Re: [Xen-ia64-devel] iosapic virtualisation

[Alex Williamson <alex.williamson@xxxxxx>]

On Wed, 2006-02-01 at 12:35 +0100, Tristan Gingold wrote:
> Le Mercredi 01 Février 2006 10:11, Tristan Gingold a écrit :
> > Le Mardi 31 Janvier 2006 20:53, Alex Williamson a écrit :
> > > On Tue, 2006-01-31 at 12:29 +0100, Tristan Gingold wrote:
> [...]
> > >       * The vector-to-rte lookup in xen_reflect_interrupt_to_domain()
> > >         looks rather heavy weight.  It seems like we should be able to
> > >         construct the data structures for a direct look up here.  I
> > >         don't think we can afford to scan the rte list for every
> > >         interrupt.
> Oups, forget my previous answer.
> It is not heavy weight, but rather directly indexed.  There should be one RTE 
> per vector.

   Ok, so it should be a fast lookup.  Good.

> However, the RTE lookup in iosapic_guest_write is heavy-weight.
> I will check wether it is often used or not.

   EOIs could happen quite often, so it might be best to optimize it.
Have you done any quick dom0 performance testing to see how much
overhead this adds?  Thanks,

        Alex

-- 
Alex Williamson                             HP Linux & Open Source Lab


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