On Wed, 13 Mar 2002, Ingo Molnar wrote:
>
> On Wed, 13 Mar 2002, Martin Wilck wrote:
>
> > First of all, we see that virtually 100% of all IRQs are handled by
> > CPU 0. I have seen this reported a number of times before. I guess it
> > can become a severe performance problem in IRQ-intensive situations.
>
> i've written a patch for this, it's enclosed in this email. It implements
> a brownean motion of IRQs, based on load patterns. The concept works
> really well on Foster CPUs - eg. it will redirect IRQs to idle CPUs - but
> if all CPUs are idle then the IRQs are randomly and evenly distributed
> between CPUs.
>
> (the patch can be made cheaper, but i've kept the overhead per-IRQ for the
> time being to have more flexibility.)
>
> let me know whether this fixes your problem,
>
Hi Ingo,
I've tested your patch with a 2.4.18 kernel on a few SMP systems : i860,
Plumas (E7500), 760MP(X), ServerWorks HE-SL and ServerWorks LE. It works
fine in all cases. I had to modify the patch a little bit in order to make
it compile on uniprocessor. I've attached the modified patch.
Will this patch be included in 2.4.19 ?
Regards,
--
Steffen Persvold | Scalable Linux Systems | Try out the world's best
mailto:sp@scali.com | http://www.scali.com | performing MPI implementation:
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