Re: [Qemu-devel] [RFC PATCH v3 29/30] replay: improve replay performance

[Paolo Bonzini]

On 12/01/2018 07:13, Pavel Dovgalyuk wrote:
>> From: Paolo Bonzini [mailto:address@hidden
>> On 11/01/2018 14:12, Pavel Dovgalyuk wrote:
>>>> From: Paolo Bonzini [mailto:address@hidden On Behalf Of Paolo Bonzini
>>>> On 11/01/2018 09:27, Pavel Dovgalyuk wrote:
>>>>> +        } else {
>>>>> +            qemu_notify_event();
>>>>> +        }
>>>>
>>>> Before this patch, what would do the qemu_notify_event?
>>>
>>> We tried using qemu_notify_event to wake up the iothread and speedup the 
>>> replay,
>>> when there is no work for vcpu thread to do.
>>
>> But why doesn't the iothread wake up on its own?
> 
> It will wake up by timeout. But with this change this happens sooner and 
> replay goes faster.

If you want replays to ignore timeouts, that should be done by ensuring
that qemu-timer.c passes a zero timeout to main-loop.c.  (It probably
should be optional, too, maybe via -icount sleep).

Paolo