The kernel possesses a wealth of knowledge as to the state of the  system.
 Unfortunately, the key to accessing that information is usually  locked
within the kernel source.  Retrieving it generally means
modifying the kernel, writing your own means to export data to
userspace, recompiling, rebooting, and testing.  To overcome this, we 
demonstrate an existing tool called SystemTap which allows a powerful 
scripting language to inject code anywhere into a stock Linux kernel at 
runtime in order to gather arbitrary statistics and transmit them to 
userspace.  We then plot a course to the eventual goal of using this  tool
to determine a CPU frequency scaling solution.