Re: [RFC PATCH 0/3] epoll: read(),write(),ioctl() interface

[Eric Wong <normalperson@yhbt.net>]

Andy Lutomirski <luto@amacapital.net> wrote:
> >> On 02/02/2014 06:17 PM, Nathaniel Yazdani wrote:
> > So are you saying that those features you mentioned are specifically sought
> > after for the kernel? If so I'd like to take a crack at some of them,
> > may as well
> > get some use out of my new knowledge of epoll internals :)
> 
> If by "sought after", you mean "is there at least one epoll user who
> wants them", then yes :)
> 
> I think that EPOLLET and EPOLLONESHOT are giant hacks, and that what
> everyone really wants is the ability to very efficiently toggle events
> on and off.  The ability to do it simultaneously and inexpensively
> with epoll_wait would make it happen.

Everybody using single-threaded epoll, you mean?  I suppose there's
quite a few of those.

I've pondered an epoll_xchg syscall which would behave like *BSD kevent
to satisfy single-threaded users, but never got around to it.  All my
epoll uses are multithreaded w/ oneshot nowadays, so xchg would only
save one syscall per thread.