Re: must-fix list, v5

From: Andrew Theurer (habanero@us.ibm.com)
Date: Wed May 21 2003 - 20:25:47 EST


On Wednesday 21 May 2003 17:22, Andrew Morton wrote:
> +o Overeager affinity in presence of repeated yields
> +
> + http://www.hpl.hp.com/research/linux/kernel/o1-openmp.php
> +
> + ingo: this is valid. fix is in progress.

I have seen this with SpecJBB on high warehouse runs in around 2.5.66, I am
testing now to see if it still exists in 2.5.69. In 2.5.66 adding a bit to
try_to_wakeup to relocate p-task_cpu to an idle cpu (if available) if the
p->task_cpu is currently non idle helped dramatically. This change is also
in Andrea's 2.4 kernel tree I believe. Basically in some situations, a quick
push load balance before task activation.

Also, in this particular case, this behavior may go away with the use of
futexes in JVM, not sure yet, so I don't know if JVM and JBB are good
justifications to make this change.

-Andrew Theurer

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