Messages in this thread | | | Date | Mon, 27 Jun 2005 07:08:26 -0700 | From | "Martin J. Bligh" <> | Subject | Re: [rfc] lockless pagecache |
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--Andrew Morton <akpm@osdl.org> wrote (on Monday, June 27, 2005 00:46:24 -0700):
> Nick Piggin <nickpiggin@yahoo.com.au> wrote: >> >> First I'll put up some numbers to get you interested - of a 64-way Altix >> with 64 processes each read-faulting in their own 512MB part of a 32GB >> file that is preloaded in pagecache (with the proper NUMA memory >> allocation). > > I bet you can get a 5x to 10x reduction in ->tree_lock traffic by doing > 16-page faultahead.
Maybe true, but when we last tried that, faultahead sucked for performance in a more general sense. All the extra setup and teardown cost for unnecessary PTEs kills you, even if it's only 4 pages or so.
M.
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