From: Jens Axboe Date: Fri, 20 Apr 2007 06:55:52 +0000 (+0200) Subject: cfq-iosched: fix sequential write regression X-Git-Tag: v2.6.21~44 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a993800655ee516b6f6a6fc4c2ee13fedfb0590b;p=pandora-kernel.git cfq-iosched: fix sequential write regression We have a 10-15% performance regression for sequential writes on TCQ/NCQ enabled drives in 2.6.21-rcX after the CFQ update went in. It has been reported by Valerie Clement and the Intel testing folks. The regression is because of CFQ's now more aggressive queue control, limiting the depth available to the device. This patches fixes that regression by allowing a greater depth when only one queue is busy. It has been tested to not impact sync-vs-async workloads too much - we still do a lot better than 2.6.20. Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed