diff options
author | Denis V. Lunev <den@openvz.org> | 2015-04-28 10:46:57 +0300 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2015-05-22 09:37:32 +0100 |
commit | 0d31c7c200b3dca2aeeaa6f74ff3fd539aad803a (patch) | |
tree | e8b2a49fe7133c5c81387cbcc1406518789e6b2a /linux-user/cris | |
parent | 2d68e22e94e8bc5a0d32a38b53c592c320db8261 (diff) |
block/parallels: delay writing to BAT till bdrv_co_flush_to_os
The idea is that we do not need to immediately sync BAT to the image as
from the guest point of view there is a possibility that IO is lost
even in the physical controller until flush command was finished.
bdrv_co_flush_to_os is exactly the right place for this purpose.
Technically the patch uses loaded BAT data as a cache and performs
actual on-disk metadata updates in parallels_co_flush_to_os callback.
This patch speed ups
qemu-img create -f parallels -o cluster_size=64k ./1.hds 64G
qemu-io -f parallels -c "write -P 0x11 0 1024k" 1.hds
writing from 50-60 Mb/sec to 80-90 Mb/sec on rotational media and
from 160 Mb/sec to 190 Mb/sec on SSD disk.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Roman Kagan <rkagan@parallels.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Roman Kagan <rkagan@parallels.com>
Message-id: 1430207220-24458-25-git-send-email-den@openvz.org
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'linux-user/cris')
0 files changed, 0 insertions, 0 deletions