Re: [Qemu-devel] [RFC 0/8] arm AioContext with its own timer stuff

[liu ping fan]

On Tue, Jul 23, 2013 at 6:30 PM, Paolo Bonzini <address@hidden> wrote:
> Il 23/07/2013 04:53, liu ping fan ha scritto:
>> The scenior I can figure out is if adopting timeout of poll, then when
>> changing the deadline, we need to invoke poll, and set the new
>> timeout, right?
>
> Yes, you need to call aio_notify so that poll is reinvoked.
>
I try to list the difference between alarm_timer and timeout of poll.
It includes thread-affinity, resolution and easy-use.

Most of all,  thread-affinity
The main issue with alarm timer is the affinity of timer_t with
threads. For linux, SIGEV_THREAD_ID has been supported for a very long
time and we already associate the signal with the specified thread. So
the only issue is left for other unix, we can emulate the affinity by
using SIGEV_THREAD and repost the event to the specified thread.
As to timeout of poll, it has the affinity of threads.

Resolution:
alarm_timer provides higher resolution, but do we care about it?

easy-use:
The reset of the deadline as mentioned.

Finally, I admit timeout of poll will save large chunk of platform-related code.

Thanks and regards,
Pingfan

> Paolo