git non-time-sequential logs

On Mon, Jan 04, 2021 at 08:22:56AM -0800, John Kennedy wrote:
> The git logs in /usr/src aren't time-sequential, so maybe I shouldn't trust
> those dates above (I pulled it ~Jan 3rd and let it compile overnight), but
> I'm going to repull all the sources and recompile, just in case.  I might
> have initiall pulled it during the git conversion and maybe it is confused.

This might be perfectly natural and just new to me, but when I look at the
git logs this morning I see things like this (editing by me):

	commit e5df46055add3bcf074c9ba275ceb4481802ba04 (HEAD -> main, freebsd/main, freebsd/HEAD)
	Author: Emmanuel Vadot <manu_at_FreeBSD.org>
	Date:   Mon Jan 4 17:30:00 2021 +0100

	commit f61a3898bb989edef7ca308043224e495ed78f64
	Author: Emmanuel Vadot <manu_at_freebsd.org>
	Date:   Mon Dec 14 18:56:56 2020 +0100

	commit b6cc69322a77fa778b00db873781be04f26bd2ee
	Author: Emmanuel Vadot <manu_at_freebsd.org>
	Date:   Tue Dec 15 13:50:00 2020 +0100

	commit 4401fa9bf1a3f2a7f2ca04fae9291218e1ca56bf
	Author: Emmanuel Vadot <manu_at_FreeBSD.org>
	Date:   Mon Jan 4 16:23:10 2021 +0100

  This is a fresh clone+pull off of anongit_at_git.FreeBSD.org:src.git.

  I've always assumed that the "Date:" there was when the commit happened,
so they'd be increasing (most recent on top), but I suppose that you might
have developers in branches that are committing to their branch at one
point in time and it's getting merged into current (main) later, but the
original date is preserved?

  I guess I only care because I was trying to use time to bisect the
time I thought the problem might have been introduced.