Re: [rfc] lockless pagecache

--Andrew Morton [off-list ref] wrote (on Monday, June 27, 2005 00:46:24 -0700):

Nick Piggin [off-list ref] wrote:

quoted

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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