Fastest way to set files date and time to latest commit time of each one

From: Ivan Baldo <ibaldo@gmail.com>
Date: Aug 29, 2020, 01:36 UTC
Message-ID: <CAEbcw=3mOoYuJo2mQgqB2aJgn-D2i_7ZRmhfPvYNVHD1Kp8wuA@mail.gmail.com>

  Hello.
  I know this is not standard usage of git, but I need a way to have
more stable dates and times in the files in order to avoid rsync
checksumming.
  So I found this
https://stackoverflow.com/questions/2179722/checking-out-old-file-with-original-create-modified-timestamps/2179876#2179876
and modified it a bit to run in CentOS 7:

IFS="
"
for FILE in $(git ls-files -z | tr '\0' '\n')
do
    TIME=$(git log --pretty=format:%cd -n 1 --date=iso -- "$FILE")
    touch -c -m -d "$TIME" "$FILE"
done

  Unfortunately it takes ages for a 84k files repo.
  I see the CPU usage is dominated by the git log command.
  I know a way I could use to split the work for all the CPU threads
but anyway, I would like to know if you guys and girls know of a
faster way to do this.
  Also I know of other utilities that store the metadata in Git, but I
am trying to avoid that for the moment.
  Thanks a lot in advance!
  Have a nice day.
P.s.: please Cc replies to me.

-- 
Ivan Baldo - ibaldo@gmail.com - http://ibaldo.codigolibre.net/
Freelance C++/PHP programmer and GNU/Linux systems administrator.
The sky isn't the limit!