Re: [v7 0/8] Reduce cross CPU IPI interference

[Gilad Ben-Yossef]

On Thu, Jan 26, 2012 at 5:19 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
>
> On Thu, 2012-01-26 at 12:01 +0200, Gilad Ben-Yossef wrote:
> > Gilad Ben-Yossef (8):
> >   smp: introduce a generic on_each_cpu_mask function
> >   arm: move arm over to generic on_each_cpu_mask
> >   tile: move tile to use generic on_each_cpu_mask
> >   smp: add func to IPI cpus based on parameter func
> >   slub: only IPI CPUs that have per cpu obj to flush
> >   fs: only send IPI to invalidate LRU BH when needed
> >   mm: only IPI CPUs to drain local pages if they exist
>
> These patches look very nice!
>
> Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>

Thank you :-)

If this is of interest, I keep a list tracking global IPI and global
task schedulers sources in the core kernel here:
https://github.com/gby/linux/wiki.

I plan to visit all these potential interference source to see if
something can be done to lower their effect on
isolated CPUs over time.

>
> >   mm: add vmstat counters for tracking PCP drains
> >
> I understood from previous postings this patch wasn't meant for
> inclusion, if it is, note that cpumask_weight() is a potentially very
> expensive operation.

Right. The only purpose of the patch is to show the usefulness
of the previous patch in the series. It is not meant for mainline.

Thanks,
Gilad



--
Gilad Ben-Yossef
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gilad@xxxxxxxxxxxxx
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"Unfortunately, cache misses are an equal opportunity pain provider."
-- Mike Galbraith, LKML
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