From e99735d2b6ff8c2bbbf0dd566f48d0737c52ed3b Mon Sep 17 00:00:00 2001
From: Patrick Pelissier <Patrick.Pelissier@gmail.com>
Date: Sun, 15 Dec 2019 10:01:32 +0100
Subject: [PATCH] Add repeat option for bench

---
 bench/common.c | 28 +++++++++++++++++++++++++---
 bench/common.h |  4 ++--
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/bench/common.c b/bench/common.c
index 9ffec95f..dde846a1 100644
--- a/bench/common.c
+++ b/bench/common.c
@@ -26,8 +26,15 @@
 #include <string.h>
 #include "common.h"
 
+// The global result
 unsigned long g_result;
 
+// The rand value
+#if defined(MULTI_THREAD_MEASURE)
+M_THREAD_ATTR
+#endif
+unsigned int randValue = 0;
+
 void compiler_barrier(void *p)
 {
   // Do nothing, but let the compiler thinks that we did.
@@ -39,6 +46,7 @@ void compiler_barrier(void *p)
 struct parse_opt_s {
   int test_function;
   double from, to, step, grow;
+  unsigned repeat;
   bool graph;
 };
 
@@ -53,6 +61,7 @@ parse_config(struct parse_opt_s *opt, int argc, const char *argv[])
   opt->step = 0.0;
   opt->grow = 1.1;
   opt->graph = false;
+  opt->repeat = 1;
   
   for(int i = 1; i < argc ; i++)
     {
@@ -73,6 +82,9 @@ parse_config(struct parse_opt_s *opt, int argc, const char *argv[])
 	  i++;
 	  opt->grow = strtod(argv[i], &end);
 	  opt->step = 0;
+	} else if (strcmp(argv[i], "--repeat") == 0) {
+	  i++;
+	  opt->repeat = strtol(argv[i], &end, 10);
 	} else if (strcmp(argv[i], "--graph") == 0) {
 	  opt->graph = true;
 	} else {
@@ -89,7 +101,7 @@ parse_config(struct parse_opt_s *opt, int argc, const char *argv[])
       } else {
 	opt->test_function = strtol (argv[i], &end, 10);
 	if (*end != 0) {
-	  fprintf(stderr, "ERROR: Cannot parse %s. Expected integer\n",
+	  fprintf(stderr, "ERROR: Cannot parse %s. Expected function number\n",
 		  argv[i]);
 	  exit(-1);
 	}
@@ -115,6 +127,7 @@ test(const char library[], size_t n, const config_func_t functions[], int argc,
   // NUMBER
   // --from NUMBER --to NUMBER --step NUMBER --grow NUMBER
   // --graph
+  // --repeat N
   struct parse_opt_s arg;
   parse_config(&arg, argc, argv);
   int i = select_config(arg.test_function, n, functions);
@@ -134,14 +147,23 @@ test(const char library[], size_t n, const config_func_t functions[], int argc,
   // Do the bench
   for(double n = from; n <= to ; n = (arg.grow == 0 ? n + arg.step : n * arg.grow))
     {
-      double t;
+      double t = (1.0/0.0);
+      double avg = 0.0;
       if (functions[i].init != NULL)
 	functions[i].init(n);
-      t = test_function(arg.graph ? NULL : functions[i].funcname, (size_t) n, functions[i].func);
+      for(unsigned r = 0; r < arg.repeat; r++) {
+	double t0 = test_function(arg.graph ? NULL : functions[i].funcname, (size_t) n, functions[i].func);
+	t = t0 < t ? t0 : t;
+	avg += t0;
+      }
       if (functions[i].clear != NULL)
 	functions[i].clear();
       if (arg.graph)
 	fprintf(graph_file, "%f %f\n", n, t);
+      else if (arg.repeat > 1) {
+	printf ("%20.20s time %lu ms for n = %lu ***   BEST  ***\n", functions[i].funcname, (unsigned long) t, (unsigned long) n);
+	printf ("%20.20s time %lu ms for n = %lu *** AVERAGE ***\n", functions[i].funcname, (unsigned long) (avg/arg.repeat), (unsigned long) n);
+      }
     }
   if (arg.graph) {
     fclose(graph_file);
diff --git a/bench/common.h b/bench/common.h
index 898afbc3..824bb707 100644
--- a/bench/common.h
+++ b/bench/common.h
@@ -90,11 +90,11 @@ cputime (void)
 extern unsigned long g_result;
 
 // The rand value
-static
+extern
 #if defined(MULTI_THREAD_MEASURE)
 M_THREAD_ATTR
 #endif
-unsigned int randValue = 0;
+unsigned int randValue;
 
 // Pseudo rand value generator.
 // Not very random but sufficient and fast enough for the bench