But then with git, there are other challenges. It took me a while to make Magit usable on our codebase (that for various reasons needs to be on the Windows side of the filesystem) - the main culprit were submodules, and someone's bright recommendation to configure git to query submodules when running git status.
Here's the things I did to get Magit status on our large codebase to show in a reasonable time (around 1-2 seconds):
- git config --global core.preloadindex true # This should be defaulted to true, but sometimes might not be; it ensures git operations parallelize looking at index.
- git config --global gc.auto 256 # Reduce GC threshold; didn't do much in my case, but everyone recommends it in case of performance problems on Windows...
- git config status.submoduleSummary false # This did the trick! It significantly cut down time to show status output.
Unfortunately, it turned out that even with submoduleSummary=false, git status still checks if submodules are there, which impacts performance. On the command line, you can use --ignore-submodules argument to solve this, but for Magit, I didn't find an easy way to configure it (and didn't want to defadvice the function that builds the status buffer), so I ended up editing .git/config and adding "ignore = all" to every single submodule entry in that config.
With this, finally, I get around ~1s for Magit status (and about 0.5s for raw git status). It only gets longer if I issue a git command against the same repo from Windows side - git detects the index isn't correct for the platform, and rebuilds it, which takes several seconds.
Final note: if you want to check why Git is running slow on your end, set GIT_TRACE_PERFORMANCE to true before running your command[0], and you'll learn a lot. That's how I discovered submoduleSummary = false doesn't prevent git status from poking submodules.
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[0] - https://git-scm.com/docs/git, ctrl+f GIT_TRACE_PERFORMANCE. Other values are 1, 2 (equivalent to true), or n, where n > 2, to output to a file descriptor instead of stderr.