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[Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_syn
From: |
Michael Tokarev |
Subject: |
[Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes" |
Date: |
Tue, 24 Aug 2010 15:06:51 +0400 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.1.11) Gecko/20100805 Icedove/3.0.6 |
24.08.2010 15:02, Stefan Hajnoczi wrote:
[]
> Sometimes an improvement has a side effect and it makes sense to hold
> back the improvement until the side effect can be resolved. The
> period of time in which users could rely on qcow2 data integrity is
> small to none, I feel reverting the commit makes sense.
And I agree with this.
> QEMU 0.12.5 has qcow2 sync metadata writes in commit
> 37060c28e522843fbf6f7e59af745dfcb05b132c. Was the performance
> regression spotted on 0.12.5 or 0.13?
It started as a debian bugreport ( http://bugs.debian.org/594069 )
which were reported once 0.12.5 entered debian testing. So
it were spotted in 0.12.5, not 0.13. I verfied the bug locally
and indeed, it makes _huge_ difference (0.12.4 vs 0.12.5), --
e.g 600mb mem windows7 hybernation on my machine now takes about
40 minutes to complete instead of ~20 sec in 0.12.4.
I'm reverting whole series (there are 5 patches in total, covering
qcow, qcow2, vmdk and vpc plus infrastructure) for debian 0.12
package. It is sad but there's no other option for now.
/mjt
- [Qemu-devel] [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Kevin Wolf, 2010/08/24
- [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Stefan Hajnoczi, 2010/08/24
- [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes",
Michael Tokarev <=
- [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Kevin Wolf, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Alexander Graf, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Kevin Wolf, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Alexander Graf, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Avi Kivity, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Alexander Graf, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Avi Kivity, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Kevin Wolf, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Avi Kivity, 2010/08/24
- Re: [Qemu-devel] Re: [RFC][STABLE 0.13] Revert "qcow2: Use bdrv_(p)write_sync for metadata writes", Kevin Wolf, 2010/08/24