High 'idle' CPU usage caused by rendering spinner of background fetch

[reivilibre]

Describe the bug
I noticed my laptop getting hot when I'm not 'doing' anything and realised lazygit is sitting at 60% CPU usage in the background.

I did a perf top -p <PID> and noticed it is spending a lot of CPU time rerendering the screen.

I then noticed that in the corner lazygit is displaying the 'Fetching /' spinner, which updates quite quickly.

This repository has SSH remotes that are not always reachable, so the fetching spinner pretty much stays on all the time.

To Reproduce
Steps to reproduce the behaviour:

1. Add a git remote that is slow to fetch for some reason (e.g. by being offline, without any appropriate timeout)
2. Launch lazygit
3. Observe 'Fetching' spinner and high idle CPU usage

Expected behaviour

Not being so CPU intensive for a background task, I guess

Could also consider a config option to disable fetching from non-origin remotes for example.

Workaround

This setting makes the spinner update very slowly which more or less works around the problem:

gui:
  spinner:
    rate: 5000

(default is 50 ms)

Alternatively, the background fetch mechanism could be disabled in the config.

Screenshots
If applicable, add screenshots to help explain your problem.

Version info:

commit=, build date=, build source=nix, version=0.51.1, os=linux, arch=amd64, git version=2.49.0

git version 2.49.0

Additional context
Add any other context about the problem here.

Note: please try updating to the latest version or manually building the latest master to see if the issue still occurs.

[stefanhaller]

I'll see if we can reduce the amount of work we do for every redraw. From the perf log you posted, it seems most of the work happens inside of tcell, so I'm not sure there's much we can do; still worth investigating.

I also think 50ms is a pretty high default refresh rate, I'd be totally fine with reducing this a bit; 75ms still looks good to my eyes, but maybe that doesn't help enough.

However, I'd be surprised if it's actually lazygit that's responsible for your laptop getting hot. Are you sure it's not the terminal? When I try this on my Mac with either Terminal.app or iTerm2, they both consume much more CPU than lazygit. I recommend Ghostty, it's a lot more efficient.

And finally, we had a bug where lazygit would keep spinning forever when a background fetch fails (#4588), this was fixed in 0.52. I'm not sure if this is affecting you; maybe not, but it's still worth upgrading to the latest version.

Could also consider a config option to disable fetching from non-origin remotes for example.

We do have this:

git:
  fetchAll: false

(It's true by default.)

[reivilibre]

I'm using htop to see the CPU usage and lazygit is the biggest culprit during this spinner action :).

My terminal is Konsole which could well be playing a part too, but I don't see it on the top few processes in htop.

I think increasing the spinner interval would be fair; 50ms feels very fast and from the feeling of other TUI and CLI spinners I've seen in the past, I wouldn't be surprised if 200ms felt more typical honestly.

The bugfix you mention in 0.52 does sound like it might be worthwhile. I'll upgrade and see.

And thanks for letting me know about fetchAll, I didn't realise that's what that meant.