[Midnightbsd-cvs] src [11917] trunk/sys/sys/systm.h: use builtin memset for a speedup on ryzen cpus with small buffer sizes

[laffer1 at midnightbsd.org]

Revision: 11917
          http://svnweb.midnightbsd.org/src/?rev=11917
Author:   laffer1
Date:     2018-07-19 11:53:14 -0400 (Thu, 19 Jul 2018)
Log Message:
-----------
use builtin memset for a speedup on ryzen cpus with small buffer sizes

Modified Paths:
--------------
    trunk/sys/sys/systm.h

Modified: trunk/sys/sys/systm.h
===================================================================
--- trunk/sys/sys/systm.h	2018-07-19 15:49:08 UTC (rev 11916)
+++ trunk/sys/sys/systm.h	2018-07-19 15:53:14 UTC (rev 11917)
@@ -239,6 +239,12 @@
 #define ovbcopy(f, t, l) bcopy((f), (t), (l))
 void	bcopy(const void *from, void *to, size_t len) __nonnull(1) __nonnull(2);
 void	bzero(void *buf, size_t len) __nonnull(1);
+#define bzero(buf, len) ({				\
+	if (__builtin_constant_p(len) && (len) <= 64)	\
+		__builtin_memset((buf), 0, (len));	\
+	else						\
+		bzero((buf), (len));			\
+})
 
 void	*memcpy(void *to, const void *from, size_t len) __nonnull(1) __nonnull(2);
 void	*memmove(void *dest, const void *src, size_t n) __nonnull(1) __nonnull(2);