diff --git a/bench/combine_binary.exs b/bench/combine_binary.exs
new file mode 100644
index 00000000..638c5730
--- /dev/null
+++ b/bench/combine_binary.exs
@@ -0,0 +1,37 @@
+defmodule CombineBinary do
+  def binary_join(blocks) do
+    Enum.reduce(blocks, "", fn block, acc -> acc <> block end)
+  end
+
+  # def iolist([block]) do
+  #   block
+  # end
+
+  def iolist(blocks) do
+    blocks
+    |> Enum.reduce([], fn block, acc -> [acc, block] end)
+    |> IO.iodata_to_binary
+  end
+
+  def reverse_join(blocks) do
+    blocks
+    |> Enum.reverse
+    |> Enum.join("")
+  end
+end
+
+block = String.duplicate("block", 100)
+inputs = %{
+  "1" => [:binary.copy(block)],
+  "10" => for(_i <- 0..10, do: :binary.copy(block)),
+  "100" => for(_i <- 0..100, do: :binary.copy(block))
+}
+
+Benchee.run(%{
+      #"reverse_join": &CombineBinary.reverse_join/1,
+      "binary_join": &CombineBinary.binary_join/1,
+      "iolist": &CombineBinary.iolist/1,
+            },
+  inputs: inputs,
+  print: [fast_warning: false]
+)
diff --git a/bench/date_time_compare.exs b/bench/date_time_compare.exs
new file mode 100644
index 00000000..4da75e10
--- /dev/null
+++ b/bench/date_time_compare.exs
@@ -0,0 +1,20 @@
+smaller = DateTime.from_unix!(1_234_567)
+bigger = DateTime.from_unix!(1_234_568)
+much_bigger = DateTime.from_unix!(9_867_543)
+
+inputs = %{
+  "close": {smaller, bigger},
+  "close reversed": {bigger, smaller},
+  "far": {smaller, much_bigger},
+  "far reversed": {much_bigger, smaller}
+}
+Benchee.run(
+  %{
+    "enum": fn {smaller, bigger} -> Enum.min_by([smaller, bigger], &DateTime.to_unix/1) end,
+    "apply": fn {smaller, bigger} -> apply(Enum, :min_by, [[smaller, bigger], &DateTime.to_unix/1]) end,
+    "compare": fn {smaller, bigger} -> if DateTime.compare(smaller, bigger) == :lt, do: smaller, else: bigger end
+  },
+  time: 5,
+  inputs: inputs,
+  print: [fast_warning: false]
+)
diff --git a/bench/drop_nil_values.exs b/bench/drop_nil_values.exs
new file mode 100644
index 00000000..e6d1e50b
--- /dev/null
+++ b/bench/drop_nil_values.exs
@@ -0,0 +1,54 @@
+defmodule DropNilValues do
+  def reordered(map) do
+    :maps.fold(
+      fn
+        _k, v, acc when not is_nil(v) -> acc
+        k, nil, acc -> Map.delete(acc, k)
+      end,
+      map,
+      map
+    )
+  end
+
+  def delete(map) do
+    :maps.fold(
+      fn
+        k, nil, acc -> Map.delete(acc, k)
+        _k, _v, acc -> acc
+      end,
+      map,
+      map
+    )
+  end
+
+  def original(map) do
+    :maps.fold(
+      fn
+        _k, nil, acc -> acc
+        k, v, acc -> Map.put(acc, k, v)
+      end,
+      %{},
+      map
+    )
+  end
+end
+
+Benchee.run(
+  %{
+    reordered: &DropNilValues.reordered/1,
+    delete: &DropNilValues.delete/1,
+    original: &DropNilValues.original/1
+  },
+  print: [fast_warning: false],
+  inputs: %{
+    third_nils_big: Map.new(0..10, fn i ->
+      if div(i, 3) == 0, do: {i, i}, else: {i, nil}
+    end),
+    quarter_nils_big: Map.new(0..10, fn i ->
+      if div(i, 4) == 0, do: {i, i}, else: {i, nil}
