Path of Exile 2 on Linux (Steam/Proton) – shadercache keeps growing endlessly

Hello,

I’ve noticed a serious issue when playing Path of Exile 2 on Linux Ubuntu 22.04.5 LTS via Steam (Proton). The folder

~/.steam/debian-installation/steamapps/shadercache/


keeps growing constantly while the game is running. The size increases by about 1 MB every second and never gets released.

What makes it even stranger: the cache keeps filling up even when I am staying in old areas that should already be fully loaded. As a result, the disk usage just keeps climbing until I manually clean the folder.

Steps to reproduce:

Launch PoE 2 on Linux Ubuntu 22.04.5 LTS (Steam/Proton).

Play for 10–20 minutes.

Check the shadercache folder – it continuously grows without limit.

This causes my /home partition to lose gigabytes of free space during one play session.

Could you please check this? It seems like shader pre-caching is not being handled correctly.

Thanks!

I have the same problem. Tried deleting them or moving them to another location, but it didn't help.

This game always compiles shaders repeatedly, suspecting that the shader cache doesn't work at all.

Exact same issue, loading times (to or from a map, sometimes even traveling through checkpoints, even back to my own hideout) are in the order of minutes, sometimes over 10+ minutes.

Monitoring the size of all shadercache locations shows:
- `%appdata%/Roaming/Path of Exile 2/ShaderCacheVulkan` at ~900Mb so far (and growing, but very slowly).
- `steamapps/shadercache/2694490` at 65Gb so far, with these subfolder sizes:
- `/fozpipelinesv6`: 58Gb,
- `/mesa_shader_cache_sf`: 895Mb,
- `/nvidiav1`: 6.4Gb,
- `/radv_builtin_shaders`: 1.3Mb

Tried multiple versions of Proton (8 didn't work, 9 works "sometimes", 10 and Experimental run the game just fine, except for the constant compilation of shaders).

After much messing around with this, I ended up disabling the Vulkan layer Steam/Valve uses to "fossilize" shaders with the following environment variable:


DISABLE_VK_LAYER_VALVE_steam_fossilize_1=1


Now, there is no more 3 or 4 parallel compiles of shaders happening constantly, filling up multiple different shader cache directories, there's just one. The `steamapps/shadercache` directories are no longer growing, and the only shader cache being utilized is the "driver's default" location at `$HOME/.cache/nvidia/GLCache/` according to `lsof` on the running game (and the game's own cache as well).

Maps are loading fast again, no longer have to wait 5-8 minutes on a loading screen, game is (finally) playable.