How to debug 100% cpu - python subprocess

Question

While I am working with nvim, I get occasion periods of 100% cpu stems mostly from the Python subprocess of nvim (some other times it is node). It happens when I do nothing in vim.

I tried to do profiling of vim functions, but nothing came up.

Apperently, the python plugins are: coc-python, leaderF, vim-netranger, ycm(disabled prob), vimspector. They are ordered by likelihood from the most likely to the least.

Is there a good way to debug this?

you may have answers if you disclose which python plugins you are using — Mass, Jun 05 '20 at 00:29
I will examine more carefully the open files and ports in activity monitor. — eyal karni, Jun 05 '20 at 00:42
@eyalkarni please edit your question to include these information, it's easier to spot than in the comments — statox, Jun 05 '20 at 10:20
coc_nvim , gitgutter , ALEEvents,
auto_save , gitgutter,
airline_ale — eyal karni, Jun 05 '20 at 20:09
It could be a timer too. Only coc is relevant here in terms of python. — eyal karni, Jun 05 '20 at 20:11
Just updating that I encounter it again: it is run by script_host.py of nvim, no relevant open files — eyal karni, Aug 30 '20 at 22:42

score 3 · Accepted Answer · answered Dec 23 '20 at 09:53

You could use that vimspector you have installed (in another instance of vim) to attach to the python process and get a stack trace.

Debugpy supports attach-by-PID so you do something like this:

python -m debugpy --listen localhost:5678 --pid <pid of the spinning process>

Then use vimspector to attach to it, using the simple remote-attach config.

You should then be able to see what it's doing; from the stack trace you could at least identify the errant plugin and report to the maintainer. I hope it's not one of mine ;)

Of course, you could also use pdb or something :)

How to debug 100% cpu - python subprocess

1 Answers1