与Rails兼容的内存分析工具

I'm looking for some tools that are 1.9.3 compatible that can give me some real world usage numbers on the memory a rails program is taking while being used in development. In a perfect world it would be able to break out that memory usage by class, or some way to tell us what can be tweaked. Please only recommend a tool if you've used it and you endorse it.I'm looking for some tools that are 1.9.3 compa