Fossilize icon indicating copy to clipboard operation
Fossilize copied to clipboard

104GB RAM Usage during "stuck" Processing Vulkan Shaders at 100%

Open hjpaul7 opened this issue 3 weeks ago • 1 comments

Your system information

  • Steam client version (build number or date): 1764106918

  • Distribution (e.g. Ubuntu): Arch

  • Opted into Steam client beta?: Yes

  • Have you checked for system updates?: Yes

  • Steam Logs: steam-logs.tar.gz

  • GPU: Nvidia

Please describe your issue in as much detail as possible:

Steam is spawning multiple processes leading to 104GB RAM usage during "Processing Vulkan Shaders" while being stuck at 100%. I observed this for about 10 minutes and watched it reach 123GB out of 124GB multiple times and froze the system. Processing Vulkan shaders never completed, just sat there at 100% with this insanely high RAM usage.

Steps for reproducing this issue:

  1. Launch Spider-Man 2
  2. Let Vulkan Shaders process
  3. Observe RAM usage and system freeze
Image Image

hjpaul7 avatar Dec 01 '25 01:12 hjpaul7

I think the problem is that fossilize assigns the work into thread buckets statically and not dynamically, resulting in a progress of almost 100% near the end, waiting potentially on a lot of threads finishing just a few work buckets.

But I don't think that it uses 104 GB of RAM. You cannot just summarize the process RAM usage, that's not how fossilize works: Processes share RAM between each other. If possible, enable or look at the PSS column (proportional set size) which is a much better measure for processes sharing RAM. PSS is roughly calculated by adding the private set size plus and the proportional share of any memory it shares with other processes. Technically, it's not possible to calculate the real and exact memory usage of fossilize, it can only be estimated, and that's what PSS does.

kakra avatar Dec 01 '25 13:12 kakra