cfq: improve fsync performance for small files
Fsync performance for small files achieved by cfq on high-end disks is lower than what deadline can achieve, due to idling introduced between the sync write happening in process context and the journal commit. Moreover, when competing with a sequential reader, a process writing small files and fsync-ing them is starved. This patch fixes the two problems by: - marking journal commits as WRITE_SYNC, so that they get the REQ_NOIDLE flag set, - force all queues that have REQ_NOIDLE requests to be put in the noidle tree. Having the queue associated to the fsync-ing process and the one associated to journal commits in the noidle tree allows: - switching between them without idling, - fairness vs. competing idling queues, since they will be serviced only after the noidle tree expires its slice. Acked-by: NVivek Goyal <vgoyal@redhat.com> Reviewed-by: NJeff Moyer <jmoyer@redhat.com> Tested-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NCorrado Zoccolo <czoccolo@gmail.com> Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
Showing
想要评论请 注册 或 登录