Sticky plaster approach to temporary workaround high CPU usage (MacOS)

[universemaster]

I've been experimenting with a temporary sticky plaster approach for high CPU use of vale, see #567 and errata-ai/vale-vscode#113

It seems work has begun on sending just the context rather than the full file (in vscode) to vale, which definitely is the best approach to try first.

However, I had already got some way into looking at how to restrict CPU usage on macos in general, and thought I'd share my progress in this discussion.

Install cpulimit:

brew install cpulimit

Create a script called call-vale-with-reduced-cpu.zsh with use of positional parameters, which need escaping in the quoted sh argument:

#!/bin/zsh

sh -c "/path/to/vale --output=JSON \"\$@\" & pid=\$!; cpulimit -l 50 -p \${pid}; wait \$pid" -- $@

Note the -l 50 which limits to cpu to 50%.

Make the script executable

chmod +x script-name.zsh

Then, I can see that I get expected json output in the terminal and cpu is restricted to 50% when I run:

/path/to/call-vale-with-reduced-cpu.zsh measurements.md --config /path/to/.vale.ini

But, here's my current blocker: When I set the following in vscode settings:

"vale.valeCLI.path": "${workspaceFolder}/vale/call-vale-with-reduced-cpu.zsh"

Then, I get SyntaxError: Unexpected token P in JSON at position 7893 in vscode's Vale Output panel, for any file I open (actually I'm no sure vale is even running). Always the same position. I don't know how to debug this or see the exact json that vscode is trying to import (or export?)

I suspect I need to tweak call-vale-with-reduced-cpu.zsh slightly, but cannot work out how?

If it's quick - I'd love to know how to get this approach working (although granted, I think this is a sticky plaster temporary approach, not a "proper fix). However, I don't suggest much time is devoted to this approach: this will only be needed if the other fixes cannot lower the usual CPU usage.

[universemaster]

This approach now works on my Mac with call-vale-with-reduced-cpu.zsh containing:

#!/bin/zsh

cpulimit -l 50 /Users/path/to/vale $@

I don't think this is the best long-term solution, but I'll use it like this until there is a better solution.

[universemaster]

This approach does indeed limit the cpu usage, but since it's common for 5-6 instances of vale to be running at the same time, even setting to 25% for each instance still results in the noisy fan running.

It's worth noting that this probably isn't just a problem of noise, I very much suspect that it runs laptop batteries down fast too.