perf stat: Print out instructins/cycle metric

Before:

     7549326754  cycles               #    3201.811 M/sec
    10007594937  instructions         #    4244.408 M/sec

After:

     7542051194  cycles               #    3201.996 M/sec
    10007743852  instructions         #    4248.811 M/sec # 1.327 per cycle

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-stat.c

@@ -83,6 +83,7 @@ static __u64			event_scaled[MAX_COUNTERS];
 
 static __u64			runtime_nsecs;
 static __u64			walltime_nsecs;
+static __u64			runtime_cycles;
 
 static void create_perf_stat_counter(int counter)
 {
@@ -177,6 +178,9 @@ static void read_counter(int counter)
 	if (attrs[counter].type == PERF_TYPE_SOFTWARE &&
 		attrs[counter].config == PERF_COUNT_TASK_CLOCK)
 		runtime_nsecs = count[0];
+	if (attrs[counter].type == PERF_TYPE_HARDWARE &&
+		attrs[counter].config == PERF_COUNT_CPU_CYCLES)
+		runtime_cycles = count[0];
 }
 
 /*
@@ -214,6 +218,13 @@ static void print_counter(int counter)
 		if (runtime_nsecs)
 			fprintf(stderr, " # %11.3f M/sec",
 				(double)count[0]/runtime_nsecs*1000.0);
+		if (runtime_cycles &&
+			attrs[counter].type == PERF_TYPE_HARDWARE &&
+				attrs[counter].config == PERF_COUNT_INSTRUCTIONS) {
+
+			fprintf(stderr, " # %1.3f per cycle",
+				(double)count[0] / (double)runtime_cycles);
+		}
 	}
 	if (scaled)
 		fprintf(stderr, "  (scaled from %.2f%%)",