Reallocate buffers for every run in strlen

Try and avoid influencing performance of neighbouring functions.

ChangeLog

@@ -1,5 +1,8 @@
 2018-08-16  Siddhesh Poyarekar  <[email protected]>
 
+	* benchtests/bench-strlen.c (do_test): Allocate buffers before
+	every strlen call.
+
 	* benchtests/bench-strlen.c: Print performance numbers in json.
 
 2018-08-16  Rajalakshmi Srinivasaraghavan  <[email protected]>

benchtests/bench-strlen.c

@@ -96,20 +96,23 @@ do_test (json_ctx_t *json_ctx, size_t align, size_t len)
   if (align + sizeof(CHAR) * len >= page_size)
     return;
 
-  CHAR *buf = (CHAR *) (buf1);
-
-  for (i = 0; i < len; ++i)
-    buf[align + i] = 1 + 11111 * i % MAX_CHAR;
-  buf[align + len] = 0;
-
   json_element_object_begin (json_ctx);
   json_attr_uint (json_ctx, "length", len);
   json_attr_uint (json_ctx, "alignment", align);
   json_array_begin (json_ctx, "timings");
 
 
   FOR_EACH_IMPL (impl, 0)
-    do_one_test (json_ctx, impl, (CHAR *) (buf + align), len);
+    {
+      CHAR *buf = (CHAR *) (buf1);
+
+      for (i = 0; i < len; ++i)
+	buf[align + i] = 1 + 11111 * i % MAX_CHAR;
+      buf[align + len] = 0;
+
+      do_one_test (json_ctx, impl, (CHAR *) (buf + align), len);
+      alloc_bufs ();
+    }
 
   json_array_end (json_ctx);
   json_element_object_end (json_ctx);