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>

1 files changed, 14 insertions, 17 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 32b5c003f7fc..61b828236c11 100644
--- 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;