JRuby: #extend 10x slower in 1.7 w/OpenJDK 1.7?

extend.rb

module A
  def a
  end
end

class C
end

n = 100_000

require 'benchmark'
puts Benchmark.realtime {
  n.times do
    c = C.new.extend A
    c.a
  end
}

__END__

jruby 1.7.0.dev (ruby-1.8.7-p352) (2011-12-19 f404f75) (OpenJDK 64-Bit Server VM 1.7.0-u2-b21) [darwin-amd64-java]
 *** 10.7369999885559 ***

jruby 1.6.5 (ruby-1.8.7-p330) (2011-10-25 9dcd388) (OpenJDK 64-Bit Server VM 1.7.0-u2-b21) [darwin-amd64-java]
1.64599990844727

jruby 1.6.5 (ruby-1.9.2-p136) (2011-10-25 9dcd388) (OpenJDK 64-Bit Server VM 1.7.0-u2-b21) [darwin-amd64-java]
1.4980001449585

jruby 1.7.0.dev (ruby-1.8.7-p352) (2011-12-19 f404f75) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_26) [darwin-x86_64-java]
1.39100003242493

jruby 1.6.5 (ruby-1.8.7-p330) (2011-10-25 9dcd388) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_26) [darwin-x86_64-java]
1.26300001144409

jruby 1.6.5 (ruby-1.9.2-p136) (2011-10-25 9dcd388) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_26) [darwin-x86_64-java]
1.55699992179871

ruby 1.8.7 (2011-06-30 patchlevel 352) [i686-darwin9.8.0]
1.14297199249268

ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin10.8.0]
0.346896