From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46506) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cnzl4-0007Gi-S2 for qemu-devel@nongnu.org; Tue, 14 Mar 2017 23:37:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cnzl1-0007Uj-Qw for qemu-devel@nongnu.org; Tue, 14 Mar 2017 23:37:54 -0400 From: Lidong Chen Date: Wed, 15 Mar 2017 11:37:33 +0800 Message-Id: <1489549053-31728-1-git-send-email-jemmy858585@gmail.com> Subject: [Qemu-devel] [PATCH v2] migration/block: Avoid invoking blk_drain too frequently List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: stefanha@redhat.com, famz@redhat.com, quintela@redhat.com, dgilbert@redhat.com, qemu-block@nongnu.org, Lidong Chen 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 --- migration/block.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/migration/block.c b/migration/block.c index 6741228..7734ff7 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; -- 1.8.3.1