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Re: [Qemu-devel] [POC] colo-proxy in qemu
From: |
Jason Wang |
Subject: |
Re: [Qemu-devel] [POC] colo-proxy in qemu |
Date: |
Thu, 30 Jul 2015 16:15:52 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 |
On 07/30/2015 04:03 PM, Dr. David Alan Gilbert wrote:
> * Dong, Eddie (address@hidden) wrote:
>>>> A question here, the packet comparing may be very tricky. For example,
>>>> some protocol use random data to generate unpredictable id or
>>>> something else. One example is ipv6_select_ident() in Linux. So COLO
>>>> needs a mechanism to make sure PVM and SVM can generate same random
>>> data?
>>> Good question, the random data connection is a big problem for COLO. At
>>> present, it will trigger checkpoint processing because of the different
>>> random
>>> data.
>>> I don't think any mechanisms can assure two different machines generate the
>>> same random data. If you have any ideas, pls tell us :)
>>>
>>> Frequent checkpoint can handle this scenario, but maybe will cause the
>>> performance poor. :(
>>>
>> The assumption is that, after VM checkpoint, SVM and PVM have identical
>> internal state, so the pattern used to generate random data has high
>> possibility to generate identical data at short time, at least...
> They do diverge pretty quickly though; I have simple examples which
> reliably cause a checkpoint because of simple randomness in applications.
>
> Dave
>
And it will become even worse if hwrng is used in guest.
Re: [Qemu-devel] [POC] colo-proxy in qemu, Dong, Eddie, 2015/07/23
Re: [Qemu-devel] [POC] colo-proxy in qemu, Jason Wang, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Gonglei, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Dong, Eddie, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Dr. David Alan Gilbert, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu,
Jason Wang <=
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Dr. David Alan Gilbert, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Gonglei, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Dr. David Alan Gilbert, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, zhanghailiang, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Dr. David Alan Gilbert, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Yang Hongyang, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Dr. David Alan Gilbert, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Yang Hongyang, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, zhanghailiang, 2015/07/30
- Re: [Qemu-devel] [POC] colo-proxy in qemu, Yang Hongyang, 2015/07/30