From: Alan D. Brunelle Date: Fri, 29 Jan 2010 08:04:08 +0000 (+0100) Subject: block: Added in stricter no merge semantics for block I/O X-Git-Tag: v2.6.34-rc1~242^2~29 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=488991e28e55b4fbca8067edf0259f69d1a6f92c;p=pandora-kernel.git block: Added in stricter no merge semantics for block I/O Updated 'nomerges' tunable to accept a value of '2' - indicating that _no_ merges at all are to be attempted (not even the simple one-hit cache). The following table illustrates the additional benefit - 5 minute runs of a random I/O load were applied to a dozen devices on a 16-way x86_64 system. nomerges Throughput %System Improvement (tput / %sys) -------- ------------ ----------- ------------------------- 0 12.45 MB/sec 0.669365609 1 12.50 MB/sec 0.641519199 0.40% / 2.71% 2 12.52 MB/sec 0.639849750 0.56% / 2.96% Signed-off-by: Alan D. Brunelle Signed-off-by: Jens Axboe --- Reading git-diff-tree failed