Re: Some git performance measurements..

From: Mike Ralphson <mike.ralphson@gmail.com>
Date: Dec 7, 2007, 16:09 UTC
Message-ID: <e2b179460712070809r4127dc0br8dc20f55b1076501@mail.gmail.com>
In-Reply-To: <Pine.LNX.4.64.0712071348100.27959@racer.site>

On Dec 7, 2007 1:49 PM, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

Show 10 quoted lines

> On Fri, 7 Dec 2007, Mike Ralphson wrote:
>
> > I benchmarked 3 alternative qsorts, qsortG [2] was the fastest on my
> > system but has funky licensing, the NetBSD qsort was middle-range and
> > the glibc one the slowest of the three (but that could be due to it
> > being tuned for a "Sun 4/260"). All of them show over 100x speed
> > improvements on a git-status of my main repo (104s -> ~0.7s)
>
> How is "You may use it in anything you like;" funky licensing?  It is
> effectively public domain.

I did ask what the git licensing policy was (GPL2 or GPL2-compatible) but got no response. The author's wishes state:

 * This code may be reproduced freely provided
 *   - this file is retained unaltered apart from minor
 *     changes for portability and efficiency
 *   - no changes are made to this comment
 *   - any changes that *are* made are clearly flagged
 *   - the _ID string below is altered by inserting, after
 *     the date, the string " altered" followed at your option
 *     by other material. (Exceptions: you may change the name
 *     of the exported routine without changing the ID string.
 *     You may change the values of the macros TRUNC_* and
 *     PIVOT_THRESHOLD without changing the ID string, provided
 *     they remain constants with TRUNC_nonaligned, TRUNC_aligned
 *     and TRUNC_words/WORD_BYTES between 8 and 24, and
 *     PIVOT_THRESHOLD between 32 and 200.)

and they should be respected. "retained unaltered apart from" sounds a little bit more restrictive than we might like. I haven't pinged him about relicensing though. [Edit, I see Linus has just made those points].

> BTW if you need a starting point (easing on your time constraints):
> http://repo.or.cz/w/git/mingw/4msysgit.git?a=commitdiff;h=bba554dd0114dc436cfdd3f17edc836bbaf3d95f

Many thanks, the gmane links I bookmarked are just complaining about wefts producing no weaves or somesuch, so that's helpful. I'll try the mergesort and report back.

Cheers, Mike