Re: [RFC PATCH v2 00/13] Add futex2 syscall

Am 08.03.21 um 12:11 schrieb David Laight:

From: Stefan Metzmacher

quoted

Sent: 07 March 2021 11:35

Hi André,

quoted

 ** The wait on multiple problem

 The use case lies in the Wine implementation of the Windows NT interface
 WaitMultipleObjects. This Windows API function allows a thread to sleep
 waiting on the first of a set of event sources (mutexes, timers, signal,
 console input, etc) to signal.

They are all events.
You can only wait on either events or sockets (using select).
There is a socket api to signal an event when data arrives (etc).
There is also the insane (these days) restriction of 64 events.

Ok.

quoted

With that in mind would it be good to have some interaction with epoll (and similar calls)?

Or hook something up so that pollwakeup can kick a futex as well
as waking up poll() and adding an event to epoll().

I guess as FUTEX_FD was already there and was removed we can stop this discussion.

If there will every be the need to an async call, I guess a io_uring based one would
be the best...

metze