From: Jens Axboe <axboe@suse.de>
Date: Fri, 16 Jun 2006 09:23:00 +0000 (+0200)
Subject: [PATCH] cfq-iosched: many performance fixes
X-Git-Tag: v2.6.18-rc1~1081^2~7
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=caaa5f9f0a75d1dc5e812e69afdbb8720e077fd3;p=pandora-kernel.git

[PATCH] cfq-iosched: many performance fixes

This is a collection of patches that greatly improve CFQ performance
in some circumstances.

- Change the idling logic to only kick in after a request is done and we
  are deciding what to do. Before the idling included the request service
  time, so it was hard to adjust. Now it's true think/idle time.

- Take advantage of TCQ/NCQ/queueing for seeky sync workloads, but keep
  it in control for sync and sequential (or close to) workloads.

- Expire queues immediately and move on to other busy queues, if we are
  not going to idle after the current one finishes.

- Don't rearm idle timer if there are no busy queues. Just leave the
  system idle.

Signed-off-by: Jens Axboe <axboe@suse.de>
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