From 7c2c57c9a98bf5961e438a376486f95346f6b0c5 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Tue, 3 Jul 2012 12:12:26 +1000 Subject: [PATCH] md:Add blk_plug in sync_thread. Add blk_plug in sync_thread will increase the performance of sync. Because sync_thread did not blk_plug,so when raid sync, the bio merge not well. Testing environment: SATA controller: Intel Corporation 82801JI (ICH10 Family) SATA AHCI Controller. OS:Linux xxx 3.5.0-rc2+ #340 SMP Tue Jun 12 09:00:25 CST 2012 x86_64 x86_64 x86_64 GNU/Linux. RAID5: four ST31000524NS disk. Without blk_plug:recovery speed about 63M/Sec; Add blk_plug:recovery speed about 120M/Sec. Using blktrace: blktrace -d /dev/sdb -w 60 -o -|blkparse -i - without blk_plug: Total (8,16): Reads Queued: 309811, 1239MiB Writes Queued: 0, 0KiB Read Dispatches: 283583, 1189MiB Write Dispatches: 0, 0KiB Reads Requeued: 0 Writes Requeued: 0 Reads Completed: 273351, 1149MiB Writes Completed: 0, 0KiB Read Merges: 23533, 94132KiB Write Merges: 0, 0KiB IO unplugs: 0 Timer unplugs: 0 add blk_plug: Total (8,16): Reads Queued: 428697, 1714MiB Writes Queued: 0, 0KiB Read Dispatches: 3954, 1714MiB Write Dispatches: 0, 0KiB Reads Requeued: 0 Writes Requeued: 0 Reads Completed: 3956, 1715MiB Writes Completed: 0, 0KiB Read Merges: 424743, 1698MiB Write Merges: 0, 0KiB IO unplugs: 0 Timer unplugs: 3384 The ratio of merge will be markedly increased. Signed-off-by: majianpeng Signed-off-by: NeilBrown --- drivers/md/md.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 1c2f904..973aa84 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -7298,6 +7298,7 @@ void md_do_sync(struct mddev *mddev) int skipped = 0; struct md_rdev *rdev; char *desc; + struct blk_plug plug; /* just incase thread restarts... */ if (test_bit(MD_RECOVERY_DONE, &mddev->recovery)) @@ -7447,6 +7448,7 @@ void md_do_sync(struct mddev *mddev) } mddev->curr_resync_completed = j; + blk_start_plug(&plug); while (j < max_sectors) { sector_t sectors; @@ -7552,6 +7554,7 @@ void md_do_sync(struct mddev *mddev) * this also signals 'finished resyncing' to md_stop */ out: + blk_finish_plug(&plug); wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active)); /* tell personality that we are finished */ -- 2.7.4