From: Ingo Molnar <mingo@elte.hu>
To: Pekka Enberg <penberg@kernel.org>
Cc: kvm@vger.kernel.org, Asias He <asias.hejun@gmail.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Prasad Joshi <prasadjoshi124@gmail.com>,
Sasha Levin <levinsasha928@gmail.com>
Subject: Re: [PATCH 0/9] kvm tools, qcow: Improve QCOW performance
Date: Sun, 10 Jul 2011 19:15:43 +0200 [thread overview]
Message-ID: <20110710171543.GA19513@elte.hu> (raw)
In-Reply-To: <1310216563-17503-1-git-send-email-penberg@kernel.org>
* Pekka Enberg <penberg@kernel.org> wrote:
> This series fixes QCOW locking issues and implements delayed metadata writeout.
> This improves performance of writeout to QCOW2 images that don't have clusters
> and L2 tables allocated on-disk.
>
> I tested the series by running
>
> mount -t ext4 /dev/vdb /mnt
> dd if=/dev/zero of=/mnt/tmp
>
> in the guest multiple times for fresly generated QCOW2 image:
>
> dd if=/dev/zero of=fs.ext4 bs=1024k count=512 && mkfs.ext4 -F fs.ext4 && qemu-img convert -O qcow2 fs.ext4 fs.qcow2
>
> which causes worst-case behavior for the current code.
>
> Before:
>
> [ seekwatcher: http://userweb.kernel.org/~penberg/kvm-qcow-delayed/kvm-qcow2-master.png ]
>
> 511229952 bytes (511 MB) copied, 19.906 s, 25.7 MB/s
> 511229952 bytes (511 MB) copied, 20.3168 s, 25.2 MB/s
> 511229952 bytes (511 MB) copied, 20.8078 s, 24.6 MB/s
> 511229952 bytes (511 MB) copied, 21.0889 s, 24.2 MB/s
> 511229952 bytes (511 MB) copied, 20.7833 s, 24.6 MB/s
> 511229952 bytes (511 MB) copied, 20.7536 s, 24.6 MB/s
> 511229952 bytes (511 MB) copied, 20.0312 s, 25.5 MB/s
>
> After:
>
> [ seekwatcher: http://userweb.kernel.org/~penberg/kvm-qcow-delayed/kvm-qcow2-delayed.png ]
>
> 511229952 bytes (511 MB) copied, 7.68312 s, 66.5 MB/s
> 511229952 bytes (511 MB) copied, 7.54065 s, 67.8 MB/s
> 511229952 bytes (511 MB) copied, 9.34749 s, 54.7 MB/s
> 511229952 bytes (511 MB) copied, 9.2421 s, 55.3 MB/s
> 511229952 bytes (511 MB) copied, 9.9364 s, 51.5 MB/s
> 511229952 bytes (511 MB) copied, 10.0337 s, 51.0 MB/s
> 511229952 bytes (511 MB) copied, 9.39502 s, 54.4 MB/s
Just wondering, how does Qemu perform on the same system using the
same image, with comparable settings?
Thanks,
Ingo
next prev parent reply other threads:[~2011-07-10 17:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-09 13:02 [PATCH 0/9] kvm tools, qcow: Improve QCOW performance Pekka Enberg
2011-07-09 13:02 ` [PATCH 1/9] kvm tools, qcow: Rename struct qcow_l2_cache to struct qcow_l2_table Pekka Enberg
2011-07-09 13:02 ` [PATCH 2/9] kvm tools, qcow: Use 'struct qcow_l2_table' instead of untyped array Pekka Enberg
2011-07-09 13:02 ` [PATCH 3/9] kvm tools, qcow: Fix locking issues Pekka Enberg
2011-07-09 13:02 ` [PATCH 4/9] kvm tools, qcow: Introduce qcow_disk_flush() Pekka Enberg
2011-07-09 13:02 ` [PATCH 5/9] kvm tools, qcow: Delayed L1 table writeout Pekka Enberg
2011-07-09 13:02 ` [PATCH 6/9] kvm tools, qcow: Don't fdatasync() L2 " Pekka Enberg
2011-07-09 13:02 ` [PATCH 7/9] kvm tools, qcow: Use big endian order for L2 table entries Pekka Enberg
2011-07-09 13:02 ` [PATCH 8/9] kvm tools, qcow: Delayed L2 table writeout Pekka Enberg
2011-07-09 13:02 ` [PATCH 9/9] kvm tools, qcow: Flush only dirty L2 tables Pekka Enberg
2011-07-10 17:15 ` Ingo Molnar [this message]
2011-07-10 18:08 ` [PATCH 0/9] kvm tools, qcow: Improve QCOW performance Pekka Enberg
2011-07-10 18:17 ` Ingo Molnar
2011-07-10 18:38 ` Pekka Enberg
2011-07-11 9:31 ` Kevin Wolf
2011-07-11 9:41 ` Pekka Enberg
2011-07-11 10:29 ` Kevin Wolf
2011-07-11 10:32 ` Pekka Enberg
2011-07-11 10:36 ` Ingo Molnar
2011-07-11 10:44 ` Pekka Enberg
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