From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Thu, 08 Mar 2007 11:08:09 +0100
From: Steven Scholz <steven.scholz@domain.hid>
MIME-Version: 1.0
Subject: Re: [Xenomai-core] xenomai preempting interrupt handler ?
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Philippe,

>> using an oscilloscope I found that the AT91RM9200 spends up to 300=B5s=
 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?
>=20
> Hw interrupts are forcibly enabled before entering any Linux IRQ
> handler, exactely to prevent the issue you described (e.g. fiddling wit=
h
> 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?
>=20
> 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?

Steven