What is an XPerf alternative for Linux and Mac OS X?
Solution 1:
For linux you can combine many tools. top (or htop), iotop, etc. You could also install BSD accounting and use the sa command.
Solution 2:
For OS X, look into dtrace and derived tools (I think fs_usage and sc_usage are related; there's also a Linux port), as well as parts of Apple's Developer Tools such as Shark (see e.g. here and here).