Re: [Qemu-devel] [RFC PATCH v2 00/49] Series short description

[Frederic Konrad <fred.konrad@greensocs.com>]

On 30/07/2014 11:25, Paolo Bonzini wrote:
> Il 30/07/2014 09:44, Pavel Dovgaluk ha scritto:
>>> From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo Bonzini
>>>>> - patch 16 should also use subsections, and perhaps apply to all other
>>>>> CPUs too?
>>>>   We implemented replay only for i386 and ARM. If we'll change other targets, it will not
>>>> add record/replay capabilities to them, but can confuse the reviewers.
>>> Why are these fields only required by record/replay?
>> No, these fields can cause non-determinism for normal execution mode too.
>> But these changes are not related to reverse execution. I can make patches for them
>> and submit them separately, if needed.
> Yes, thanks.  If it causes nondeterminism for normal execution mode too,
> it's better to apply them to all targets.  If possible use a subsection,
> though.
>
>>>>> - patch 27 makes sense but VIRTUAL is used to skip blinking when the VM
>>>>> is stopped
>>>>   Right, this is kind of hack. I haven't found better solution yet.
>>> I think it's okay to use REALTIME, just add runstate_is_running() to the
>>> "if (now >= s->cursor_blink_time)".
>>>
>>> That said, "every read to virtual clock is written to the
>>> replay log" worries me a bit from the point of view of thread-safety.
>>> Do you need to log all reads because you don't use icount?  Reads can
>>> only happen at given points if you use icount, and you could simply log
>>> the icount value at each synchronization point.
>> We made two implementations of virtual clock. One uses host realtime clock
>> and thus should be written into the log. Another one uses icount and calculated
>> in one of the replay modules (similar to regular icount implementation).
>> This patch series contains only first implementation, because it looks more convenient:
>> user does not have to specify icount shift value, when starting the recording or replaying.
> I think from the upstreaming point of view it's better to stick with
> what makes the code simpler.  Start by submitting only the icount-based
> implementation, the other can come later.
>
> Paolo

Hi all,

I think that's actually our implementation cover no?
(http://lists.gnu.org/archive/html/qemu-devel/2014-07/msg00677.html)

Fred