Re: git-last-modified(1) slower than git-log(1)?

> Hi Gusted,
> 
> Thanks for reaching out.
> 
> You're actually not the first to notice this, and I've been aware of
> this.
> 
> The thing is, you're testing the difference on a single file. For us at
> GitLab, it wasn't very useful to optimize that use-case, because usually
> we want to see the last commit for a bunch of files at once.
> So the use-case for git-last-modified(1) for us has been to replace
> (pseudo code):
> 
> $ FILES=$(git ls-tree $COMMIT $PATH)
> $ foreach $FILE in $FILES; do git log -1 $COMMIT -- $FILE; end
> 
> GitLab is batching files 25 at once, and in my benchmarking, it was
> shown git-last-modified(1) is faster:
> 
> $ git last-modified $COMMIT -- <files
> 
> (I did this benchmarking in our Gitaly component to have a real-world
> experience and you can visit the results at:
> https://gitlab.com/gitlab-org/gitaly/-/merge_requests/7999#note_2850505479
> )
> 
> So we left the door open for future improvement, although I never have
> gotten to it. At some point I was trying to chase down when git-log(1)
> was doing differently, but I never figured it out.
> 
> But this email challenged me already. And with some help of AI, I
> managed to work on some improvements. You can expect a patch series
> soon.
> 
> (Right before sending out this mail I noticed Peff sent out some changes
> as well. I'll coordinate how to combine.)
>