Take these kind of comments to Reddit, you obviously know nothing about Rails and Ruby, especially Rack and Metal.
"Metal components operate outside the realm of the usual Rails timing and logging components, so you don’t get any internal measurements of page performance."
Indeed, I'd never heard of Metal before reading this post. The quote you included is what lead me to wonder why there are not better tools for such a popular development framework as Ruby on Rails.
As that quote states, there doesn't appear to be a profiler as such, but rather a set of "timing and logging components" built into the framework. If it's true, then ruby today is essentially handling profiling the same way PHP did it in 1998. I find that surprising and saddening.
Also, what is the way PHP handles profiling in 2009 ? I haven't developed in php in quite a while, and I admit I never used anything more complicated then the profiling tools built in Zend Studio.
