benchtests: Add benches for memset with 0 value

memset with zero as the value to set is by far the majority value (99%+
for Python3 and GCC).  Add bench-memset-zero-large.c,
bench-memset-zero-walk.c and bench-memset-zero.c to measure memset
implementations for zeroing.

Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/benchtests/bench-bzero.c b/benchtests/bench-bzero.c
index 93ec521725..500b7eba96 100644
--- a/benchtests/bench-bzero.c
+++ b/benchtests/bench-bzero.c
@@ -17,12 +17,25 @@
    <https://www.gnu.org/licenses/>.  */
 
 #define TEST_MAIN
-#define TEST_NAME "bzero"
+#ifdef DO_MEMSET
+# define TEST_NAME "memset"
+#else
+# define TEST_NAME "bzero"
+#endif
 #define MIN_PAGE_SIZE 131072
 #include "bench-string.h"
 
 #include "json-lib.h"
 
+#ifdef DO_MEMSET
+void *generic_memset (void *, int, size_t);
+
+typedef void *(*proto_t) (void *, int, size_t);
+
+IMPL (memset, 1)
+IMPL (generic_memset, 0)
+
+#else
 static void
 memset_zero (void * s, size_t len)
 {
@@ -33,6 +46,7 @@ typedef void (*proto_t) (void *, size_t);
 
 IMPL (bzero, 1)
 IMPL (memset_zero, 0)
+#endif
 
 static void
 do_one_test (json_ctx_t *json_ctx, impl_t *impl, CHAR *s, size_t n)
@@ -43,7 +57,11 @@ do_one_test (json_ctx_t *json_ctx, impl_t *impl, CHAR *s, size_t n)
   TIMING_NOW (start);
   for (i = 0; i < iters; ++i)
     {
+#ifdef DO_MEMSET
+      CALL (impl, s, 0, n);
+#else
       CALL (impl, s, n);
+#endif
     }
   TIMING_NOW (stop);
 
@@ -132,3 +150,13 @@ test_main (void)
 }
 
 #include <support/test-driver.c>
+
+#ifdef DO_MEMSET
+# define libc_hidden_builtin_def(X)
+# define libc_hidden_def(X)
+# define libc_hidden_weak(X)
+# define weak_alias(X,Y)
+# undef MEMSET
+# define MEMSET generic_memset
+# include <string/memset.c>
+#endif