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SubjectRe: [this_cpu_xx V6 7/7] this_cpu: slub aggressive use of this_cpu operations in the hotpaths
On Fri, 16 Oct 2009, Christoph Lameter wrote:

> > TCP_STREAM stresses a few specific caches:
> >
> > ALLOC_FASTPATH ALLOC_SLOWPATH FREE_FASTPATH FREE_SLOWPATH
> > kmalloc-256 3868530 3450592 95628 7223491
> > kmalloc-1024 2440434 429 2430825 10034
> > kmalloc-4096 3860625 1036723 85571 4811779
> >
> > This demonstrates that freeing to full (or partial) slabs causes a lot of
> > pain since the fastpath normally can't be utilized and that's probably
> > beyond the scope of this patchset.
> >
> > It's also different from the cpu slab thrashing issue I identified with
> > the TCP_RR benchmark and had a patchset to somewhat improve. The
> > criticism was the addition of an increment to a fastpath counter in struct
> > kmem_cache_cpu which could probably now be much cheaper with these
> > optimizations.
>
> Can you redo the patch?
>

Sure, but it would be even more inexpensive if we can figure out why the
irqless patch is hanging my netserver machine within the first 60 seconds
on the TCP_RR benchmark. I guess nobody else has reproduced that yet.


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