Messages in this thread |  | | | Subject | Re: [PATCH] Radix-tree pagecache for 2.5 | | From | Momchil Velikov <> | | Date | 01 Feb 2002 08:32:40 +0200 |
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>>>>> "Anton" == Anton Blanchard <anton@samba.org> writes:
Anton> Hi Ingo,
>> Yes, it's very nice. Anton Blanchard has benchmarked both patch variants >> (tree vs. scalable-hash page buckets) for SMP scalability against the >> stock hash, on big RAM, many CPUs boxes, via dbench load. He has found >> performance of radix trees vs. scalable hash to be at least equivalent. (i >> think Anton has a few links to show the resulting graphs.)
Anton> Here are some results on a 12 way machine. (2.4.16-splay is the radix Anton> patch):
Anton> http://samba.org/~anton/linux/pagecache_locking/1/summary.png
A correction, "-splay" is the very first variant I posted, which used splay trees for the page cache.
Anton> As you can see both patches give pretty much equal improvements.
Anton> The other problem with the current pagecache hash is that it maxes out Anton> at order 9 (due to the get_free_pages limitation) which starts to hurt Anton> at 4GB RAM and above. On a 32GB machine the average hashchain depth Anton> was very high:
Anton> http://samba.org/~anton/linux/pagecache/pagecache_before.png
Anton> There were a few solutions (from davem and ingo) to allocate a larger Anton> hash but with the radix patch we no longer have to worry about this.
Anton> So the radix patch solves 2 problems quite nicely :)
Anton> Anton - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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