Generate profiling reports

.dialyzer_ignore

@@ -0,0 +1,4 @@
+Unknown functions:
+  fprof:analyse/1
+  fprof:apply/3
+  fprof:profile/1

.gitignore

@@ -21,3 +21,6 @@ erl_crash.dump
 
 # Emacs backup files
 *~
+
+# Profiling output directory
+/profile

lib/backtrex.ex

@@ -82,8 +82,10 @@ defmodule Backtrex do
     quote location: :keep do
       @behaviour Backtrex
 
-      def solve(problem) do
-        Backtrex.solve(__MODULE__, problem)
+      def solve(problem, backtracker \\ :naive_sequential) do
+        case backtracker do
+          :naive_sequential -> Backtrex.solve(__MODULE__, problem)
+        end
       end
     end
   end

lib/backtrex/profiler.ex

@@ -0,0 +1,91 @@
+defmodule Backtrex.Profiler do
+  alias Backtrex.Examples.Sudoku
+
+  @spec backends() :: [atom()]
+  def backends do
+    [
+      :naive_sequential,
+    ]
+  end
+
+  @spec problems() :: [{module(), [{atom(), any()}]}]
+  def problems do
+    [
+      {Sudoku.Solver,
+       [
+         quick_puzzle: example_puzzle()
+       ]},
+    ]
+  end
+
+  def combos do
+    for backend <- backends(),
+        {frontend, inputs} <- problems() do
+      for input <- inputs, do: {backend, frontend, input}
+    end
+    |> Enum.concat()
+  end
+
+  def combo_name({b, f, {n, _}}) do
+    "#{inspect b}-#{inspect f}-#{inspect n}"
+    |> String.replace(":", "")
+  end
+
+  def profile(dir \\ "./profile") do
+    if !File.exists?(dir) do
+      File.mkdir_p!(dir)
+    end
+
+    eflame(dir)
+    fprof(dir)
+  end
+
+  def eflame(dir) do
+    combos()
+    |> Enum.each(fn combo ->
+      fname = Path.join(dir, "stacks-#{combo_name(combo)}.out")
+      :eflame.apply(:normal_with_children, fname, __MODULE__, :run_test, [combo])
+      System.cmd("bash", ["./script/make_flamegraph.sh", fname])
+    end)
+  end
+
+  def fprof(dir) do
+    combos()
+    |> Enum.each(fn combo ->
+      trace_file = Path.join(dir, "fprof-#{combo_name(combo)}.trace") |> to_charlist
+      analysis_file = Path.join(dir, "fprof-#{combo_name(combo)}.analysis") |> to_charlist
+      :fprof.apply(&run_test/1, [combo], [
+                     {:file, trace_file}
+                   ])
+      :fprof.profile(file: trace_file)
+      :fprof.analyse([
+        dest: analysis_file,
+        callers: true,
+        sort: :own,
+        totals: true,
+        details: true])
+    end)
+  end
+
+  def example_puzzle do
+    {:ok, puzzle} = Sudoku.Puzzle.from_list([
+      [5,   3, :_, :_,  7, :_, :_,  1,  2],
+      [6,   7, :_,  1,  9,  5, :_,  4, :_],
+      [1,   9,  8,  3, :_, :_,  5,  6,  7],
+      [8,  :_,  9, :_,  6, :_,  4, :_,  3],
+      [4,   2, :_,  8, :_,  3,  7, :_,  1],
+      [7,  :_,  3, :_,  2,  4, :_,  5,  6],
+      [:_,  6, :_,  5, :_,  7,  2,  8, :_],
+      [2,  :_, :_,  4,  1,  9,  6, :_,  5],
+      [:_,  4,  5, :_,  8,  6, :_,  7,  9]])
+    puzzle
+  end
+
+  def run_test({backend, frontend, {_name, input}}) do
+    {:ok, :solution, _} = apply(frontend, :solve, [input, backend])
+  end
+
+  def run_test do
+    example_puzzle() |> Backtrex.Examples.Sudoku.Solver.solve
+  end
+end

lib/mix/tasks/backtrex/profile.ex

@@ -0,0 +1,10 @@
+defmodule Mix.Tasks.Backtrex.Profile do
+  use Mix.Task
+
+  @shortdoc "Run Backtrex profiler."
+  def run(_) do
+    output_dir = "profile"
+    Backtrex.Profiler.profile(output_dir)
+    IO.puts "Profiler data written to #{output_dir}."
+  end
+end

mix.exs

@@ -10,18 +10,21 @@ defmodule Backtrex.Mixfile do
      elixirc_options: [warnings_as_errors: true],
      description: description(),
      package: package(),
-     deps: deps()]
+     deps: deps(),
+     dialyzer: [ignore_warnings: ".dialyzer_ignore"],
+    ]
   end
 
   def application do
-    [extra_applications: [:logger],
+    [extra_applications: [:logger, :eflame, :mix],
      applications: [:logger]]   # format expected by Elixir 1.3
   end
 
   defp deps do
     [
       {:credo, "~> 0.5", only: [:dev, :test]},
       {:dialyxir, "~> 0.4", only: [:dev], runtime: false},
+      {:eflame, ~r/.*/, git: "https://github.com/proger/eflame.git", compile: "rebar compile"},
       {:ex_doc, "~> 0.14", only: :dev},
     ]
   end

mix.lock

@@ -2,6 +2,7 @@
   "credo": {:hex, :credo, "0.5.3", "0c405b36e7651245a8ed63c09e2d52c2e2b89b6d02b1570c4d611e0fcbecf4a2", [:mix], [{:bunt, "~> 0.1.6", [hex: :bunt, optional: false]}]},
   "dialyxir": {:hex, :dialyxir, "0.4.3", "a4daeebd0107de10d3bbae2ccb6b8905e69544db1ed5fe9148ad27cd4cb2c0cd", [:mix], []},
   "earmark": {:hex, :earmark, "1.0.3", "89bdbaf2aca8bbb5c97d8b3b55c5dd0cff517ecc78d417e87f1d0982e514557b", [:mix], []},
+  "eflame": {:git, "https://github.com/proger/eflame.git", "ee3a44b950aeb2434460045274809ad506141a83", []},
   "ex_doc": {:hex, :ex_doc, "0.14.5", "c0433c8117e948404d93ca69411dd575ec6be39b47802e81ca8d91017a0cf83c", [:mix], [{:earmark, "~> 1.0", [hex: :earmark, optional: false]}]},
   "inch_ex": {:hex, :inch_ex, "0.5.5", "b63f57e281467bd3456461525fdbc9e158c8edbe603da6e3e4671befde796a3d", [:mix], [{:poison, "~> 1.5 or ~> 2.0 or ~> 3.0", [hex: :poison, optional: false]}]},
   "poison": {:hex, :poison, "3.0.0", "625ebd64d33ae2e65201c2c14d6c85c27cc8b68f2d0dd37828fde9c6920dd131", [:mix], []}}

script/make_flamegraph.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# Makes a flame graph from :eflame's output. Could eventually be converted to
+# Elixir, but would require I/O redirection.
+
+STACK_TO_FLAME="./deps/eflame/stack_to_flame.sh"
+STACK_FILE="$1"
+SVG_OUT_FILE="${STACK_FILE/%.out/.svg}"
+
+"$STACK_TO_FLAME" < "$STACK_FILE" > "$SVG_OUT_FILE"