Oh, oh. Looks like there is some trouble with futex2 and it flopped for Wine: https://bugs.winehq.org/show_bug.cgi?id=50281

Pretty disappointing after all these supposed benefits it promised.

Last edited by Shmerl on 9 Jan 2022 at 11:56 pm UTC

The initial proposal, and I think the correct solution, was for "winesync":

Description: https://www.winehq.org/pipermail/wine-devel/2021-January/179219.html
Implementation: https://repo.or.cz/linux/zf.git/shortlog/refs/heads/winesync

AFAICT the new futex2 syscalls and the usage in Proton is a faster version of esync/fsync but with the same inherent problems.

From the comments, neither solution is good enough and esync is better than fsync anyway when it does help. So why did they even bother pushing that to the kernel?

Last edited by Shmerl on 10 Jan 2022 at 12:53 am UTC

Keep in mind that this was one part of a much larger changeset, the whole futex2 package, which still haven't been merged. Collabora figured they had a better chance to get things upstreamed piecemeal.

This particular syscall, futex_waitv can be quite beneficial in a lot of other circumstances, for native games too, as I understand it.

I would guess that Valve's plans are for short to medium term to improve fsync with this and the other futex2 changes and maybe winesync can be the long term solution?

I guess we'll see, but from Zebediah's comment it sounds like there is no good solution in sight.