It's also worth looking at SystemTap or DTrace, depending on what OS you're running. While strace will allow you to look at an individual process and its childr

It's also worth looking at SystemTap or DTrace, depending on what OS you're running. While strace will allow you to look at an individual process and its children, SystemTap/DTrace will allow you to gather data on system call (and then some) usage system wide. Some examples: - monitor execve() calls system-wide - monitor I/O to a specific file, from any process - measure per-process network usage (note that newer Linux kernels may have other ways of accomplishing some of these tasks that I'm not aware of). I've had a lot of success using SystemTap to look at low-level filesystem performance issues in the kernel. We've run SystemTap scripts on our production filesystem servers for over a year with no problems whatsoever. Edit: formatting