Re: [DEMO][PATCH v2 6/5] compat: add a qsort_s() implementation based on GNU's qsort_r(1)

On Wed, Jan 25, 2017 at 07:43:01PM +0100, René Scharfe wrote:

We could track processor time spent and memory allocated in QSORT_S and the
whole program and show a warning at the end if one of the two exceeded, say,
5% of the total, asking nicely to send it to our mailing list.  Would
something like this be useful for other functions or metrics as well?  Would
it be too impolite to use users as telemetry transports?

Frankly, that sounds a bit overboard to me. If people want to profile
there are profiling tools. If we want users to profile on their systems
and send results to us, I think I'd rather give them instructions or a
wrapper script for doing so.

If we find such cases then we'd better fix them for all platforms, e.g. by
importing timsort, no?

Yes, as long as they are strict improvements. I can't think of a case
where some sorting behavior is a matter of opinion, and they'd prefer
Git behave like the rest of their system rather than like Git on other
systems[1].

-Peff

[1] I wonder the same about regex implementations. I generally consider
    our GNU regex fallback to be a strict improvement over system
    versions, at least in terms of features. But I was interested to see
    recently that musl implements pcre-style "\x" as an extension, but
    it _doesn't_ do REG_STARTEND. So it's at tradeoff. They have to use
    the fallback on newer versions of git (to get REG_STARTEND), but
    that means the rest of their system understands "\x" but Git does
    not.