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[Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the ba
From: |
Adam Litke |
Subject: |
[Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver |
Date: |
Thu, 07 Jan 2010 09:39:42 -0600 |
Thanks for the ideas and feedback. I will play around with #4 and see
if I can hack up a prototype.
On Thu, 2010-01-07 at 09:22 -0600, Anthony Liguori wrote:
> On 01/07/2010 09:18 AM, Avi Kivity wrote:
> > On 01/07/2010 05:12 PM, Anthony Liguori wrote:
> >>
> >> 3) Make qemu request balloon stats regularly (maybe every 10 seconds)
> >> and display the latest stats with info balloon. This avoids the
> >> problem in #2 but it means that qemu determines the poll rate instead
> >> of a management tool.
> >>
> >> 4) Make info-balloon a proper asynchronous command. We need new
> >> infrastructure to allow a qmp handler to take a callback that can be
> >> used to delay the completion of the command. This addresses all of
> >> the above problems but it introduces a new one. Command completion
> >> now depends on the guest. This potentially could trip up a naive
> >> management tool that doesn't realize that the info-balloon command
> >> may never complete.
> >>
> >> I'm on the fence between 3 and 4 myself.
> >>
> >
> > Can I tip you over to #4? #3 means we have no idea when the stats
> > were generated. With #4, we can't be sure, but it usually be close to
> > when the command returns.
> >
> > The command should include a timeout so a broken guest won't hang a
> > management tool thread.
>
> Generally, timeouts are evil but if we did something like, wait 10
> seconds and if we don't hear a response from the guest, return the last
> data set, I think I would be okay with that. It means we may be
> reporting stale data, but at the same time, the data is coming from a
> guest so it can't be considered authoritative anyway.
>
> Regards,
>
> Anthony Liguori
--
Thanks,
Adam
- [Qemu-devel] [RFD] virtio: Add memory statistics reporting to the balloon driver, Adam Litke, 2010/01/05
- [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Anthony Liguori, 2010/01/07
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Daniel P. Berrange, 2010/01/07
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Adam Litke, 2010/01/07
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Avi Kivity, 2010/01/07
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Anthony Liguori, 2010/01/07
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Luiz Capitulino, 2010/01/07
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Luiz Capitulino, 2010/01/07
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Anthony Liguori, 2010/01/08
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Luiz Capitulino, 2010/01/08
- Re: [Qemu-devel] Re: [RFD] virtio: Add memory statistics reporting to the balloon driver, Adam Litke, 2010/01/08