Further improve string bench timing

Further improve the timings of the string benchmarks.  Ensure most take
between 1 and 4 seconds to improve accuracy.  Overall time taken increases
by 35%.  Tested on AArch64.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

	* benchtests/bench-math-inlines.c: Increase iterations.
	* benchtests/bench-memcmp.c: Likewise.
	* benchtests/bench-rawmemchr.c: Likewise.
	* benchtests/bench-strcmp.c: Likewise.
	* benchtests/bench-strcpy_chk.c: Likewise.
	* benchtests/bench-string.h (INNER_LOOP_ITERS8): Add define.
	(INNER_LOOP_ITERS_MEDIUM): Increase iterations.
	(INNER_LOOP_ITERS_SMALL): Likewise.
	* benchtests/bench-strncat.c: Increase iterations.
	* benchtests/bench-strncmp.c: Increase iterations.
	* benchtests/bench-strncpy.c: Reduce iterations for wide strings.
	* benchtests/bench-strrchr.c: Increase iterations.
	* benchtests/bench-strstr.c: Keep iterations unchanged.
	* benchtests/bench-strtod.c: Increase iterations.

ChangeLog

@@ -1,3 +1,20 @@
+2019-06-28  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	* benchtests/bench-math-inlines.c: Increase iterations.
+	* benchtests/bench-memcmp.c: Likewise.
+	* benchtests/bench-rawmemchr.c: Likewise.
+	* benchtests/bench-strcmp.c: Likewise.
+	* benchtests/bench-strcpy_chk.c: Likewise.
+	* benchtests/bench-string.h (INNER_LOOP_ITERS8): Add define.
+	(INNER_LOOP_ITERS_MEDIUM): Increase iterations.
+	(INNER_LOOP_ITERS_SMALL): Likewise.
+	* benchtests/bench-strncat.c: Increase iterations.
+	* benchtests/bench-strncmp.c: Increase iterations.
+	* benchtests/bench-strncpy.c: Reduce iterations for wide strings.
+	* benchtests/bench-strrchr.c: Increase iterations.
+	* benchtests/bench-strstr.c: Keep iterations unchanged.
+	* benchtests/bench-strtod.c: Increase iterations.
+
 2019-06-28  Anton Youdkevitch  <anton.youdkevitch@bell-sw.com>
 
 	* benchtests/bench-memccpy.c: Replace INNER_LOOP_ITERS

benchtests/bench-math-inlines.c

@@ -220,7 +220,7 @@ static void
 do_one_test (json_ctx_t *json_ctx, proto_t test_fn, volatile double *arr,
 	     size_t len, const char *testname)
 {
-  size_t iters = 500;
+  size_t iters = 2048;
   timing_t start, stop, cur;
 
   json_attr_object_begin (json_ctx, testname);

benchtests/bench-memcmp.c

@@ -63,7 +63,7 @@ static void
 do_one_test (json_ctx_t *json_ctx, impl_t *impl, const CHAR *s1,
 	     const CHAR *s2, size_t len, int exp_result)
 {
-  size_t i, iters = INNER_LOOP_ITERS;
+  size_t i, iters = INNER_LOOP_ITERS8;
   timing_t start, stop, cur;
 
   TIMING_NOW (start);

benchtests/bench-rawmemchr.c

@@ -39,7 +39,7 @@ IMPL (generic_rawmemchr, 0)
 static void
 do_one_test (impl_t *impl, const char *s, int c, char *exp_res)
 {
-  size_t i, iters = INNER_LOOP_ITERS_LARGE;
+  size_t i, iters = INNER_LOOP_ITERS_LARGE * 4;
   timing_t start, stop, cur;
   char *res = CALL (impl, s, c);
   if (res != exp_res)

benchtests/bench-strcmp.c

@@ -83,7 +83,7 @@ do_one_test (json_ctx_t *json_ctx, impl_t *impl,
 	     const CHAR *s1, const CHAR *s2,
 	     int exp_result)
 {
-  size_t i, iters = INNER_LOOP_ITERS;
+  size_t i, iters = INNER_LOOP_ITERS8;
   timing_t start, stop, cur;
 
