From: Sam Bradshaw Date: Fri, 9 May 2014 20:27:07 +0000 (-0700) Subject: NVMe: Adhere to request queue block accounting enable/disable X-Git-Tag: omap-for-v3.16/fixes-against-rc1~12^2~6 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b4e75cbf1364c4bbce3599c3279892a55b6ede07;p=pandora-kernel.git NVMe: Adhere to request queue block accounting enable/disable Recently, a new sysfs control "iostats" was added to selectively enable or disable io statistics collection for request queues. This patch hooks that control. IO statistics collection is rather expensive on large, multi-node machines with drives pushing millions of iops. Having the ability to disable collection if not needed can improve throughput significantly. As a data point, on a quad E5-4640, I see more than 50% throughput improvement when io statistics accounting is disabled during heavily multi-threaded small block random read benchmarks where device performance is in the million iops+ range. Signed-off-by: Sam Bradshaw Signed-off-by: Matthew Wilcox --- Reading git-diff-tree failed