* ext/io/nonblock/nonblock.c (io_nonblock_set): Avoid F_SETFL if

we're not changing the O_NONBLOCK bit. F_SETFL is an expensive
  operation since it needs to affect all processes with the same
  file object.
  The patch is written by Eric Wong. [ruby-core:35556]



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31238 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,11 @@
+Mon Apr  4 22:02:16 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* ext/io/nonblock/nonblock.c (io_nonblock_set): Avoid F_SETFL if
+	  we're not changing the O_NONBLOCK bit. F_SETFL is an expensive
+	  operation since it needs to affect all processes with the same
+	  file object.
+	  The patch is written by Eric Wong. [ruby-core:35556]
+
 Mon Apr  4 21:41:26 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* io.c (rb_io_syswrite): While local FS writes are usually

ext/io/nonblock/nonblock.c

@@ -47,10 +47,16 @@ rb_io_nonblock_p(VALUE io)
 static void
 io_nonblock_set(int fd, int f, int nb)
 {
-    if (nb)
+    if (nb) {
+	if ((f & O_NONBLOCK) != 0)
+	    return;
 	f |= O_NONBLOCK;
-    else
+    }
+    else {
+	if ((f & O_NONBLOCK) == 0)
+	    return;
 	f &= ~O_NONBLOCK;
+    }
     if (fcntl(fd, F_SETFL, f) == -1)
 	rb_sys_fail(0);
 }