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 <jemmy858585@gmail.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
master
Lidong Chen 2017-03-15 11:37:33 +08:00 committed by Juan Quintela
parent 4af245dc3e
commit 1cf6aa74b3
1 changed files with 3 additions and 0 deletions

View File

@ -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;