   TIMING_NOW (start);

benchtests/bench-strcpy_chk.c

@@ -77,7 +77,7 @@ do_one_test (impl_t *impl, char *dst, const char *src,
 	     size_t len, size_t dlen)
 {
   char *res;
-  size_t i, iters = INNER_LOOP_ITERS;
+  size_t i, iters = INNER_LOOP_ITERS8;
   timing_t start, stop, cur;
 
   if (dlen <= len)

benchtests/bench-string.h

@@ -125,9 +125,10 @@ extern impl_t __start_impls[], __stop_impls[];
 # define OPT_SEED 10002
 
 # define INNER_LOOP_ITERS 8192
+# define INNER_LOOP_ITERS8 32768
 # define INNER_LOOP_ITERS_LARGE 131072
-# define INNER_LOOP_ITERS_MEDIUM 1024
-# define INNER_LOOP_ITERS_SMALL 32
+# define INNER_LOOP_ITERS_MEDIUM 2048
+# define INNER_LOOP_ITERS_SMALL 256
 
 int ret, do_srandom;
 unsigned int seed;

benchtests/bench-strncat.c

@@ -51,7 +51,7 @@ IMPL (generic_strncat, 0)
 static void
 do_one_test (impl_t *impl, CHAR *dst, const CHAR *src, size_t n)
 {
-  size_t k = STRLEN (dst), i, iters = INNER_LOOP_ITERS;
+  size_t k = STRLEN (dst), i, iters = INNER_LOOP_ITERS8;
   timing_t start, stop, cur;
 
   if (CALL (impl, dst, src, n) != dst)

benchtests/bench-strncmp.c

@@ -73,7 +73,7 @@ static void
 do_one_test (json_ctx_t *json_ctx, impl_t *impl, const CHAR *s1, const CHAR
 	     *s2, size_t n, int exp_result)
 {
-  size_t i, iters = INNER_LOOP_ITERS;
+  size_t i, iters = INNER_LOOP_ITERS8;
   timing_t start, stop, cur;
 
   TIMING_NOW (start);

benchtests/bench-strncpy.c

@@ -54,7 +54,7 @@ typedef CHAR *(*proto_t) (CHAR *, const CHAR *, size_t);
 static void
 do_one_test (impl_t *impl, CHAR *dst, const CHAR *src, size_t len, size_t n)
 {
-  size_t i, iters = INNER_LOOP_ITERS_LARGE;
+  size_t i, iters = INNER_LOOP_ITERS_LARGE * (4 / CHARBYTES);
   timing_t start, stop, cur;
 
   if (CALL (impl, dst, src, n) != STRNCPY_RESULT (dst, len, n))

benchtests/bench-strrchr.c

@@ -56,7 +56,7 @@ static void
 do_one_test (impl_t *impl, const CHAR *s, int c, CHAR *exp_res)
 {
   CHAR *res = CALL (impl, s, c);
-  size_t i, iters = INNER_LOOP_ITERS;
+  size_t i, iters = INNER_LOOP_ITERS8;
   timing_t start, stop, cur;
 
   if (res != exp_res)

benchtests/bench-strstr.c

@@ -131,7 +131,7 @@ IMPL (basic_strstr, 0)
 static void
 do_one_test (impl_t *impl, const char *s1, const char *s2, char *exp_result)
 {
-  size_t i, iters = INNER_LOOP_ITERS_SMALL;
+  size_t i, iters = INNER_LOOP_ITERS_SMALL / 8;
   timing_t start, stop, cur;
   char *res;
 

benchtests/bench-strtod.c

@@ -24,7 +24,7 @@
 #include "bench-timing.h"
 
 #undef INNER_LOOP_ITERS
-#define INNER_LOOP_ITERS 65536
+#define INNER_LOOP_ITERS 131072
 
 static const char *inputs[] =
 {