Hi, While porting memprof (https://github.com/ice799/memprof) to 1.9, the only change I had do in Ruby itself was to - add hooks for object creation and deletion. Of course, the code still depends heavily on - internal details of how objects are stored in MRI, but I think that is a price - a Profiler writer has to pay anyways. I like the proposal of DTrace as well, but that again means - it will not work on GNU/Linux and other systems where DTrace is not available. Ruby should make it easier to write profilers, what does ruby-core think? -- Let them talk of their oriental summer climes of everlasting conservatories; give me the privilege of making my own summer with my own coals. http://gnufied.org http://twitter.com/gnufied