Re: [PATCH 1/2] blame: large-scale performance rewrite

From: Shawn Pearce <spearce@spearce.org>
Date: Apr 26, 2014, 17:56 UTC
Message-ID: <CAJo=hJs-Nn=o=aGS_3bO9mnxb+urst6JTZf29_qAejBipz_ZHg@mail.gmail.com>
In-Reply-To: <874n1g80dd.fsf@fencepost.gnu.org>

On Sat, Apr 26, 2014 at 10:30 AM, David Kastrup <dak@gnu.org> wrote:

Show 17 quoted lines

> David Kastrup <dak@gnu.org> writes:
>
>> http://repo.or.cz/r/wortliste.git
>> git blame [-M / -C] wortliste
>>
>> The latter one is _really_ taking a severe hit from the O(n^2)
>> algorithms.  If your benchmarks for that one still point mostly to the
>> unpacking, your jgit blame should be fine regarding the stuff
>> I reimplemented.
>
> Here's some example:
>
> dak@lola:/usr/local/tmp/wortliste$ time git blame -n -s wortliste >/tmp/wl1
>
> real    15m47.118s
> user    14m39.928s
> sys     1m1.872s

Hah, this is quite the torture test. git before your patch is taking 22m11s on my laptop to compute this. (This was with default options, I noticed you passed -s to suppress the author formatting.)

Show 5 quoted lines

> dak@lola:/usr/local/tmp/wortliste$ time ../git/git blame -n -s wortliste >/tmp/wl2
>
> real    3m40.947s
> user    2m40.296s
> sys     0m59.440s

Meanwhile JGit computed in 4m30s on the same hardware. So I guess we are "fine". Its still not as fast as I want it to be. :-)