tree f3aebe4f1ee8138db560b049f84d30a4b7348e8a
parent 9a8c28c8311e30ba97499447d5a11662f5aea094
author Shaohua Li <shaohua.li@intel.com> 1267431654 +0100
committer Jens Axboe <jens.axboe@oracle.com> 1267431654 +0100

cfq-iosched: quantum check tweak

Currently a queue can only dispatch up to 4 requests if there are other queues.
This isn't optimal, device can handle more requests, for example, AHCI can
handle 31 requests. I can understand the limit is for fairness, but we could
do a tweak: if the queue still has a lot of slice left, sounds we could
ignore the limit. Test shows this boost my workload (two thread randread of
a SSD) from 78m/s to 100m/s.
Thanks for suggestions from Corrado and Vivek for the patch.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>