From: Mark Wielaard <mark@klomp.org>
Date: Sun, 3 Jun 2018 07:28:10 +0000 (+0200)
Subject: readelf: Call __fsetlocking (stdout, FSETLOCKING_BYCALLER).
X-Git-Tag: elfutils-0.172~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e635a79cda230b646f70951d7e1f17325443e84d;p=thirdparty%2Felfutils.git

readelf: Call __fsetlocking (stdout, FSETLOCKING_BYCALLER).

We only call printf on stdout from one thread, so we don't need internal
stdio locking for stdout.

On my machine eu-readelf -N --debug-dump=info libxul.so > /dev/null
goes from 65 seconds to 63 seconds.

Signed-off-by: Mark Wielaard <mark@klomp.org>
---

diff --git a/src/ChangeLog b/src/ChangeLog
index cc12d836c..19f421077 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,7 @@
+2018-06-04  Mark Wielaard  <mark@klomp.org>
+
+	* readelf.c (main): Call __fsetlocking (stdout, FSETLOCKING_BYCALLER).
+
 2018-05-31  Mark Wielaard  <mark@klomp.org>
 
 	* readelf.c (print_debug_units): Print the dwo name and id when
diff --git a/src/readelf.c b/src/readelf.c
index 0725313e4..a578b2764 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -35,6 +35,8 @@
 #include <locale.h>
 #include <stdarg.h>
 #include <stdbool.h>
+#include <stdio.h>
+#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
@@ -310,6 +312,9 @@ static void dump_archive_index (Elf *, const char *);
 int
 main (int argc, char *argv[])
 {
+  /* We use no threads here which can interfere with handling a stream.  */
+  (void) __fsetlocking (stdout, FSETLOCKING_BYCALLER);
+
   /* Set locale.  */
   setlocale (LC_ALL, "");