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Re: [Qemu-devel] live migration vs device assignment (motivation)
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] live migration vs device assignment (motivation) |
Date: |
Tue, 29 Dec 2015 18:46:30 +0200 |
On Tue, Dec 29, 2015 at 01:42:14AM +0800, Lan, Tianyu wrote:
>
>
> On 12/25/2015 8:11 PM, Michael S. Tsirkin wrote:
> >As long as you keep up this vague talk about performance during
> >migration, without even bothering with any measurements, this patchset
> >will keep going nowhere.
> >
>
> I measured network service downtime for "keep device alive"(RFC patch V1
> presented) and "put down and up network interface"(RFC patch V2 presented)
> during migration with some optimizations.
>
> The former is around 140ms and the later is around 240ms.
>
> My patchset relies on the maibox irq which doesn't work in the suspend state
> and so can't get downtime for suspend/resume cases. Will try to get the
> result later.
Interesting. So you sare saying merely ifdown/ifup is 100ms?
This does not sound reasonable.
Is there a chance you are e.g. getting IP from dhcp?
If so that is wrong - clearly should reconfigure the old IP
back without playing with dhcp. For testing, just set up
a static IP.
> >
> >
> >
> >There's Alex's patch that tracks memory changes during migration. It
> >needs some simple enhancements to be useful in production (e.g. add a
> >host/guest handshake to both enable tracking in guest and to detect the
> >support in host), then it can allow starting migration with an assigned
> >device, by invoking hot-unplug after most of memory have been migrated.
> >
> >Please implement this in qemu and measure the speed.
>
> Sure. Will do that.
>
> >I will not be surprised if destroying/creating netdev in linux
> >turns out to take too long, but before anyone bothered
> >checking, it does not make sense to discuss further enhancements.
- Re: [Qemu-devel] live migration vs device assignment (motivation), (continued)
- Re: [Qemu-devel] live migration vs device assignment (motivation), Dr. David Alan Gilbert, 2015/12/10
- Re: [Qemu-devel] live migration vs device assignment (motivation), Alexander Duyck, 2015/12/10
- Re: [Qemu-devel] live migration vs device assignment (motivation), Lan, Tianyu, 2015/12/13
- Re: [Qemu-devel] live migration vs device assignment (motivation), Alexander Duyck, 2015/12/13
- Re: [Qemu-devel] live migration vs device assignment (motivation), Lan Tianyu, 2015/12/25
- Re: [Qemu-devel] live migration vs device assignment (motivation), Michael S. Tsirkin, 2015/12/25
- Re: [Qemu-devel] live migration vs device assignment (motivation), Lan, Tianyu, 2015/12/28
- Re: [Qemu-devel] live migration vs device assignment (motivation),
Michael S. Tsirkin <=
- Re: [Qemu-devel] live migration vs device assignment (motivation), Alexander Duyck, 2015/12/29
- Re: [Qemu-devel] live migration vs device assignment (motivation), Michael S. Tsirkin, 2015/12/29
- Re: [Qemu-devel] live migration vs device assignment (motivation), Alexander Duyck, 2015/12/29
- Re: [Qemu-devel] live migration vs device assignment (motivation), Alexander Duyck, 2015/12/25
- Re: [Qemu-devel] live migration vs device assignment (motivation), Michael S. Tsirkin, 2015/12/27
- Re: [Qemu-devel] live migration vs device assignment (motivation), Alexander Duyck, 2015/12/27
- Re: [Qemu-devel] live migration vs device assignment (motivation), Michael S. Tsirkin, 2015/12/28
- Re: [Qemu-devel] live migration vs device assignment (motivation), Dong, Eddie, 2015/12/27
- Re: [Qemu-devel] live migration vs device assignment (motivation), Alexander Duyck, 2015/12/27
- Re: [Qemu-devel] live migration vs device assignment (motivation), Michael S. Tsirkin, 2015/12/28