Question about the ahead-behind computation and status

We working with the (enormous) Windows repo, we observed a performance problem in the ahead-behind computation and were considering a few options.

We had a local repo with a local branch that was 150K commits behind the upstream branch[*]. There was a ~20 second different in the run times for these 2 commands:

     $ git status --porcelain=v2
     $ git status --porcelain=v2 --branch

Profiling showed the additional time was spent computing the ahead/behind values for the branch. (The problem is not specific to porcelain V2, that was just the command where we discovered it; for example, there is a similar perf problem in "git branch" vs "git branch -vv".)

I don't want to jump into the graph algorithm at this time, but was wondering about adding a --no-ahead-behind flag (or something similar or a config setting) that would disable the a/b computation during status.

For status V2 output, we could omit the "# branch.ab x y" line. For normal status output, change the prose a/b message to say something like "are [not] up to date".

Thoughts or suggestions ???

Thanks, Jeff

[*] Sadly, the local repo was only about 20 days out of
     date (including the Thanksgiving holidays)....