This small benchmark suite is intended to test the speed of PNG decoding and encoding against different ruby interpreters. You can set the number of runs by passing the N environment variable. You can execute them as rake task or as standalone script.
rake benchmark:encoding rake benchmark:decoding rake benchmark N=10 # Run all of them, using n=10
Use rvm to simply run the tests against different interpreters. Of course, make sure that the chunky_png is installed for all your interpreters.
rvm 1.8.7,1.9.3,rbx rake benchmark N=10
Some of my benchmark (N=50) result on my 2007 iMac can be found in this gist: gist.github.com/495323
ChunkyPNG is a pure Ruby library to handle PNG files. Decoding a PNG requires a lot of integer math and bitwise operations, and moderate use of the unpack method to read binary data. Encoding is a good test for Array#pack, and depending on the encoding options, also requires a lot of calculations. Therefore, the library is a good benchmark candidate for these methods and algorithms. It has been used to improve the Array#pack and String#unpack methods in Rubinius.