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Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance |
Date: |
Thu, 8 Sep 2011 08:56:28 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Sep 07, 2011 at 04:06:51PM -0700, Yehuda Sadeh wrote:
> The following set of patches improve the qemu-img conversion process
> performance. When using a higher latency backend, small writes have a
> severe impact on the time it takes to do image conversion.
> We switch to using async writes, and we avoid splitting writes due to
> holes when the holes are small enough.
>
> Yehuda Sadeh (2):
> qemu-img: async write to block device when converting image
> qemu-img: don't skip writing small holes
>
> qemu-img.c | 34 +++++++++++++++++++++++++++-------
> 1 files changed, 27 insertions(+), 7 deletions(-)
>
> --
> 2.7.5.1
This has nothing to do with the patch itself, but I've been curious
about the existence of both a QEMU and a Linux kernel rbd block driver.
The I/O latency with qemu-img has been an issue for rbd users. But they
have the option of using the Linux kernel rbd block driver, where
qemu-img can take advantage of the page cache instead of performing
direct I/O.
Does this mean you intend to support both QEMU block/rbd.c and Linux
drivers/block/rbd.c? As a user I would go with the Linux kernel driver
instead of the QEMU block driver because it offers page cache and host
block device features. On the other hand a userspace driver is nice
because it does not require privileges.
Stefan
- [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Yehuda Sadeh, 2011/09/07
- [Qemu-devel] [PATCH 1/2] qemu-img: async write to block device when converting image, Yehuda Sadeh, 2011/09/07
- [Qemu-devel] [PATCH 2/2] qemu-img: don't skip writing small holes, Yehuda Sadeh, 2011/09/07
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Kevin Wolf, 2011/09/08
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Sage Weil, 2011/09/08
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Kevin Wolf, 2011/09/09
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Sage Weil, 2011/09/11
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Yehuda Sadeh Weinraub, 2011/09/11
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Yehuda Sadeh Weinraub, 2011/09/12
- Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance, Kevin Wolf, 2011/09/12