Patches to move plugin loading to gem_runner, to speed startup.

jruby-1.5-rubygems-plugins.patch

diff -u -r ../jruby-1.5.1/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb
--- ../jruby-1.5.1/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb	2010-06-06 10:49:08.000000000 -0500
+++ lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb	2010-11-24 01:51:28.000000000 -0600
@@ -76,3 +76,19 @@
 
 end
 
+plugins = Gem.find_files 'rubygems_plugin'
+
+plugins.each do |plugin|
+
+  # Skip older versions of the GemCutter plugin: Its commands are in
+  # RubyGems proper now.
+
+  next if plugin =~ /gemcutter-0\.[0-3]/
+
+  begin
+    load plugin
+  rescue => e
+    warn "error loading #{plugin.inspect}: #{e.message} (#{e.class})"
+  end
+end
+
diff -u -r ../jruby-1.5.1/lib/ruby/site_ruby/1.8/rubygems.rb lib/ruby/site_ruby/1.8/rubygems.rb
--- ../jruby-1.5.1/lib/ruby/site_ruby/1.8/rubygems.rb	2010-06-06 10:49:08.000000000 -0500
+++ lib/ruby/site_ruby/1.8/rubygems.rb	2010-11-24 01:51:10.000000000 -0600
@@ -1100,19 +1100,3 @@
 
 Gem.clear_paths
 
-plugins = Gem.find_files 'rubygems_plugin'
-
-plugins.each do |plugin|
-
-  # Skip older versions of the GemCutter plugin: Its commands are in
-  # RubyGems proper now.
-
-  next if plugin =~ /gemcutter-0\.[0-3]/
-
-  begin
-    load plugin
-  rescue => e
-    warn "error loading #{plugin.inspect}: #{e.message} (#{e.class})"
-  end
-end
-

jruby-1.6-rubygems-plugins.patch

diff --git a/lib/ruby/site_ruby/1.8/rubygems.rb b/lib/ruby/site_ruby/1.8/rubygems.rb
index 665b785..95b2097 100644
--- a/lib/ruby/site_ruby/1.8/rubygems.rb
+++ b/lib/ruby/site_ruby/1.8/rubygems.rb
@@ -1135,6 +1135,3 @@ require 'rubygems/config_file'
 require 'rubygems/custom_require' if gem_disabled or RUBY_VERSION < '1.9'
 
 Gem.clear_paths
-
-Gem.load_plugins
-
diff --git a/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb b/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb
index 07a792d..48c9853 100644
--- a/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb
+++ b/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb
@@ -76,3 +76,4 @@ class Gem::GemRunner
 
 end
 
+Gem.load_plugins
\ No newline at end of file

RubyGems plugin deferral and impact on startup

~/projects/jruby ➔ ls lib/ruby/gems/1.8/gems/ | wc -l
     471

~/projects/jruby ➔ time jruby -rubygems -e 1

real	0m5.079s
user	0m7.375s
sys	0m0.393s

~/projects/jruby ➔ git stash pop --quiet

~/projects/jruby ➔ time jruby -rubygems -e 1

real	0m1.125s
user	0m1.401s
sys	0m0.139s

I've started a thread about this on the rubygems dev list.