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Re: [Qemu-devel] [PATCH 5/9] mirror: improve performance of mirroring of
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH 5/9] mirror: improve performance of mirroring of empty disk |
Date: |
Wed, 15 Jun 2016 10:19:43 +0100 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Tue, Jun 14, 2016 at 09:20:47PM -0600, Eric Blake wrote:
> On 06/14/2016 09:25 AM, Denis V. Lunev wrote:
> > We should not take into account zero blocks for delay calculations.
> > They are not read and thus IO throttling is not required. In the
> > other case VM migration with 16 Tb QCOW2 disk with 4 Gb of data takes
> > days.
> >
> > Signed-off-by: Denis V. Lunev <address@hidden>
> > Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> > CC: Stefan Hajnoczi <address@hidden>
> > CC: Fam Zheng <address@hidden>
> > CC: Kevin Wolf <address@hidden>
> > CC: Max Reitz <address@hidden>
> > CC: Jeff Cody <address@hidden>
> > CC: Eric Blake <address@hidden>
> > ---
> > block/mirror.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
>
> Seems reasonable, but I'll let others more familiar with throttling give
> the final say.
There is a bounce buffer fallback when !drv->bdrv_co_pwrite_zeroes. In
that case we need to account for the bytes transferred. I don't see
where the patch takes this into account.
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- Re: [Qemu-devel] [PATCH 2/9] mirror: create mirror_dirty_init helper for mirror_run, (continued)
[Qemu-devel] [PATCH 9/9] mirror: replace bdrv_dirty_bitmap with plain hbitmap, Denis V. Lunev, 2016/06/14
[Qemu-devel] [PATCH 8/9] mirror: use synch scheme for drive mirror, Denis V. Lunev, 2016/06/14
Re: [Qemu-devel] [PATCH 0/9] major rework of drive-mirror, Kevin Wolf, 2016/06/15