repository: /home/avi/kvm
branch: master
commit de5397c2a6519db793f4f23e8c058cd7983cbcaf
Author: Avi Kivity <[EMAIL PROTECTED]>
Date: Sun Dec 9 14:50:51 2007 +0200
kvm: testsuite: improve printf() performance
a string I/O instruction is much faster than byte-at-a-time.
Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
diff --git a/user/test/x86/lib/printf.c b/user/test/x86/lib/printf.c
index f13bf0c..5caec24 100644
--- a/user/test/x86/lib/printf.c
+++ b/user/test/x86/lib/printf.c
@@ -1,6 +1,7 @@
#include "printf.h"
#include "smp.h"
#include <stdarg.h>
+#include "string.h"
static struct spinlock lock;
@@ -149,8 +150,9 @@ int snprintf(char *buf, int size, const char *fmt, ...)
void print_serial(const char *buf)
{
- while (*buf)
- asm volatile ("out %%al, $0xf1" : : "a"(*buf++));
+ unsigned long len = strlen(buf);
+
+ asm volatile ("rep/outsb" : "+S"(buf), "+c"(len) : "d"(0xf1));
}
int printf(const char *fmt, ...)
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