Very cool, detailed slides.<p>I think his notes demonstrate how wildly the 'optimal' settings for a scripting runtime can vary based on use case - 500K slots in a slab makes perfect sense for rails, but 10K also makes pretty good sense for running ruby from the command line to execute a tiny script.<p>One thing that caught my eye - I think according to slide 52, at startup a rails app is using over 3625840 bytes of heap just to represent newline nodes generated from source code? Am I interpreting the data right, or is he just counting the actual nodes and not the RVALUEs attached to them? Kind of funny to think about optimizing memory usage in a rails app by stripping out superfluous newlines.