Memprof - A Ruby gem for memory profiling
Memprof is a Ruby level memory profiler that can help you find reference leaks in your application. Memprof can also do very lightweight function call tracing to help you figure out which system calls, and library calls your code causes. Ruby memory profiler similar to bleak_house, but without patches to the Ruby VM.
It uses various binary rewriting techniques to insert hooks into the running Ruby process, allowing you to collect data without having to run a patched Ruby installation. Currently, memprof provides data about object allocation, garbage collection, and full dumps of the Ruby heap.
http://memprof.com/ is a hosted service to analyze dumps and it will be free during beta period.