This patch contains a major rewrite of the perfmon subsystem to
bring it to version 2.0. This version is NOT compatible with the
existing perfmon-1.x version which was in 2.5 and still is in 2.4
kernels. This new codebase brings a lot of new features including
the ability to attach to already running tasks, the ability the
follow clone2, the ability to write your own sampling buffer format
via kernel modules. It is also much more robust than its 1.x
counter-part. This version supports the Itanium, McKinley and
Madison PMUs. This is beta quality code and extensions to the
interface are planned.