+    end),
+    half_nils_big: Map.new(0..10, fn i ->
+      if div(i, 2) == 0, do: {i, i}, else: {i, nil}
+    end)
+  }
+)
diff --git a/bench/group.exs b/bench/group.exs
new file mode 100644
index 00000000..a20a23e2
--- /dev/null
+++ b/bench/group.exs
@@ -0,0 +1,14 @@
+data = Concentrate.Parser.GTFSRealtime.parse(File.read!("/tmp/TripDescriptors.pb"), [])
+
+Benchee.run(
+  %{
+    "original": &Concentrate.Encoder.GTFSRealtimeHelpers.group/1,
+    "new": &Concentrate.Encoder.GTFSRealtimeHelpers.group_new/1
+    #"enum": fn -> Concentrate.Merge.merge(Enum.flat_map(data, &elem(&1, 1))) end,
+    ##"stream": fn -> Concentrate.Merge.merge(Stream.flat_map(data, &elem(&1, 1))) end,
+    #"flatten": fn -> Concentrate.Merge.merge(List.flatten(Map.values(data))) end,
+    #"new": fn -> Concentrate.Merge.merge_new(Enum.flat_map(data, &elem(&1, 1))) end
+    #"ets": fn -> Concentrate.Merge.merge_ets(data) end
+  },
+  inputs: %{data: data},
+  time: 10)
diff --git a/bench/map_reduce.exs b/bench/map_reduce.exs
new file mode 100644
index 00000000..9c9aa372
--- /dev/null
+++ b/bench/map_reduce.exs
@@ -0,0 +1,50 @@
+defmodule MapReduce do
+  def original(map) do
+    acc = {:cont, 0}
+    Enumerable.List.reduce(:maps.to_list(map), acc, &sum/2)
+  end
+
+  def maybe_iterator(map) when map_size(map) <= 131_072 do # 2 ** 9
+    original(map)
+  end
+  def maybe_iterator(map) do
+    iterator(map)
+  end
+
+  def iterator(map) do
+    acc = {:cont, 0}
+    iter = :maps.iterator(map)
+    reduce_iter(iter, acc, &sum/2)
+  end
+
+  defp reduce_iter(_iter, {:halt, acc}, _fun), do: {:halted, acc}
+  defp reduce_iter(iter, {:suspend, acc}, fun), do: {:suspended, acc, &reduce_iter(iter, &1, fun)}
+  defp reduce_iter(iter, {:cont, acc}, fun) do
+    case :maps.next(iter) do
+      {key, value, iter} ->
+        reduce_iter(iter, fun.({key, value}, acc), fun)
+      :none ->
+        {:done, acc}
+    end
+  end
+
+  defp sum(_, b), do: {:cont, b}
+end
+
+Benchee.run(
+  %{
+    original: &MapReduce.original/1,
+    maybe_iterator: &MapReduce.iterator/1,
+    iterator: &MapReduce.iterator/1,
+  },
+  warmup: 1,
+  memory_time: 2,
+  print: [fast_warning: false],
+  inputs: %{
+    small: Map.new(0..31, fn i -> {i, i} end),
+    medium: Map.new(0..1023, fn i -> {i, i} end),
+    large: Map.new(0..32_767, fn i -> {i, i} end),
+    one_thirty_two: Map.new(0..(div(1_048_576, 8) - 1), fn i -> {i, i} end),
+    xlarge: Map.new(0..1_048_575, fn i -> {i, i} end)
+  }
+)
diff --git a/bench/merge_mod.exs b/bench/merge_mod.exs
new file mode 100644
index 00000000..eddd31fd
--- /dev/null
+++ b/bench/merge_mod.exs
@@ -0,0 +1,26 @@
+alias Concentrate.{TripDescriptor, VehiclePosition, StopTimeUpdate}
+alias Concentrate.Merge.{Table, TableOrig}
+
+data = for file <- Path.wildcard("/tmp/*.pb") do
+  Concentrate.Parser.GTFSRealtime.parse(File.read!(file), [])
+end |> List.flatten
+sort_fn = fn x ->
+  case x do
+    %TripDescriptor{} -> 0
+    %VehiclePosition{} -> 1
+    %StopTimeUpdate{} -> 2
+    _ -> 4
+  end
+end
+
+Benchee.run(
+  %{
