diff --git a/lib/puppet/util/instrumentation/listeners/log.rb b/lib/puppet/util/instrumentation/listeners/log.rb
new file mode 100644
index 000000000..59e9daff9
--- /dev/null
+++ b/lib/puppet/util/instrumentation/listeners/log.rb
@@ -0,0 +1,29 @@
+require 'monitor'
+
+# This is an example instrumentation listener that stores the last
+# 20 instrumented probe run time.
+Puppet::Util::Instrumentation.new_listener(:log) do
+
+  SIZE = 20
+
+  attr_accessor :last_logs
+
+  def initialize
+    @last_logs = {}.extend(MonitorMixin)
+  end
+
+  def notify(label, event, data)
+    return if event == :start
+    log_line = "#{label} took #{data[:finished] - data[:started]}"
+    @last_logs.synchronize {
+      (@last_logs[label] ||= []) << log_line
+      @last_logs[label].shift if @last_logs[label].length > SIZE
+    }
+  end
+
+  def data
+    @last_logs.synchronize {
+      @last_logs.dup
+    }
+  end
+end
\ No newline at end of file
diff --git a/spec/unit/util/instrumentation/listeners/log_spec.rb b/spec/unit/util/instrumentation/listeners/log_spec.rb
new file mode 100755
index 000000000..8359625a1
--- /dev/null
+++ b/spec/unit/util/instrumentation/listeners/log_spec.rb
@@ -0,0 +1,34 @@
+require 'spec_helper'
+require 'puppet/util/instrumentation'
+
+Puppet::Util::Instrumentation.init
+log = Puppet::Util::Instrumentation.listener(:log)
+
+describe log do
+  before(:each) do
+    @log = log.new
+  end
+
+  it "should have a notify method" do
+    @log.should respond_to(:notify)
+  end
+
+  it "should have a data method" do
+    @log.should respond_to(:data)
+  end
+
+  it "should keep data for stop event" do
+    @log.notify(:test, :stop, { :started => Time.at(123456789), :finished => Time.at(123456790)})
+    @log.data.should == {:test=>["test took 1.0"]}
+  end
+
+  it "should not keep data for start event" do
+    @log.notify(:test, :start, { :started => Time.at(123456789)})
+    @log.data.should be_empty
+  end
+
+  it "should not keep more than 20 events per label" do
+    25.times { @log.notify(:test, :stop, { :started => Time.at(123456789), :finished => Time.at(123456790)}) }
+    @log.data[:test].size.should == 20
+  end
+end
\ No newline at end of file