output

david@david-mirai ~/dev/jruby$ bin/jruby -b -e 'require "yaml"'
  -> builtin/core_ext/symbol
  <- builtin/core_ext/symbol - 39ms
  -> enumerator
  <- enumerator - 3ms
  -> yaml
    -> stringio
    <- stringio - 9ms
    -> yaml/compat
    <- yaml/compat - 15ms
    -> yaml/error
    <- yaml/error - 2ms
    -> yaml/yecht
      -> yecht
      <- yecht - 117ms
      -> yaml/basenode
        -> yaml/ypath
        <- yaml/ypath - 5ms
      <- yaml/basenode - 20ms
    <- yaml/yecht - 147ms
    -> yaml/tag
    <- yaml/tag - 7ms
    -> yaml/stream
    <- yaml/stream - 1ms
    -> yaml/constants
    <- yaml/constants - 3ms
    -> yaml/rubytypes
      -> date
        -> date
        <- date - 0ms
      <- date - 2ms
      -> yaml/compat
      <- yaml/compat - 0ms
    <- yaml/rubytypes - 51ms
    -> yaml/types
      -> yaml/compat
      <- yaml/compat - 0ms
    <- yaml/types - 10ms
  <- yaml - 296ms
Runtime: 313 ms

patch

From a83f8402d598fad87b600e4a2419ee5f6fb82c1d Mon Sep 17 00:00:00 2001
From: David Calavera <[email protected]>
Date: Tue, 24 Nov 2009 15:29:33 +0100
Subject: [PATCH] [PATCH] fixes JRUBY-4268: speed-up yaml/yecht loading

---
 src/org/jruby/Ruby.java      |    2 ++
 src/org/jruby/RubyJRuby.java |    6 ++++++
 2 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/src/org/jruby/Ruby.java b/src/org/jruby/Ruby.java
index 3b09120..b537638 100644
--- a/src/org/jruby/Ruby.java
+++ b/src/org/jruby/Ruby.java
@@ -1396,6 +1396,8 @@ public final class Ruby {
                 runtime.getLoadService().require("jruby/openssl/stub");
             }
         });
+
+        addLazyBuiltin("date.rb", "date", "org.jruby.RubyJRuby$DateLibrary");
         
         String[] builtins = {"yaml", 
                              "yaml/yecht", "yaml/baseemitter", "yaml/basenode", 
diff --git a/src/org/jruby/RubyJRuby.java b/src/org/jruby/RubyJRuby.java
index 0511a95..f0b9c64 100644
--- a/src/org/jruby/RubyJRuby.java
+++ b/src/org/jruby/RubyJRuby.java
@@ -155,6 +155,12 @@ public class RubyJRuby {
         }
     }
 
+    public static class DateLibrary implements Library {
+        public void load(Ruby runtime, boolean wrap) throws IOException {
+            runtime.getLoadService().lockAndRequire("date");
+        }
+    }
+
     /**
      * Utilities library for all those methods that don't need the full 'java' library
      * to be loaded. This is done mostly for performance reasons. For example, for those
-- 
1.6.0.4