Are hardware interrupts programmed to be delivered in round robin fashion in
Xen? If yes then interrupt from a particular device can go to different
processor.
-----Original Message-----
From: Daniel Stodden [mailto:stodden@cs.tum.edu]
Sent: Tuesday, October 23, 2007 7:02 PM
To: Agarwal, Lomesh
Cc: Xen Developers
Subject: Re: [Xen-devel] hardware interrupt
On Tue, 2007-10-23 at 15:57 -0700, Agarwal, Lomesh
wrote:> Is there a way I can find out on which physical processor I am receiving
> interrupt from a particular device?
if you know the irq number.
the path taken on irqs is roughly IRQ0x**_interrupt -> common_interrupt
-> do_IRQ() (C, finally), then back to guest context via ret_from_intr.
see the definition of BUILD_COMMON_INTERRUPT() and related.
if it''s bound, it will visit send_guest_pirq().
as far as i know, the physical cpu does not leak to guest context, so
it''s going to be the VMM.
you get the physical cpu number via smp_processor_id().
> Can I put prints somewhere in Xen to
> do that?
printk in irq context isn''t exactly scalable, but you''ll might
just get
away with it.
hth,
daniel
--
Daniel Stodden
LRR - Lehrstuhl für Rechnertechnik und Rechnerorganisation
Institut für Informatik der TU München D-85748 Garching
http://www.lrr.in.tum.de/~stodden mailto:stodden@cs.tum.edu
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