Linux-2.6.33.2/Documentation/ABI/testing/sysfs-profiling

What:		/sys/kernel/profile
Date:		September 2008
Contact:	Dave Hansen <dave@linux.vnet.ibm.com>
Description:
		/sys/kernel/profile is the runtime equivalent
		of the boot-time profile= option.

		You can get the same effect running:

			echo 2 > /sys/kernel/profile

		as you would by issuing profile=2 on the boot
		command line.