Re: Q: explicit alignment control for the slab allocator

Manfred Spraul (manfred@colorfullife.com)
Thu, 01 Mar 2001 20:47:12 +0100


"David S. Miller" wrote:
>
> Manfred, why are you changing the cache alignment to
> SMP_CACHE_BYTES? If you read the original SLAB papers
> and other documents, the code intends to color the L1
> cache not the L2 or subsidiary caches.
>
I'll undo that change.

I only found this comment in the source file:

> /* For performance, all the general caches are L1 aligned.
> * This should be particularly beneficial on SMP boxes, as it
> * eliminates "false sharing".
> * Note for systems short on memory removing the alignment will
> * allow tighter packing of the smaller caches. */

To avoid false sharing we would need SMP_CACHE_BYTES aligning, not L1
aligning.

--
	Manfred
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