perfcounters: add PERF_COUNT_BUS_CYCLES

Generalize "bus cycles" hw events - and map them to CPU_CLK_Unhalted.Ref
on x86. (which is a good enough approximation)
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/cpu/perf_counter.c

@@ -41,12 +41,13 @@ static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters);
 
 static const int intel_perfmon_event_map[] =
 {
-  [PERF_COUNT_CYCLES]			= 0x003c,
+  [PERF_COUNT_CPU_CYCLES]		= 0x003c,
   [PERF_COUNT_INSTRUCTIONS]		= 0x00c0,
   [PERF_COUNT_CACHE_REFERENCES]		= 0x4f2e,
   [PERF_COUNT_CACHE_MISSES]		= 0x412e,
   [PERF_COUNT_BRANCH_INSTRUCTIONS]	= 0x00c4,
   [PERF_COUNT_BRANCH_MISSES]		= 0x00c5,
+  [PERF_COUNT_BUS_CYCLES]		= 0x013c,
 };
 
 static const int max_intel_perfmon_events = ARRAY_SIZE(intel_perfmon_event_map);

include/linux/perf_counter.h

@@ -36,14 +36,15 @@ enum hw_event_types {
 	/*
 	 * Common hardware events, generalized by the kernel:
 	 */
-	PERF_COUNT_CYCLES		=  0,
+	PERF_COUNT_CPU_CYCLES		=  0,
 	PERF_COUNT_INSTRUCTIONS		=  1,
 	PERF_COUNT_CACHE_REFERENCES	=  2,
 	PERF_COUNT_CACHE_MISSES		=  3,
 	PERF_COUNT_BRANCH_INSTRUCTIONS	=  4,
 	PERF_COUNT_BRANCH_MISSES	=  5,
+	PERF_COUNT_BUS_CYCLES		=  6,
 
-	PERF_HW_EVENTS_MAX		=  6,
+	PERF_HW_EVENTS_MAX		=  7,
 
 	/*
 	 * Special "software" counters provided by the kernel, even if