Ingo Molnar writes:

Note, i've created a new branch, tip:perfcounters/powerpc, so we can 
keep these things separate and Ben can pull them too. I see there 
was some review feedback - do you want to send a v2 version perhaps?

Kumar's comments seemed to me to be wanting changes to accommodate
code that doesn't exist yet, so I think those changes should be done
later when that code exists and we know exactly what is needed.  So
the current patches are fine as-is IMO.

Paul.