[Poppler-bugs] [Bug 68322] pdftops 20 Aug 2013 is about 10% slower than last year

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=68322

--- Comment #2 from William Bader <williambader at hotmail.com> ---
I did the bisect.  It was more complicated than I thought because my laptop
slows the cpu as it warms up from the builds.  (The laptop has a 2.5 GHz
i5-2450M.)

It looks like the performance difference comes from a commit that implemented
bilinear image scaling.  I think that the scaling is important.  When I
disabled it by making Splash::isImageInterpolationRequired() return gFalse,
pdftops runs faster but the results are not as good.  I have attached a screen
capture.
I added debug code, and isImageInterpolationRequired() is called 124 times in
my test file, and many of the images are scaled by almost 1.5 or almost 2.  Is
it worth the effort (or even possible) to make special cases for integral
scaling?

William

results of the bisect

b112602334a5de84ae30c2e90d9bc6d4609f7f96 08 Oct 12 8.455 good
1f4a012f7570ffd2120e3e8c2236de5408f3dda3 01 Mar 13 9.373 bad
f8c1b55e764a6e79b0530fb1be9ee11917f4237e 01 Dec 12 9.476 bad
1969bcd693289eba1138fcaa74a684cb3ff2aefc 13 Nov 12 8.416 good
4ceb3f4f4ca0092e79bb36723a7332b071491666 23 Jun 12 8.484 good
85572b85950ed4e4421f1e61e704e5c250ca27d9 01 Dec 12 9.470 bad
ff9e211cfb60eb820b9b046da546352fa59d7df9 23 Jun 12 8.481 good
beff044e4fdf44e80ad7c75255cb71a83e70a293 27 Nov 12 8.425 good
e6806d893a9a104e3f23d69d0245ad0e4948a409 28 Nov 12 8.474 good
a97aead193a927b91a4e33d7b5d2ba7179e664df 30 Nov 12 9.494 bad

a97aead193a927b91a4e33d7b5d2ba7179e664df is the first bad commit
commit a97aead193a927b91a4e33d7b5d2ba7179e664df
Author: Adrian Johnson <ajohnson at redneon.com>
Date:   Fri Nov 30 21:30:19 2012 +0100
 Splash: Implement bilinear image scaling
 Bug #22138

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/poppler-bugs/attachments/20130820/cea6644c/attachment.html>