Re: napi_busy_poll

[Olivier Langlois <olivier@trillion01.com>]

On Wed, 2022-02-09 at 11:34 +0800, Hao Xu wrote:
> 在 2022/2/9 上午1:05, Jens Axboe 写道:
> > On 2/8/22 7:58 AM, Olivier Langlois wrote:
> > > Hi,
> > > 
> > > I was wondering if integrating the NAPI busy poll for socket fds
> > > into
> > > io_uring like how select/poll/epoll are doing has ever been
> > > considered?
> > > 
> > > It seems to me that it could be an awesome feature when used
> > > along with
> > > a io_qpoll thread and something not too difficult to add...
> > 
> > Should be totally doable and it's been brought up before, just
> > needs
> > someone to actually do it... Would love to see it.
> > 
> We've done some investigation before, would like to have a try.
> 
Hao,

Let me know if I can help you with coding or testing. I have done very
preliminary investigation too. It doesn't seem like it would be very
hard to implement but I get confused with small details.

For instance, the epoll implementation, unless there is something that
I don't understand, appears to have a serious limitation. It seems like
it would not work correctly if there are sockets associated to more
than 1 NAPI device in the fd set. As far as I am concerned, that
limitation would be ok since in my setup I only use 1 device but if it
was necessary to be better than the epoll implementation, I am not sure
at all how this could be addressed. I do not have enough kernel dev
experience to find easy solutions to those type of issues...

Worse case scenario, I guess that I could give it a shot creating a
good enough implementation for my needs and show it to the list to get
feedback...

Greetings,
Olivier