lkml.org 
[lkml]   [2002]   [Jan]   [5]   [last100]   RSS Feed
Views: [more markup]   [less markup]   [headers]   [forward]  
 
Messages in this thread
/
SubjectRe: [announce] [patch] ultra-scalable O(1) SMP and UP scheduler
DateSat, 5 Jan 2002 23:41:38 +0000 (GMT)
FromAlan Cox <>
> > In fact it's the cr3 switch (movl %0, %%cr3) that accounts for about 30%
> > of the context switch cost. On x86. On other architectures it's often
> > much, much cheaper.
> 
> TLB flushes are expensive everywhere, and you know exactly this and if you

Not every processor is dumb enough to have TLB flush on a context switch.
If you have tags on your tlb/caches it's not a problem.

> Again, the history of our UP scheduler thought us that noone has been able
> to makes it suffer with realistic/high not-stupid-benchamrks loads.

Apache under load, DB2, Postgresql, Lotus domino all show bad behaviour. 
(Whether apache, db2, and postgresql want fixing differently is a seperate
 argument)

Alan
-
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 12:15    [from the cache]
©2003-2008