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[Qemu-devel] [PATCH 21/27] block/parallels: no need to flush on each blo
From: |
Denis V. Lunev |
Subject: |
[Qemu-devel] [PATCH 21/27] block/parallels: no need to flush on each block allocation table update |
Date: |
Wed, 11 Mar 2015 13:28:15 +0300 |
>From the point of guest each write to real disk prior to disk barrier
operation could be lost. Therefore there is no problem that "not synced"
new block is lost due to not updated allocation table if QEMU is crashed.
This situation is properly detected and handled now using inuse magic
and in parallels_check
This patch improves writing performance of
qemu-img create -f parallels -o cluster_size=64k ./1.hds 64G
qemu-io -f parallels -c "write -P 0x11 0 1024k" 1.hds
from 45 Mb/sec to 160 Mb/sec on my SSD disk. The gain on rotational media
is much more sufficient, from 800 Kb/sec to 45 Mb/sec.
Signed-off-by: Denis V. Lunev <address@hidden>
Reviewed-by: Roman Kagan <address@hidden>
CC: Kevin Wolf <address@hidden>
CC: Stefan Hajnoczi <address@hidden>
---
block/parallels.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/parallels.c b/block/parallels.c
index bafc74b..2605c1a 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -118,7 +118,7 @@ static int64_t allocate_cluster(BlockDriverState *bs,
int64_t sector_num)
bdrv_truncate(bs->file, (pos + s->tracks) << BDRV_SECTOR_BITS);
s->bat_bitmap[idx] = cpu_to_le32(pos / s->off_multiplier);
- ret = bdrv_pwrite_sync(bs->file,
+ ret = bdrv_pwrite(bs->file,
sizeof(ParallelsHeader) + idx * sizeof(s->bat_bitmap[idx]),
s->bat_bitmap + idx, sizeof(s->bat_bitmap[idx]));
if (ret < 0) {
--
1.9.1
- [Qemu-devel] [PATCH 03/27] block/parallels: switch to bdrv_read, (continued)
- [Qemu-devel] [PATCH 03/27] block/parallels: switch to bdrv_read, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 24/27] block/parallels: delay writing to BAT till bdrv_co_flush_to_os, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 13/27] block/parallels: rename catalog_ names to bat_, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 10/27] block/parallels: support parallels image creation, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 27/27] block/parallels: improve image writing performance further, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 19/27] block/parallels: implement incorrect close detection, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 11/27] iotests, parallels: test for newly created parallels image via qemu-img, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 15/27] block/parallels: keep BAT bitmap data in little endian in memory, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 18/27] block/parallels: implement parallels_check method of block driver, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 21/27] block/parallels: no need to flush on each block allocation table update,
Denis V. Lunev <=
- [Qemu-devel] [PATCH 08/27] block/parallels: _co_writev callback for Parallels format, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 12/27] parallels: change copyright information in the image header, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 04/27] block/parallels: read up to cluster end in one go, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 14/27] block/parallels: create bat2sect helper, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 07/27] block/parallels: replace magic constants 4, 64 with proper sizeofs, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 09/27] iotests, parallels: test for write into Parallels image, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 25/27] block/parallels: add prealloc-mode and prealloc-size open paramemets, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 17/27] block/parallels: move parallels_open/probe to the very end of the file, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 02/27] block/parallels: rename parallels_header to ParallelsHeader, Denis V. Lunev, 2015/03/11
- [Qemu-devel] [PATCH 23/27] block/parallels: create bat_entry_off helper, Denis V. Lunev, 2015/03/11