Re: [kvm-devel] [patch 2/2] QEMU: decrease console "refresh rate" with -nographic

[Anthony L. <an...@co...>]

Avi Kivity wrote:
> Anders wrote:
>   
>>>> Why not enable SIGIO on stdio input, like the rest of the fd handling in
>>>> qemu?
>>>>       
>>>>         
>>> Thats a possibility, but I think we've now agreed that doing select() with
>>> a timeout is cleaner and possibly half a cent faster.
>>>     
>>>       
>> Since I can only follow this list as a hobby, I managed to miss that
>> discussion. Can somebody point me to the relevant thread, as I would find
>> it interesting?
>>
>>   
>>     
>
> This was off-list.  The point is, that with the iothread we don't need 
> to rely on signals at all (qemu needs signals to break out of the 
> emulation loop, kvm without iothread needs them to exit guest mode, but 
> the iothread can simply sit in select() waiting for an fd to become 
> active (or for aio to complete via a signal).
>   

Why did we ever need sigtimedwait() anyway?  Even if we were select()ing 
within the VCPU context, we should break out of the select() on signal 
delivery.

Regards,

Anthony Liguori