Bug #2277: Patch: Fix high CPU usage on Kernel#select
http://redmine.ruby-lang.org/issues/show/2277

Author: Zakaria Haris
Status: Open, Priority: Normal
ruby -v: 1.8.6

This bug brought my server down two times.
While my patch for p111 it still exist in p287.

diff -ru ruby-1.8.6-p111.orig/io.c ruby-1.8.6-p111/io.c
--- ruby-1.8.6-p111.orig/io.c	Tue May 22 23:28:10 2007
+++ ruby-1.8.6-p111/io.c	Sun Aug 30 19:08:09 2009
@@ -4802,12 +4802,12 @@
     if (!pending && n == 0) return Qnil; /* returns nil on timeout */
 
     res = rb_ary_new2(3);
-    rb_ary_push(res, rp?rb_ary_new():rb_ary_new2(0));
+    rb_ary_push(res, (rp||pending)?rb_ary_new():rb_ary_new2(0));
     rb_ary_push(res, wp?rb_ary_new():rb_ary_new2(0));
     rb_ary_push(res, ep?rb_ary_new():rb_ary_new2(0));
 
     if (interrupt_flag == 0) {
-	if (rp) {
+	if (rp || pending) {
 	    list = RARRAY(res)->ptr[0];
 	    for (i=0; i< RARRAY(read)->len; i++) {
 		GetOpenFile(rb_io_get_io(RARRAY(read)->ptr[i]), fptr);


----------------------------------------
http://redmine.ruby-lang.org