Re: git-diff in a worktree is an order of magnitude slower?

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

> I guess the distinction goes back to c06ff4908b (Record ns-timestamps if
> possible, but do not use it without USE_NSEC, 2009-03-04), which details
> some reasons you might not want USE_NSEC. Feels like it ought to be a
> run-time config, though, and maybe even something that gets auto-probed
> by git-init.

I thought for a bit but didn't think of a clean way to auto-probe if
a filesystem loses nanosecond-precision part of .st_Xtime when
"metadata is flushed and later read back in" with reasonable
overhead.  I do not think we want to trigger system-wide sync and/or
dropping of buffer cache ;-)

> Definitely not an area I have looked at much, though, nor thought hard
> about. So there might be gotchas. :)
>
> -Peff