On Tue, 01/20 11:37, Rasmus Villemoes wrote:
> On Tue, Jan 20 2015, Fam Zheng <famz@xxxxxxxxxx> wrote:
>
> > DESCRIPTION
> >
> > The epoll_mod_wait() system call can be seen as an enhanced combination
> > of several epoll_ctl(2) calls, which are followed by an epoll_pwait(2)
> > call. It is superior in two cases:
> >
> > 1) When epoll_ctl(2) are followed by epoll_wait(2), using epoll_mod_wait
> > will save context switches between user mode and kernel mode;
> >
> > 2) When you need higher precision than microsecond for wait timeout.
>
> You probably want to say millisecond.
Yes, you see that I just can't make this right. :)
>
> > struct epoll_mod_cmd {
> [...]
> > };
>
>
> > struct epoll_wait_spec {
> [...]
> > } EPOLL_PACKED;
>
> Either both or none of these should mention that EPOLL_PACKED is in fact
> part of the actual definition. The changelog for 3/6 sorta mentions
> that it's not really needed for epoll_mod_cmd. Why is it necessary for
> either struct?
Yeah. it's probably not really necessary.
>
> > RETURN VALUE
> >
> > When successful, epoll_mod_wait() returns the number of file
> > descriptors ready for the requested I/O, or zero if no file descriptor
> > became ready during the requested timeout milliseconds.
>
> And here, it doesn't make sense to mention a unit, since the new timeout
> is given using struct timespec (this was the whole point, right?).
Right!
Thanks,
Fam
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