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Re: Looking to improve performance of svn annotate

From: Johan Corveleyn <jcorvel_at_gmail.com>
Date: Fri, 20 Aug 2010 13:40:15 +0200

On Tue, Aug 17, 2010 at 3:26 PM, Johan Corveleyn <jcorvel_at_gmail.com> wrote:
> Another thing that occurred to me: since most time of the current
> blame implementation is spent on "diff" (svn_diff_file_diff_2), maybe
> a quick win could be to simply (?) optimize the diff code? Or write a
> specialized faster version for blame.
>
> On my tests with a 1,5 Mb file (61000 lines), svn diffing it takes
> about 500 ms on my machine. GNU diff is much faster (300 ms for the
> first run, 72 ms on following runs). This seems to indicate that there
> is much room for optimization of svn diff. Or is there something extra
> that svn diff does, necessary in the svn context?
>
> I have looked a little bit at the svn diff code, and saw that most of
> the time is spent in the while loop inside svn_diff__get_tokens in
> token.c, presumably extracting the tokens (lines) from the file(s).
> Haven't looked any further/deeper. Anybody have any brilliant
> ideas/suggestions? Or is this a bad idea, not worthy of further
> exploration :-) ?

As noted in http://svn.haxx.se/dev/archive-2010-08/0517.shtml, my
performance measurements of svn diff were quite inaccurate, to say the
least.

After eliminating antivirus, and running with a release build instead
of a debug build, svn diff is just about on par with GNU diff. So this
eliminates the option of optimizing diff ...

Cheers,

-- 
Johan
Received on 2010-08-20 13:40:53 CEST

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