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Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance
From: |
Sage Weil |
Subject: |
Re: [Qemu-devel] [PATCH 0/2] improve qemu-img conversion performance |
Date: |
Sun, 11 Sep 2011 20:14:23 -0700 (PDT) |
On Fri, 9 Sep 2011, Kevin Wolf wrote:
> Am 08.09.2011 18:36, schrieb Sage Weil:
> > On Thu, 8 Sep 2011, Kevin Wolf wrote:
> >> Am 08.09.2011 01:06, schrieb Yehuda Sadeh:
> >>> 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(-)
> >>>
> >>
> >> This doesn't seem to be against git master or the block tree. Please
> >> rebase.
> >>
> >> I think that commit a22f123c may obsolete your patch 2/2.
> >
> > With git.kernel.org down, where should I be looking for the latest
> > upstream?
>
> qemu has never been on kernel.org. The interesting repositories for you are:
>
> * Upstream: git://git.qemu.org/qemu.git master
> * Block development branch: git://repo.or.cz/qemu/kevin.git block
Oh right. I've been working from qemu-kvm.git.
I've done some (still minimal) testing, and it looks like the combination
of a22f123c and the new writeback/flush stuff in librbd gets the same
result as doing async io explicitly from qemu-img.c. Want to take a look,
Yehuda? It still defaults to off, so you'll need to add
rbd_writeback_window=8000000 or similar to the rbd device string.
Thanks!
sage