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SubjectRe: Severe IRQ problems on Foster (P4 Xeon) system
On Wed, 13 Mar 2002, Ingo Molnar wrote:

> 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.

A nice idea. One note though -- the code depends on the TSC to be
present. It would be better to use:

if (cpu_has_tsc)
rdtscll(random_number);

and either preset random_number to a fixed value or even leave it
uninitialized to have it somewhat randomly set by what was found at the
stack for the TSC-less case.

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +

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