[PATCH 12/32] perf, x86: Support full width counting

From: Andi Kleen Recent Intel CPUs have a new alternative MSR range for perfctrs that allows writing the full counter width. Enable this range if the hardware reports it using a new capability bit. This lowers overhead of perf stat slightly because it has to do less interrupts to accumulate the c

[PATCH 12/32] perf, x86: Support full width counting

From: Andi Kleen Recent Intel CPUs have a new alternative MSR range for perfctrs that allows writing the full counter width. Enable this range if the hardware reports it using a new capability bit. This lowers overhead of perf stat slightly because it has to do less interrupts to accumulate the c