+    "original": fn -> TableOrig.new() |> TableOrig.add(:source) |> TableOrig.update(:source, data) |> TableOrig.items |> Enum.sort_by(&Concentrate.Mergeable.sort_key/1) end,
+    # "enum": fn -> Concentrate.Merge.merge(Enum.flat_map(data, &elem(&1, 1))) end,
+    # "stream": fn -> Concentrate.Merge.merge(Stream.flat_map(data, &elem(&1, 1))) end,
+    # "flatten": fn -> Concentrate.Merge.merge(List.flatten(Map.values(data))) end,
+    "new": fn -> Table.new() |> Table.add(:source) |> Table.update(:source, data) |> Table.items end
+    #proto": fn -> Concentrate.MergeProto.merge(data) end,
+    #"ets": fn -> Concentrate.Merge.merge_ets(data) end
+  },
+  time: 10)
diff --git a/bench/recent.exs b/bench/recent.exs
new file mode 100644
index 00000000..82f068b9
--- /dev/null
+++ b/bench/recent.exs
@@ -0,0 +1,33 @@
+defmodule BenchRecent do
+  @moduledoc false
+  @data Enum.to_list(0..1000)
+  @values (for key <- ~w(a b c b c a)a do
+    {key, @data}
+  end)
+
+  @selector {:_, :"$1"}
+
+  def map_flat(_) do
+    state = %{}
+  {[_ | _], _} = Enum.reduce(@values, {nil, state}, fn {key, value}, {_, acc} ->
+      acc = Map.put(acc, key, value)
+      {Enum.flat_map(acc, &elem(&1, 1)), acc}
+    end)
+  end
+
+  def ets(state) do
+    [_ | _] = Enum.reduce(@values, nil, fn {key, value}, _ ->
+      :ets.delete(state, key)
+      inserts = for v <- value, do: {key, v}
+      _ = :ets.insert(state, inserts)
+      :ets.match(state, @selector)
+    end)
+  end
+end
+
+Benchee.run(%{
+      "map_flat": &BenchRecent.map_flat/1,
+      "ets": &BenchRecent.ets/1,
+            },
+  before_each: fn input -> :ets.new(:tab, [:bag]) end
+)
diff --git a/bench/skipped_departures.exs b/bench/skipped_departures.exs
new file mode 100644
index 00000000..cd50b387
--- /dev/null
+++ b/bench/skipped_departures.exs
@@ -0,0 +1,30 @@
+alias Concentrate.{TripDescriptor, StopTimeUpdate}
+
+td = TripDescriptor.new([])
+five_skipped = for _ <- 0..4 do
+  StopTimeUpdate.new(schedule_relationship: :SKIPPED)
+end
+one_skipped = Enum.take(five_skipped, 1)
+ten_normal = for _ <- 0..9 do
+  StopTimeUpdate.new(departure_time: 5)
+end
+
+Benchee.run(
+  %{
+    "original": &Concentrate.GroupFilter.SkippedDepartures.filter/1,
+    "new": &Concentrate.GroupFilter.SkippedDeparturesNew.filter/1
+    #"enum": fn -> Concentrate.Merge.merge(Enum.flat_map(data, &elem(&1, 1))) end,
+    ##"stream": fn -> Concentrate.Merge.merge(Stream.flat_map(data, &elem(&1, 1))) end,
+    #"flatten": fn -> Concentrate.Merge.merge(List.flatten(Map.values(data))) end,
+    #"new": fn -> Concentrate.Merge.merge_new(Enum.flat_map(data, &elem(&1, 1))) end
+    #"ets": fn -> Concentrate.Merge.merge_ets(data) end
+  },
+  inputs: %{
+    no_skipped: {td, [], ten_normal},
+    one_skipped_end: {td, [], ten_normal ++ one_skipped},
+    one_skipped: {td, [], ten_normal ++ one_skipped ++ ten_normal},
+    five_skipped_end: {td, [], ten_normal ++ five_skipped},
+    five_skipped: {td, [], ten_normal ++ five_skipped ++ ten_normal}
+  },
+  print: [fast_warning: false],
+  time: 5)