On Sun, 2008-08-24 at 19:09 +0200, Sven Neumann wrote:
> Thanks for the review. I have committed this change and some other
> cleanups and optimizations to SVN trunk last night. This gives a small
> but noticeable speedup. I hope that my changes did not introduce any new
> bugs, but I am quite confident that I haven't broken anything.

Some informal (approximate) timings with a grayscale image,
13818x8480 pixels (a sketch by Sydney Jones).

before patch:

scale 50% = 18 seconds to freeze-at-end, 31 secs overall
            17 seconds to freeze-at-end, 29 secs overall
      51% = 14 seconds to freeze-at-end, 43 secs overall
            11 seconds to freeze-at-end, 40 secs overall
after patch:

scale 50% = 07 seconds to freeze-at-end, 24 secs overall
            07 seconds to freeze-at-end, 25 secs overall
      51% = 09 seconds to freeze-at-end, 34 secs overall
            10 seconds to freeze-at-end, 35 secs overall

I did the timings more than once.  I have 8G of RAM and a 7G tile
cache size (on Sven's suggestion - it does seem to speed things up)

By "freeze-at-end" I mean that the progress bar stops moving
when it is almost at the very end; my guess is that it's
pushing onto the undo stack and also maybe generating a
thumbnail for the undo history, but that's an uninformed
guess :-)

The speedup for the first part is very noticeable, e.g.
18 secs -> 7 secs, but it makes the "frozen" part more
noticeable, and as a result actually seems slower.

I did not do regression testing, comparing the results, sorry.


Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/
Ankh: irc.sorcery.net irc.gnome.org www.advogato.org

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