perf stat: Adjust print unit

The default 'M/sec' unit is not useful if the result is small enough.

Adjust it dynamically according to the value.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1328514285-26232-1-git-send-email-namhyung.kim@lge.com
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-stat.c

@@ -844,12 +844,18 @@ static void abs_printout(int cpu, struct perf_evsel *evsel, double avg)
 
 		fprintf(output, " # %8.3f GHz                    ", ratio);
 	} else if (runtime_nsecs_stats[cpu].n != 0) {
+		char unit = 'M';
+
 		total = avg_stats(&runtime_nsecs_stats[cpu]);
 
 		if (total)
 			ratio = 1000.0 * avg / total;
+		if (ratio < 0.001) {
+			ratio *= 1000;
+			unit = 'K';
+		}
 
-		fprintf(output, " # %8.3f M/sec                  ", ratio);
+		fprintf(output, " # %8.3f %c/sec                  ", ratio, unit);
 	} else {
 		fprintf(output, "                                   ");
 	}