From 1cf6aa74b32f18f9b5faf525a93b0c1f609acb1f Mon Sep 17 00:00:00 2001 From: Lidong Chen Date: Wed, 15 Mar 2017 11:37:33 +0800 Subject: [PATCH] migration/block: Avoid invoking blk_drain too frequently Increase bmds->cur_dirty after submit io, so reduce the frequency involve into blk_drain, and improve the performance obviously when block migration. The performance test result of this patch: During the block dirty save phase, this patch improve guest os IOPS from 4.0K to 9.5K. and improve the migration speed from 505856 rsec/s to 855756 rsec/s. Signed-off-by: Lidong Chen Reviewed-by: Fam Zheng Signed-off-by: Juan Quintela --- migration/block.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/migration/block.c b/migration/block.c index 6741228200..7734ff728a 100644 --- a/migration/block.c +++ b/migration/block.c @@ -576,6 +576,9 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds, } bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, sector, nr_sectors); + sector += nr_sectors; + bmds->cur_dirty = sector; + break; } sector += BDRV_SECTORS_PER_DIRTY_CHUNK; -- 2.11.4.GIT