vscode with clangd on ubuntu comes to a crawl, freezes and crashes frequently

[MartyMcFlyInTheSky]

In our company we have a few people using ubuntu on HP laptops and when using vscode-clangd on a large codebase the application often slows down massively, oftentimes so much that it completely freezes up. During this time the CPU fan is spinning like crazy, pointing to a potential overheating issue (that might throttle the CPU). Essentially the feeling is that there are a lot of CPU cycles involved in getting the extension to work properly.

However, our other team members using MAC don't seem to have that problem (at least I never heard of them). So it seems to be kinda linux (or ubuntu) specific. I'm opening this more as collection topic to track this issue since I couldn't find it being tracked elsewhere.

System information
Clangd version (from the log, or clangd --version): 18.1.3
clangd extension version: 0.1.33
Operating system: Ubuntu 22.04

[HighCommander4]

How big is the codebase (order of magnitude number of entries in compile_commands.json), and how much memory do the affected systems have?

Clangd's background index can use a lot of memory, so ruling out OOM / thrashing issues is a good first step.

If it really is a CPU rather than memory issue, a good diagnostic step would be to attach a debugger to the clangd process at the time of a freeze and get an all-threads backtrace, and post it for further diagnosis.

[HighCommander4]

Oh I should also mention the -j option if you're not aware of it already:

  -j <uint>                            - Number of async workers used by clangd. Background index also uses this many workers.

Running with a lower -j than the default could help alleviate this sort of issue.

[MartyMcFlyInTheSky]

In theory it's not a bad laptop - some costly hp with 14 CPU cores...
free -h shows me:

               total        used        free      shared  buff/cache   available
Mem:            30Gi       9.0Gi       6.6Gi       2.2Gi        15Gi        19Gi
Swap:          1.9Gi          0B       1.9Gi

And there are 2204 lines in my compile commands.json

I'll try to limit the number of async workers for clangd and report back.