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Re: [Qemu-devel] [patch 0/5][v2] qcow2: improve I/O performance with cac
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [patch 0/5][v2] qcow2: improve I/O performance with cache=off |
Date: |
Tue, 29 Jul 2008 23:35:28 +0200 |
Le mardi 29 juillet 2008 à 14:15 -0500, Anthony Liguori a écrit :
> Laurent Vivier wrote:
> > These patches improve qcow2 performance when used with cache=off.
> >
> > They modify block-qcow2.c to read/write as many clusters as
> > possible per bdrv_aio_[read|write]().
> >
>
> This patch series looks like a pretty good clean up of the code. The
> perf improvement is a nice side effect too.
>
> I'm a little concerned about how much code this touches though. How
Yes, I know, it's why I split it in several patches: easier to review,
easier to test.
> much testing have you done of these changes? Have you tested all of the
> corner cases (backing files, filling up a disk image, etc.)?
Well, before all I made a lot of review of my modifications, but it must
also be reviewed by other eyes.
My test process was:
qemu-img create test.qcow2 500MB
qemu ... -hda boot.raw -hdb test.qcow2
mkfs /dev/hdb
fsck /dev/hdb
mount /dev/hdb /mnt
cd /mnt
dbench 16
cd
umount /mnt
fsck /dev/hdb
mkfs /dev/hdb
fsck /dev/hdb
mount /dev/hdb /mnt
cd /mnt
tar xvf /root/linux.tar.bz2
cd
umount /mnt
fsck /dev/hdb
mount /mnt
cd /mnt/linux/
make defconfig
make
cd
umount /mnt
fsck /dev/hdb
mount /mnt
cd /mnt/linux
make clean
cd
umount /mnt
fsck /dev/hdb
mount /dev/hdb
cd /mnt
rm -fr linux
cd
umount /mnt
fsck /dev/hdb
mkfs /dev/hdb
fsck /dev/hdb
mount /dev/hdb /mnt
dd if=/dev/zero of=/mnt/file
umount /mnt
fsck /dev/hdb
mount /dev/hdb /mnt
rm /mnt/file
umount /mnt
fsck /dev/hdb
mount /dev/hdb /mnt
cd /mnt
dbench 1
cd
umount /mnt
fsck /dev/hdb
I think it covers a lot of cases, but I didn't test encrypted disk image
and compressed disk image. The case with backed files was tested only
with mkfs/fsck/dbench.
If you think these patches are good candidates to be included, I can
make more tests.
Regards,
Laurent
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"La perfection est atteinte non quand il ne reste rien à
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- [Qemu-devel] [patch 0/5][v2] qcow2: improve I/O performance with cache=off, Laurent Vivier, 2008/07/29
- [Qemu-devel] [patch 1/5][v2] Extract code from get_cluster_offset(), Laurent Vivier, 2008/07/29
- [Qemu-devel] [patch 4/5][v2] Aggregate same type clusters., Laurent Vivier, 2008/07/29
- [Qemu-devel] [patch 3/5][v2] Extract compressing part from alloc_cluster_offset(), Laurent Vivier, 2008/07/29
- [Qemu-devel] [patch 2/5][v2] Divide get_cluster_offset(), Laurent Vivier, 2008/07/29
- [Qemu-devel] [patch 5/5][v2] Try to aggregate free clusters and freed clusters, Laurent Vivier, 2008/07/29
- Re: [Qemu-devel] [patch 0/5][v2] qcow2: improve I/O performance with cache=off, Anthony Liguori, 2008/07/29
- Re: [Qemu-devel] [patch 0/5][v2] qcow2: improve I/O performance with cache=off,
Laurent Vivier <=