Openssl's sha1 is much faster, ~25% even on this crusty 7 year old laptop. On new Intel and
all arm64 machines which have hardware acceleration openssl will be even more dramatically
faster.
shawn@t410s:~/git/git$ time git fsck
Checking object directories: 100% (256/256), done.
warning in tag d6602ec5194c87b0fc87103ca4d67251c76f233a: missingTaggerEntry: invalid format - expected 'tagger' line
Checking objects: 100% (235759/235759), done.
Checking connectivity: 234357, done.
real 0m24.915s
user 0m24.314s
sys 0m0.536s
shawn@t410s:~/git/git$ time ./git-fsck
Checking object directories: 100% (256/256), done.
warning in tag d6602ec5194c87b0fc87103ca4d67251c76f233a: missingTaggerEntry: invalid format - expected 'tagger' line
Checking objects: 100% (235759/235759), done.
Checking connectivity: 234357, done.
real 0m21.264s
user 0m20.695s
sys 0m0.548s