How do I stop Emacs micro-stuttering and high CPU utilization caused by background calls to git?

Question

Using Emacs on Windows, I experiences issues due to background invocations of git.exe. The same issues might apply on Linux, though the more light-weight process calling might make them unnoticable.

Symptoms

• Occassionally, Windows will report that "Git has crashed", regardless of active Desktop window.
• In the Task Manager, one to two git.exe processes appear every few seconds and vanish again.
• In Emacs, random micro-stutters occur.

Diagnosis Attempts

• Using “Process Explorer” (procexp.exe), it can be found that the git.exe processes are subprocesses of Emacs.
• They occur whenever a file inside a git-versioned directory is opened. More such directories → more stuttering.
• Doing M-x trace-function RET call-process RET with four files opened across two git repositories shows upwards of 30 git invocations per cycle. A high number of synchronous calls definitely explains stuttering.

Answer 1

Solution

The problems turned out to be caused by the customization variable auto-revert-check-vc-info.

If this setting is active, the version control software – git in my case – will be invoked every auto-revert-interval seconds (default 5) for each repository, causing the described behavior.

The only solutions I found were to increase the interval (counter-productive) and to disable auto-revert-check-vc-info (acceptable for me).