diff --git a/Makefile b/Makefile
index 188737b..60fcede 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,16 @@
-.PHONY: test docs
+.PHONY: test docs tags
 
-default: ctags test 
+default: tags test 
 
-all: ctags test dialyzer docs
+all: tags test check docs
 
 test:
 	mix test
 
-ctags:
+tags:
 	ctags -R .
 
-dialyzer:
+check:
 	dialyzer ./ebin --fullpath --no_check_plt -Wno_return
 
 docs:
diff --git a/test/fixtures/hello_ground.txt b/test/fixtures/hello_ground.txt
new file mode 100644
index 0000000..bf6b275
--- /dev/null
+++ b/test/fixtures/hello_ground.txt
@@ -0,0 +1,20 @@
+Another thing that got forgotten was the fact that against all probability a sperm whale had been suddenly been called into existence several miles above the surface of an alien planet.
+And since this is not a naturally tenable position for a whale, this poor innocent creature had very little time to come to terms with its identity as a whale before it then had to come to terms with not being a whale any more.
+This is a complete record of its thought from the moment it began its life till the moment it ended it.
+Ah . . . ! What's happening? it thought.
+Er, excuse me, who am I?
+Hello?
+Why am I here? What's my purpose in life?
+What do I mean by who am I?
+
+
+Oh no, not again.
+Calm down, get a grip now . . . oh! this is an interesting what is it?
+It's sort of . . . yawning, tingling sensation in my . . . my . . . well, I suppose I'd better start finding names for things if I want to make any headway in what for that sake of what I shall call an argument I shall call the world, so let's call it my stomach.
+Good. Ooooh, it's getting quite strong. And hey, what about this whistling roaring sound going past what I'm suddenly going to call my head? Perhaps I can call that . . . wind! Is that a good name? It'll do . . . perhaps I can find a better name for it later when I've found out what it's for.
+It must be something very important because there certainly seems to be a hell of a lot of it. Hey! What's this thing? This . . . let's call it a tail - yeah, tail. Hey! I can really thrash it about pretty good, can't I? Wow! Wow! That feels great! Doesn't seem to achieve very much but I'll probably find out what it's for later on. Now, have I built up any coherent picture of things yet?
+No.
+Never mind, hey, this is really exciting, so much to find out about, so much to look forward to, I'm quite dizzy with anticipation . . . Or is it the wind?
+There really is a lot of that now, isn't there? And wow! Hey! What's this thing suddenly coming toward me very fast? Very, very fast. So big and flat and round, it needs a big wide-sounding name like . . . ow . . . ound . . . round . . . ground! That's it! That's a good name- ground!
+I wonder if it will be friends with me?
+Hello Ground!
diff --git a/test/perf_test.exs b/test/perf_test.exs
new file mode 100644
index 0000000..2b14bcc
--- /dev/null
+++ b/test/perf_test.exs
@@ -0,0 +1,173 @@
+defmodule PerfTest do
+  use ExUnit.Case
+
+  defrecord TestCtxt,
+    rope: nil,
+    extra: [],
+    time: 0
+
+
+  test "10,000 concats" do
+    threshold = 30_000 #30 milliseconds
+    time = build_rope |> build_ctxt |> run(10_000, :concat)
+    IO.puts "\nROPE: 10,000 concats took #{time} microseconds"
+    assert time < threshold, "10,000 concats completed in #{time} microseconds, longer then threshold of #{threshold} microseconds"
+  end
+
+  test "rebalancing 10,000 words" do
+    threshold = 40_000 #40 milliseconds
+    time = build_long_rope |> build_ctxt |> run(1, :rebalance)
+    IO.puts "\nROPE: 10,000 node rebalance took #{time} microseconds"
+    assert time < threshold, "rebalancing worst case 10,000 leaf rope completed in #{time} microseconds, longer then threshold of #{threshold} microseconds"
+  end
+
+  test "1,000 slices on a balanced rope" do
+    threshold = 100_000 #1/10 second
+    time = build_rope |> build_ctxt |> run(1000, :slice)
+    IO.puts "\nROPE: 1,000 slice took #{time} microseconds"
+    assert time < threshold, "1,000 slices on a balanced rope completed in #{time} microseconds, longer then threshold of #{threshold} microseconds"
+  end
+
+  test "100 finds on a balanced rope" do
+    threshold = 500_000 #1/2 second
