Re: [Qemu-devel] [RFC PATCH v8 08/21] cpu: replay instructions sequence

[Paolo Bonzini]

On 16/02/2015 14:37, Pavel Dovgaluk wrote:
>> From: Paolo Bonzini [mailto:address@hidden On Behalf Of Paolo Bonzini
>> On 16/02/2015 14:27, Pavel Dovgaluk wrote:
>>>> From: Paolo Bonzini [mailto:address@hidden On Behalf Of Paolo Bonzini
>>>> On 16/02/2015 13:26, Pavel Dovgaluk wrote:
>>>>>>>>> I think in this case there are no events at all - just reading timers 
>>>>>>>>> values
>>>>>>>>> that were made while recording.
>>>>>>>>> We have to replay these reads by waking iothread.
>>>>>>>
>>>>>>> I think the right place for this is in replay_read_next_clock then.
>>>>> It doesn't fit. Log file is not read until all instructions are executed.
>>>>> And the next read from the file should be performed by iothread which 
>>>>> should
>>>>> be notified and waked up.
>>>>
>>>> I still don't understand.  If you're getting EXCP_INTERRUPT it means:
>>>>
>>>> 1) that cpu_signal was called
>>>
>>> No, it isn't. That is the branch when icount is expired.
>>> And when it is expired in replay mode we have to wake up iothread,
>>> because nobody will care about this.
>>
>> Then it's done here in qemu_tcg_cpu_thread_fn:
> 
> Do you mean that I should put iothread notification right here?

It already notifies the iothread.

> Or that this code duplicates my patch?
> If the second one then I guess that it doesn't help and I need to make 
> additional checks about it.

Yes.  You can modify your patch to do:

     int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
     if (deadline == 0) {
         qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
     }

instead of qemu_notify_event(), and remove these lines from
qemu_tcg_cpu_thread_fn.

Paolo

>>
>>         if (use_icount) {
>>             int64_t deadline = 
>> qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
>>
>>             if (deadline == 0) {
>>                 qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
>>             }
>>         }
>>
>> If you need to move the 4 lines inside the if elsewhere, that I guess it's 
>> okay.
> 
> Pavel Dovgalyuk
> 
> 
>