Re: [Qemu-devel] What is the best commit for record-replay?

[Aleksandr Bezzubikov]

2017-05-02 15:42 GMT+03:00 Igor R <address@hidden>:
>>>>> I'm trying to use the deterministic record/replay feature, and I would
>>>>> like to know which commit I should take to get it work.
>>>>> In RC0 it seems to be broken. I tried pre-MTTCG commit 2421f381dc, as
>>>
>>>> Can you retry with the latest rc? There were some fixes regarding rr since 
>>>> rc0.
>>>
>>>
>>> I've taken 2.9 release, and RR does not seem to work there.
>>> I recorded the boot process of x86 Fedora-21 linux and the replay got
>>> stuck almost immediately.
>>
>> What's your command line?
>>
>> Does it get stuck at the same place each time?
>>
>> Can you boot fine with icount but without record/replay?
>
> Here is the exact scenario:
> - Get 2.9 from git, configure it as follows: "./configure
> --target-list=i386-softmmu --enable-sdl" and  make.
> - Download 
> https://people.debian.org/~aurel32/qemu/i386/debian_squeeze_i386_standard.qcow2
> - Run qemu with the following command line, until login prompt:
> -icount shift=7,rr=record,rrfile=replay.bin -drive
> file=debian_squeeze_i386_standard.qcow2,if=none,id=img-direct -drive
> driver=blkreplay,if=none,image=img-direct,id=img-blkreplay -device
> ide-hd,drive=img-blkreplay -monitor stdio
> - Replay: -icount shift=7,rr=replay,rrfile=replay.bin -drive
> file=debian_squeeze_i386_standard.qcow2,if=none,id=img-direct -drive
> driver=blkreplay,if=none,image=img-direct,id=img-blkreplay -device
> ide-hd,drive=img-blkreplay -monitor stdio
>
> Every time I attempt to replay, QEMU gets stuck at the same EIP, at a
> very early stage.
>
>
>> Can you boot fine with icount but without record/replay?
>
> Yes. I can also enable icount and recording - it also boots fine. The
> problem with the replay.

Hi guys,
Maybe the thread is a bit outdated, but the problem is still relevant.
I've just tried to record and replay WinXP boot process, and I've encountered
exactly the same problem as described above - record is fine, replay
gets stuck early. I use current master.
And I've discovered the second problem - recording makes initial snapshot,
but it doesn't seem to be saved to the disk - replay can't see it.

Hope you've already found the solution (as the last post was on 2 May)
and it's just got missed the mailing list.

>



-- 
Aleksandr Bezzubikov