GW2 w/ Futex2 on 5.13.1: CoherentUIHost going nuts on CPU usage (~11Cores)

[Atemu]

I have no knowledge or ability to debug this but this did not happen on 5.12, nor does it happen with 5.13.1 when using esync instead.

This makes the game nearly unplayable (low 20s) and stresses the whole CPU for no good reason.

[damentz]

@Atemu this should be fixed now in 5.13/master. We'll need to wait for @heftig to spin another build of linux-zen.

And details of what I did. I'm not entirely sure what was in 5.13/futex2 before, but I believe there were porting errors and missing patches. To fix, I took the v4 patch set [1] (based on 5.13 rc something), and added some proton and basic fixes on top. Did a basic build test and everything's hunky dory.

[1] http://patchwork.sourceware.org/project/glibc/cover/20210603195924.361327-1-andrealmeid@collabora.com/

[Atemu]

Hi @damentz, thanks for looking into this. Unfortunately, it's still happening on 18cfd38 though.

If you want to reproduce this for yourself, GW2's launcher also exhibits this behaviour and can easily be installed via Lutris without downloading the whole 50G game.

[damentz]

@Atemu thanks for giving the updated master branch a shot. I sent André an email asking if he could provide a port of his futex2-proton working branch for v5.13 and pointed him to the problems you found in this issue. Hopefully we can come out of this with a better futex2 than what we have on 5.12 🤞

[damentz]

@Atemu can you try 5.13/master again? Per André's recommendation, he suggested the patch by the linux-tkg folk at https://github.com/Frogging-Family/linux-tkg/blob/master/linux-tkg-patches/5.13/0007-v5.13-futex2_interface.patch.

André pointed out that even though it's based on a much older futex2 patch set, since the futex2 patch is a work-in-progress, it's expected that there'll be regressions as new drafts come out. Or TL;DR, this should work now 🤞

[damentz]

@Atemu Does latest Zen Kernel resolve CPU usage issues with GW2?

[damentz]

I'll mark this issue as resolved. Zen Kernel is now using the same patch set used by TKG and XanMod. If there was an issue with this patch then it would be affecting all kernels. Let me know if there's an issue, otherwise I'm marking this as resolved.

[Atemu]

Yup, it's fixed now. Thanks!