Re: [this_cpu_xx V6 7/7] this_cpu: slub aggressive use of this_cpuoperations in the hotpaths

From: Christoph Lameter
Date: Fri Oct 16 2009 - 12:53:21 EST


On Thu, 15 Oct 2009, David Rientjes 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?

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