using multiple CPU/cores

[yeupou]

Hello,

$ convert --version
Version: ImageMagick 6.7.4-0 2012-04-16 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2011 ImageMagick Studio LLC
Features: OpenMP

I'm using convert to build animated GIF (yeah, I know, kind of 1990's). This work fine except that I'm using a multicore computer and seems to me it goes slower than it should:
- only one core appeared to be used, at 100%
- the CPU frequency is not at it's maximum

I did `export MAGICK_THREAD_LIMIT=4` beforehand, it did not help.

I searched on the website. Maybe I missed something obvious, is there any pointer ?

(I found viewtopic.php?f=1&t=9104&start=0 unconclusive)

[fmw42]

depending upon the machine and operation you want to do, sometimes turning off OpenMP (or set the threads to 1) will work faster that with multiple threads.

[anthony]

GIF is also a very hard format to generate as it has VERY limited colors.

See IM Examples, Color Optimizations
http://www.imagemagick.org/Usage/anim_opt/#color_opt

Also see Video to GIF for a specific example of the problems faced.
http://www.imagemagick.org/Usage/video/#gif