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

Anthony Liguori
2008-04-15T14:20:35Z

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