tree 07aba6bac5a57cb3efd23762acfd719e255775ab
parent 35e6077cb16f93517ba5a51ba849b186d2474d60
author Jens Axboe <axboe@suse.de> 1150449780 +0200
committer Jens Axboe <axboe@nelson.home.kernel.dk> 1151075439 +0200

[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>