Background BT workers
Background workers (one for an image) are used to accelerate pages start up.
Workers off-line test
To test workers off-line use
security.fileuri.strict_origin_policy = false in Firefox
--allow-file-access --allow-file-access-from-files flags in Chrome.
I can't use workers off-line in mobile Chrome yet.
CSS pixels in Firefox
Firefox uses 1024 CSS pixels for my 1280 pixel screen.
Then it scales fractal images 5/4 times.
Therefore they are (5/4)2 = 1.5 times faster but a bit coarse.
Use layout.css.devPixelsPerPx = 1.0 to set 100% scaling.
Workers performance tests
Sometimes workers are a little slower at start up than
script without workers. But
I get similar execution times, if I press the picture in the center
(i.e. in the second pass). As I remember, I got similar results for
Java JIT compiler.
updated 22 Oct 2013