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| author | Jens Axboe <jens.axboe@oracle.com> | 2007-04-20 08:55:52 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-04-20 22:56:29 -0700 |
| commit | a993800655ee516b6f6a6fc4c2ee13fedfb0590b (patch) | |
| tree | 023b362b4b30bddf2232ade83d162a84ac88f74b /arch/i386/kernel/cpu/cpufreq/longhaul.c | |
| parent | 46fcc86dd71d70211e965102fb69414c90381880 (diff) | |
| download | lwn-a993800655ee516b6f6a6fc4c2ee13fedfb0590b.tar.gz lwn-a993800655ee516b6f6a6fc4c2ee13fedfb0590b.zip | |
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 <valerie.clement@bull.net> 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 <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/i386/kernel/cpu/cpufreq/longhaul.c')
0 files changed, 0 insertions, 0 deletions