From 0a35c4b3cab563e3ab1bf5b7b49bf26e0bb7cb04 Mon Sep 17 00:00:00 2001
From: Colin Percival <cperciva@FreeBSD.org>
Date: Fri, 24 Sep 2021 20:20:33 -0700
Subject: [PATCH] loader printf: Profile with TSLOG

Now that the loader tslog code doesn't call printf, we can profile
printf using TSLOG.  On an EC2 c5.xlarge instance, we spend roughly
45 ms here (out of roughly 500 ms), presumably due to the time spent
writing output to the console.

MFC after:	1 week
Sponsored by:	https://www.patreon.com/cperciva
---
 stand/libsa/printf.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/stand/libsa/printf.c b/stand/libsa/printf.c
index 1602a2dc519d..4de547b644dd 100644
--- a/stand/libsa/printf.c
+++ b/stand/libsa/printf.c
@@ -271,6 +271,7 @@ kvprintf(char const *fmt, kvprintf_fn_t *func, void *arg, int radix, va_list ap)
 	char padc;
 	int stop = 0, retval = 0;
 
+	TSENTER();
 	num = 0;
 	if (!func)
 		d = (char *) arg;
@@ -287,8 +288,10 @@ kvprintf(char const *fmt, kvprintf_fn_t *func, void *arg, int radix, va_list ap)
 		padc = ' ';
 		width = 0;
 		while ((ch = (u_char)*fmt++) != '%' || stop) {
-			if (ch == '\0')
+			if (ch == '\0') {
+				TSEXIT();
 				return (retval);
+			}
 			PCHAR(ch);
 		}
 		percent = fmt - 1;