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| author | Jeff Moyer <jmoyer@redhat.com> | 2009-10-02 18:57:36 -0400 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-10-28 09:29:25 +0100 |
| commit | cfb1e33eed48165763edc7a4a067cf5f74898d0b (patch) | |
| tree | d0e0bdd0664615b1f7be6cf770476e16dbcad116 /fs/direct-io.c | |
| parent | 1af60fbd759d31f565552fea315c2033947cfbe6 (diff) | |
| download | lwn-cfb1e33eed48165763edc7a4a067cf5f74898d0b.tar.gz lwn-cfb1e33eed48165763edc7a4a067cf5f74898d0b.zip | |
aio: implement request batching
Hi,
Some workloads issue batches of small I/O, and the performance is poor
due to the call to blk_run_address_space for every single iocb. Nathan
Roberts pointed this out, and suggested that by deferring this call
until all I/Os in the iocb array are submitted to the block layer, we
can realize some impressive performance gains (up to 30% for sequential
4k reads in batches of 16).
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'fs/direct-io.c')
| -rw-r--r-- | fs/direct-io.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/direct-io.c b/fs/direct-io.c index c86d35f142de..3af761c8c5cc 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1028,9 +1028,6 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, if (dio->bio) dio_bio_submit(dio); - /* All IO is now issued, send it on its way */ - blk_run_address_space(inode->i_mapping); - /* * It is possible that, we return short IO due to end of file. * In that case, we need to release all the pages we got hold on. @@ -1057,8 +1054,11 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode, ((rw & READ) || (dio->result == dio->size))) ret = -EIOCBQUEUED; - if (ret != -EIOCBQUEUED) + if (ret != -EIOCBQUEUED) { + /* All IO is now issued, send it on its way */ + blk_run_address_space(inode->i_mapping); dio_await_completion(dio); + } /* * Sync will always be dropping the final ref and completing the |