lkml.org 
[lkml]   [2002]   [Mar]   [19]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateTue, 19 Mar 2002 14:11:55 +0100 (MET)
From"Maciej W. Rozycki" <>
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        +
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 12:21    [from the cache]
©2003-2008