interrupt handler ?
Date: Thu, 08 Mar 2007 11:19:17 +0100 [thread overview]
Message-ID: <1173349157.17515.19.camel@domain.hid> (raw)
In-Reply-To: <45EFE089.9000508@domain.hid>
On Thu, 2007-03-08 at 11:08 +0100, Steven Scholz wrote:
> Philippe,
>
> >> using an oscilloscope I found that the AT91RM9200 spends up to 300µs in the
> >> interrupt handler for ethernet controller.
> >>
> >> Now I wonder if this interrupt handler will be preempted by Xenomai if there
> >> is a high priority, periodic real time task?
> >
> > Hw interrupts are forcibly enabled before entering any Linux IRQ
> > handler, exactely to prevent the issue you described (e.g. fiddling with
> > an IDE controller in PIO mode also gives funky latency results unless
> > the latter is true), so the answer is yes.
> Thanks.
>
> >> Thus will the duration of the
> >> ethernet interrupt handler add the the worst case latency?
> >
> > Not from Linux IRQ handlers; you may want to check this using the
> > tracer. If hw interrupts are masked there, then it's a blatant bug.
>
> How could I check this using the tracer? Small hint please?
http://www.xenomai.org/index.php/I-pipe:Tracer
>
> Steven
--
Philippe.
next prev parent reply other threads:[~2007-03-08 10:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-08 9:29 [Xenomai-core] xenomai preempting interrupt handler ? Steven Scholz
2007-03-08 9:42 ` Philippe Gerum
2007-03-08 10:08 ` Steven Scholz
2007-03-08 10:19 ` Philippe Gerum [this message]
2007-03-08 10:20 ` Steven Scholz
2007-03-08 10:28 ` Philippe Gerum
2007-03-08 11:49 ` Steven Scholz
2007-03-08 12:22 ` Philippe Gerum
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