[master] 7a9c412 Optimize the trivial string case.

[Poul-Henning Kamp]

commit 7a9c412898fa570a1f3d857490c48ad9f97fa7e0
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Mon Nov 13 09:15:09 2017 +0000

    Optimize the trivial string case.

diff --git a/bin/varnishd/cache/cache_shmlog.c b/bin/varnishd/cache/cache_shmlog.c
index c129fa3..cf72726 100644
--- a/bin/varnishd/cache/cache_shmlog.c
+++ b/bin/varnishd/cache/cache_shmlog.c
@@ -334,6 +334,14 @@ VSLbv(struct vsl_log *vsl, enum VSL_tag_e tag, const char *fmt, va_list ap)
 		return;
 	}
 
+	if (!strcmp(fmt, "%s")) {
+		p = va_arg(ap, char *);
+		t.b = p;
+		t.e = strchr(p, '\0');
+		VSLbt(vsl, tag, t);
+		return;
+	}
+
 	mlen = cache_param->vsl_reclen;
 
 	/* Flush if we cannot fit a full size record */