+    time = build_rope |> build_ctxt |> run(100, :find)
+    IO.puts "\nROPE: 100 find took #{time} microseconds"
+    assert time < threshold, "100 finds on a balanced rope completed in #{time} microseconds, longer then threshold of #{threshold} microseconds"
+  end
+
+  test "string performance" do
+    time = build_text |> build_ctxt |> run(10_000, :concat)
+    IO.puts "\nSTRING: 10,000 concats took #{time} microseconds"
+
+    time = build_text |> build_ctxt |> run(1_000, :slice)
+    IO.puts "\nSTRING: 1,000 slices took #{time} microseconds"
+
+    time = build_text |> build_ctxt |> run(100, :find)
+    IO.puts "\nSTRING: 100 contains? took #{time} microseconds"
+  end
+
+
+  def build_ctxt(rope) do
+    TestCtxt[rope: rope, extra: build_extra]
+  end
+
+  def build_rope do
+    File.stream!("test/fixtures/hello_ground.txt")
+      |> Enum.reduce("", fn(line, rope) -> Rope.concat(rope, line) end)
+      |> Rope.rebalance
+  end
+
+  def build_long_rope() do
+    extra = build_extra
+    Enum.reduce(1..10_000, "", fn(_count, left) ->
+      Rope.concat([left | Enum.take(extra, 1)])
+    end)
+  end
+
+  def build_extra do
+    File.read!("test/fixtures/towels.txt") |> String.split |> Stream.cycle
+  end
+
+  def build_text do
+    File.read!("test/fixtures/hello_ground.txt")
+  end
+
+  def get_timestamp do
+    {mega,sec,micro} = :erlang.now()
+    (mega*1000000+sec)*1000000+micro
+  end
+
+  def run(ctxt, num, op) do
+    finished = Enum.reduce(1..num, ctxt, fn(_count, TestCtxt[rope: rope] = ctxt) ->
+      operation = {op, generate_args(op, ctxt)}
+      time_operation(operation, ctxt)
+    end)
+
+    finished.time
+  end
+
+  def generate_args(:slice, TestCtxt[rope: rope]) 
+  when is_record(rope, Rope) do
+    {:random.uniform(div(rope.length, 2)), :random.uniform(rope.length) + 100}
+  end
+
+  def generate_args(:slice, TestCtxt[rope: text]) 
+  when is_binary(text) do
+    {:random.uniform(div(String.length(text), 2)), :random.uniform(String.length(text)) + 100}
+  end
+
+  def generate_args(:concat, TestCtxt[extra: extra]) do
+    [w] = Enum.take(extra, 1)
+    w
+  end
+
+  def generate_args(:find, _ctxt) do
+    case :random.uniform(6) do
+      1 -> "my"
+      2 -> "your"
+      3 -> "going"
+      4 -> "N/A"
+      5 -> "I"
+      6 -> "You"
+    end
+  end
+
+  def generate_args(opt, _ctxt) do
+     []
+  end
+
+  def time_operation(operation, ctxt) do
+    startTime = get_timestamp
+    newCtxt = execute_operation(operation, ctxt)
+    endTime = get_timestamp
+
+    newCtxt.update_time(fn(total) -> total + (endTime - startTime) end)
+  end
+
+  ###########################
+  # Rope operations
+  ###########################
+  def execute_operation({:slice, {start, len}}, TestCtxt[rope: rope] = ctxt) 
+  when is_record(rope, Rope) do
+    Rope.slice(rope, start, len)
+    ctxt #leaving the context unchanged
+  end
+
+  def execute_operation({:concat, word}, TestCtxt[rope: rope] = ctxt) 
+  when is_record(rope, Rope) do
+    newRope = Rope.concat([rope | [word]])
+    ctxt.rope newRope
+  end
+
+  def execute_operation({:find, term}, TestCtxt[rope: rope] = ctxt) 
+  when is_record(rope, Rope) do
+    Rope.find(rope, term)
+    ctxt #no change, and find returns the index
+  end
+
+  def execute_operation({:rebalance, _args}, TestCtxt[rope: rope] = ctxt) do
+    newRope = Rope.rebalance(rope)
+    ctxt.rope newRope
+  end
+
+  ############################
+  # String operations for comparison
+  ############################
+  def execute_operation({:slice, {start, len}}, TestCtxt[rope: rope] = ctxt) 
+  when is_binary(rope) do
+    String.slice(rope, start, len)
+    ctxt #leaving the context unchanged
+  end
+
+  def execute_operation({:concat, word}, TestCtxt[rope: rope] = ctxt) 
+  when is_binary(rope) do
+    newRope = rope <> word
+    ctxt.rope newRope
+  end
+
+  def execute_operation({:find, term}, TestCtxt[rope: rope] = ctxt) 
+  when is_binary(rope) do
+    String.contains?(rope, term)
+    ctxt #no change, and find returns the index
+  end
+end
diff --git a/test/rope_test.exs b/test/rope_test.exs
index 3a8627b..bfeb4bf 100644
--- a/test/rope_test.exs
+++ b/test/rope_test.exs
@@ -1,5 +1,3 @@
-Code.require_file "test_helper.exs", __DIR__
-
 defmodule RopeTest do
   use ExUnit.Case