From 6e24dffcbacea0c2537ffad3f165fa06d14ddc10 Mon Sep 17 00:00:00 2001 From: Dave Kleikamp Date: Thu, 15 Dec 2011 22:44:45 +0100 Subject: AIO: Don't plug the I/O queue in do_io_submit() Asynchronous I/O latency to a solid-state disk greatly increased between the 2.6.32 and 3.0 kernels. By removing the plug from do_io_submit(), we observed a 34% improvement in the I/O latency. Unfortunately, at this level, we don't know if the request is to a rotating disk or not. Change-Id: I7101df956473ed9fd5dcff18e473dd93b688a5c1 Signed-off-by: Dave Kleikamp Cc: linux-aio@kvack.org Cc: Chris Mason Cc: Jens Axboe Cc: Andi Kleen Cc: Jeff Moyer --- fs/aio.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 02a0f6be2..ebca5ab5f 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1165,7 +1165,6 @@ long do_io_submit(aio_context_t ctx_id, long nr, struct kioctx *ctx; long ret = 0; int i = 0; - struct blk_plug plug; if (unlikely(nr < 0)) return -EINVAL; @@ -1182,8 +1181,6 @@ long do_io_submit(aio_context_t ctx_id, long nr, return -EINVAL; } - blk_start_plug(&plug); - /* * AKPM: should this return a partial result if some of the IOs were * successfully submitted? @@ -1206,8 +1203,6 @@ long do_io_submit(aio_context_t ctx_id, long nr, if (ret) break; } - blk_finish_plug(&plug); - put_ioctx(ctx); return i ? i : ret; } -- cgit v1.2.3