[raiguard] [2.0.13, Linux] Mouse movement causes slowdown to specific FPS/UPS values

[aedificatori]

After updating to 2.0.13, I started experiencing slowdowns when moving my cursor around the screen, specifically to 30 FPS and/or 30 UPS. It does not happen every time I move my cursor, but it happens sufficiently consistently that I was able to record screen capture of it occurring multiple times. The issue occurs regardless of the input device. I have not seen any issue related to this prior, particularly in my experience playing 2.0 on this machine.

The attached screenshots show no mouse movement, mouse movement resulting in 30 FPS / 60 UPS (screenshot/video labelled type A), and mouse movement resulting in 30 FPS / 30 UPS (screenshot/video labelled type B). The slowdowns do not always bottom out at 30 FPS, but they usually do (70-90% of the time). Slowdowns can occur when the game is running normally, when in the Game menu, or when in the Save menu. The slowdown also occurs on the Main menu screen, causing the simulations in the background to lag noticeably.

The inconsistency in results makes me wonder if it's my machine, but the issue persisted through restarting Factorio + restarting my computer, and I have not updated any other software or drivers recently. I don't see any noticeable spikes in CPU or RAM usage when slowdown occurs. The slowdowns do not seem to occur if Factorio is not the focused window, but I have not tested this as thoroughly as I'd like.

Log and save are attached. And here's a link to the screen recordings: https://drive.google.com/drive/folders/ ... sp=sharing

[aedificatori]

An update -- turning off "Wait for VSync" caused the slowdowns to stop occurring. Still not sure why it suddenly started happening, and why it only occurs with VSync on + mouse movements, but wanted to share this info.

[Edit]: To be absolutely specific: in a new play session today I did see slowdowns when "Wait for VSync" was enabled, and the slowdowns ceased when "Wait for VSync" was disabled.

Tried this based on these threads:
viewtopic.php?t=55974
viewtopic.php?t=93228
https://www.reddit.com/r/factorio/comme ... eans_time/

[aedificatori]

This issue has persisted into 2.0.16, but I have some updates. This seems to be an issue with the Steam version of the game. The standalone version does not exhibit these slowdowns.

Additionally, on the Steam version of 2.0.16 on Linux, even with Wait for VSync disabled there is an erratic per-frame hitch that occurs when the cursor is moved. Steam's own client's graphical settings are dialed all the way down, and I've disabled the Steam overlay - the issue persists regardless.

Lastly, I don't notice any errant increases in CPU usage, GPU usage, RAM usage or VRAM usage when the slowdowns or hitches occur. Performance and resource usage is about the same between the Steam and standalone versions; the only difference is the slowdowns or hitches.

[Edit, ~15 min later] Actually, I updated my firmware and restarted my computer, and now the slowdowns and hitches are occurring on the standalone version of the game as well. Slowdowns when Wait for VSync is enabled + the cursor is moved, and hitches when Wait for VSync is disabled + the cursor is moved.

[yellowbeltroad]

I noticed the same issue with Factorio with Ubuntu 24.04, but it happens other applications as well (even glxgears). I opened a bug report with Ubuntu here.

[aedificatori]

Now on 2.0.21, I am no longer encountering this issue: I can no longer replicate the slowdown (with vsync on) or the per-frame hitching (with vsync off). I tried with glxgears as well to confirm (per yellowbeltroad's comment), and no issues.

I wonder if one of the recent bugfix pushes for Ubuntu must've included the resolution, if no changes were made on the Factorio side for this issue. Thanks yellowbeltroad for filing that bug report with Ubuntu.