From: Michał Kępień <michal@isc.org>
Date: Thu, 26 Sep 2019 11:53:03 +0000 (+0200)
Subject: Prevent unbuffered stderr I/O on Windows
X-Git-Tag: v9.14.7~10^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b440d30a78068a4017337690f9811b95ed460d21;p=thirdparty%2Fbind9.git

Prevent unbuffered stderr I/O on Windows

Make stderr fully buffered on Windows to improve named performance when
it is logging to stderr, which happens e.g. in system tests.  Note that:

  - line buffering (_IOLBF) is unavailable on Windows,

  - fflush() is called anyway after each log message gets written to the
    default stderr logging channels created by libisc.

(cherry picked from commit c72da3497d821c06a9b641b1c8544f957c726238)
---

diff --git a/bin/named/main.c b/bin/named/main.c
index c64fb0082b9..7e4273add8f 100644
--- a/bin/named/main.c
+++ b/bin/named/main.c
@@ -1363,6 +1363,17 @@ main(int argc, char *argv[]) {
 	(void) ProfilerStart(NULL);
 #endif
 
+#ifdef WIN32
+	/*
+	 * Prevent unbuffered I/O from crippling named performance on Windows
+	 * when it is logging to stderr (e.g. in system tests).  Use full
+	 * buffering (_IOFBF) as line buffering (_IOLBF) is unavailable on
+	 * Windows and fflush() is called anyway after each log message gets
+	 * written to the default stderr logging channels created by libisc.
+	*/
+	setvbuf(stderr, NULL, _IOFBF, BUFSIZ);
+#endif
+
 	/*
 	 * Record version in core image.
 	 * strings named.core | grep "named version:"