perf stat: Clean up statistics calculations a bit more

Remove some, now useless, global storage.
Don't calculate the stddev when not needed.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 32b5c00..61b8282 100644 (file)
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -74,7 +74,6 @@ static int                    null_run                        =  0;
 
 static int                     fd[MAX_NR_CPUS][MAX_COUNTERS];
 
-static u64                     event_res[MAX_COUNTERS][3];
 static int                     event_scaled[MAX_COUNTERS];
 
 struct stats
@@ -179,14 +178,12 @@ static inline int nsec_counter(int counter)
  */
 static void read_counter(int counter)
 {
-       u64 *count, single_count[3];
+       u64 count[3], single_count[3];
        unsigned int cpu;
        size_t res, nv;
        int scaled;
        int i;
 
-       count = event_res[counter];
-
        count[0] = count[1] = count[2] = 0;
 
        nv = scale ? 3 : 1;
@@ -318,13 +315,16 @@ static int run_perf_stat(int argc __used, const char **argv)
        return WEXITSTATUS(status);
 }
 
-static void print_noise(double avg, double stddev)
+static void print_noise(int counter, double avg)
 {
-       if (run_count > 1)
-               fprintf(stderr, "   ( +- %7.3f%% )", 100*stddev / avg);
+       if (run_count == 1)
+               return;
+
+       fprintf(stderr, "   ( +- %7.3f%% )",
+                       100 * stddev_stats(&event_res_stats[counter][0]) / avg);
 }
 
-static void nsec_printout(int counter, double avg, double stddev)
+static void nsec_printout(int counter, double avg)
 {
        double msecs = avg / 1e6;
 
@@ -334,10 +334,9 @@ static void nsec_printout(int counter, double avg, double stddev)
                fprintf(stderr, " # %10.3f CPUs ",
                                avg / avg_stats(&walltime_nsecs_stats));
        }
-       print_noise(avg, stddev);
 }
 
-static void abs_printout(int counter, double avg, double stddev)
+static void abs_printout(int counter, double avg)
 {
        fprintf(stderr, " %14.0f  %-24s", avg, event_name(counter));
 
@@ -348,7 +347,6 @@ static void abs_printout(int counter, double avg, double stddev)
                fprintf(stderr, " # %10.3f M/sec",
                                1000.0 * avg / avg_stats(&runtime_nsecs_stats));
        }
-       print_noise(avg, stddev);
 }
 
 /*
@@ -356,12 +354,9 @@ static void abs_printout(int counter, double avg, double stddev)
  */
 static void print_counter(int counter)
 {
-       double avg, stddev;
+       double avg = avg_stats(&event_res_stats[counter][0]);
        int scaled = event_scaled[counter];
 
-       avg    = avg_stats(&event_res_stats[counter][0]);
-       stddev = stddev_stats(&event_res_stats[counter][0]);
-
        if (scaled == -1) {
                fprintf(stderr, " %14s  %-24s\n",
                        "<not counted>", event_name(counter));
@@ -369,9 +364,11 @@ static void print_counter(int counter)
        }
 
        if (nsec_counter(counter))
-               nsec_printout(counter, avg, stddev);
+               nsec_printout(counter, avg);
        else
-               abs_printout(counter, avg, stddev);
+               abs_printout(counter, avg);
+
+       print_noise(counter, avg);
 
        if (scaled) {
                double avg_enabled, avg_running;