diff --git a/usr.sbin/syslogd/syslog.conf.5 b/usr.sbin/syslogd/syslog.conf.5
index f13f1bf6d5d7..789d63f2277f 100644
--- a/usr.sbin/syslogd/syslog.conf.5
+++ b/usr.sbin/syslogd/syslog.conf.5
@@ -318,6 +318,22 @@ There are five forms:
 .It
 A pathname (beginning with a leading slash).
 Selected messages are appended to the file.
+.Pp
+To ensure that kernel messages are written to disk promptly,
+.Nm
+calls
+.Xr fsync 2
+after writing messages from the kernel.
+Other messages are not synced explicitly.
+You may prefix a pathname with the minus sign,
+.Dq - ,
+to forego syncing the specified file after every kernel message.
+Note that you might lose information if the system crashes
+immediately following a write attempt.
+Nevertheless, using the
+.Dq -
+option may improve performance,
+especially if the kernel is logging many messages.
 .It
 A hostname (preceded by an at
 .Pq Dq @
@@ -422,6 +438,10 @@ security.*						/var/log/security
 
 # Log all writes to /dev/console to a separate file.
 console.*						/var/log/console.log
+
+# Log ipfw messages without syncing after every message.
+!ipfw
+*.*							-/var/log/ipfw
 .Ed
 .Sh IMPLEMENTATION NOTES
 The
diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index a6b3e422842d..44b87952d3f2 100644
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -186,6 +186,8 @@ struct filed {
 	int	f_prevlen;			/* length of f_prevline */
 	int	f_prevcount;			/* repetition cnt of prevline */
 	u_int	f_repeatcount;			/* number of "repeated" msgs */
+	int	f_flags;			/* file-specific flags */
+#define FFLAG_SYNC 0x01
 };
 
 /*
@@ -1150,7 +1152,7 @@ fprintlog(struct filed *f, int flags, const char *msg)
 			f->f_type = F_UNUSED;
 			errno = e;
 			logerror(f->f_un.f_fname);
-		} else if (flags & SYNC_FILE)
+		} else if ((flags & SYNC_FILE) && (f->f_flags & FFLAG_SYNC))
 			(void)fsync(f->f_file);
 		break;
 
@@ -1635,7 +1637,7 @@ static void
 cfline(const char *line, struct filed *f, const char *prog, const char *host)
 {
 	struct addrinfo hints, *res;
-	int error, i, pri;
+	int error, i, pri, syncfile;
 	const char *p, *q;
 	char *bp;
 	char buf[MAXLINE], ebuf[100];
@@ -1783,6 +1785,12 @@ cfline(const char *line, struct filed *f, const char *prog, const char *host)
 	while (*p == '\t' || *p == ' ')
 		p++;
 
+	if (*p == '-') {
+		syncfile = 0;
+		p++;
+	} else
+		syncfile = 1;
+
 	switch (*p) {
 	case '@':
 		(void)strlcpy(f->f_un.f_forw.f_hname, ++p,
@@ -1806,6 +1814,8 @@ cfline(const char *line, struct filed *f, const char *prog, const char *host)
 			logerror(p);
 			break;
 		}
+		if (syncfile)
+			f->f_flags |= FFLAG_SYNC;
 		if (isatty(f->f_file)) {
 			if (strcmp(p, ctty) == 0)
 				f->f_type = F_CONSOLE;