Thanks for the patch I'm excited to try and and see if it has performance benefits, however I found the actual culprit of my keyboard timeout issue, I'm not sure if it's better to report it here or somewhere else, but it does effect only proton games.
Basically it's some issue with IBus, (any version) and recording only made the issue noticeable and much worse. So running killall ibus-daemon or removing ibus entirely seems to work. No more keyboard lag or total disconnect while recording after that.
Maybe proton could avoid hooking with IBus to avoid this, or it could be mentioned somewhere as an issue for distros that include IBus.
proton experimentalx1 2025-07
System info:
Ubuntu 24.10
TKG bore 6.15 kernel
i3wm window manager
apt steam
proton experimental
i9 9900k 128gb ram, 2080 ti
most recent nvidia, and kisak mesa drivers
OS install is a 1TB SSD 500mb/s
Description:
I've noticed when recording a game with replays, saving a large replay causes proton games to either momentarily timeout and hold the last keyboard input for a few moments, or sometimes completely crash and freeze up steam and my system for up to a minute, depending on how large the background operation was.
I've tested and it seems like native games do not have this issue, they appear to behave relatively smoothly even if I spam multiple save recordings at once.
Proton games that I've tested that have this issue:
Titanfall 2
Marvel Rivals
Splitgate 2
and others
Native games I've tried that definitely do NOT have this issue:
Counter-strike 2
Team Fortress 2
It seems to get worse the larger the file is, so if I set my recorder to something like 100+fps and 5+ minutes, (up to 2 gigs) it will be much more likely to crash than a smaller video. But it may have something to do with the memory as well because if the recording is set to a longer replay, the keyboard appears slightly less responsive at all times, as well. Same with simply recording a continuous video.
It also should be a relatively intensive, newer game, so for example borderlands 1 does not appear to crash.
An easy test for me is to write a large dummy file, like
dd if=/dev/zero of=~/test bs=1M count=10000 status=progress
and tab into the game, then some time during or often times right when it's complete, it will make the game unresponsive.
Things I've tried:
messing with dirty ram settings, messing with system IO scheduler, messing with ionice and nice settings.
different kernels (generic + tkg bore)
proton experimental or proton-GE
different versions of Ubuntu
writing to a different drive
different drivers (nvidia/mesa versions)
I also have switched hardware recently, cpu mobo and ram, and the issue was there before the switch and is still here now. The only thing that has not changed is my SSD and Ubuntu install.
it also does NOT happen for any game on my hardware on windows!
what I have NOT tried yet:
trying a different distro like cachy on a new nvme drive that I have to see if the problem is still there
I believe it's a bug, if not with proton, with a way that Ubuntu might interact with proton.