high cpu usage after update to MacVim r179 (Vim 9.1.0)

Steps to reproduce

1. Update to MacVim r179 (Vim 9.1.0)
2. Use it

Expected behaviour

Fairly low CPU usage.

Version of Vim and architecture

MacVim r179 (Vim 9.1.0), arm64

Environment

Operating system: macOS 13.5.2 (22G91)
Arch: arm64

How MacVim was installed

downloaded from github, auto-updated via sparkle

Logs and stack traces

I'll attach a sample taking in Activity Monitor.

I only have 6 windows open. Usually I have way more, and CPU usage is negligible. Now it hovers at around 12%.

I use very few plugins.

Vim configuration where issue is reproducable

No response

Issue has been tested with given configuration

• by running MacVim.app from GUI macOS interface
• by running vim/gvim/etc installed by MacVim
• by running other versions of vim (e.g. /usr/bin/vim)

Issue has been tested with no configuration

• by running mvim --clean (or gvim, supplied by MacVim distribution)
• by running vim --clean (in terminal, supplied by MacVim distribution)
• by running vim --clean (in terminal, other suppliers, e.g. /usr/bin/vim)

Other conditions

• The both Homebrew packages "vim" and "macvim" are installed

Start by reproducing the high CPU usage with MacVim r179 (Vim 9.1.0) on arm64 macOS 13.5.2, then compare the reported GUI behavior with a clean configuration. The issue is resolved when the source of the sustained CPU usage is identified and normal low usage is restored.