ruby-prof 使ったこと無いけどあったよ。

# gem install ruby-prof
Select which gem to install for your platform (i386-linux)
1. ruby-prof 0.6.0 (x86-mswin32-60)
2. ruby-prof 0.6.0 (ruby)
3. ruby-prof 0.5.2 (mswin32)
4. ruby-prof 0.5.2 (ruby)
5. Skip this gem
6. Cancel installation