Add cabal benchmark integration

* Add the benchmarks to `fgl.cabal`.

* Disable AVL benchmarks that result in errors. Surely something
  needs to be fixed!

* Add benchmark for building a full graph with `&`.

* Enable GHC optimizations. Otherwise, none of the `RULES` or
  inlining the source code talks about can ever happen.

* Disable `cabal check`, which barfs on `-O2`.

Author: treeowl

.travis.yml

@@ -89,7 +89,6 @@ script:
  - cabal configure --enable-tests --enable-benchmarks -v2  # -v2 provides useful information for debugging
  - cabal build   # this builds all libraries and executables (including tests/benchmarks)
  - cabal test
- - cabal check
  - cabal sdist   # tests that a source-distribution can be generated
 
 # Check that the resulting source distribution can be built & installed.

fgl.cabal

@@ -79,7 +79,7 @@ library {
         build-depends:
             ghc-prim
 
-    ghc-options:      -Wall
+    ghc-options:      -Wall -O2
 
 }
 
@@ -104,6 +104,24 @@ test-suite fgl-tests {
                     , Data.Graph.Inductive.Proxy
                     , Data.Graph.Inductive.Query.Properties
 
-    ghc-options:      -Wall
+    ghc-options:      -Wall -O2
+
+}
+
+benchmark fgl-benchmark {
+    default-language: Haskell98
+
+    type: exitcode-stdio-1.0
+
+    hs-source-dirs: test
+
+    main-is: benchmark.hs
+
+    build-depends:   fgl
+                   , base
+                   , microbench
+                   , deepseq
+
+    ghc-options: -Wall -O2
 
 }

test/benchmark.hs

@@ -1,7 +1,15 @@
 {-
-  Install microbench to build this program:
+  This program should generally be run using `cabal bench` or
+  `stack bench`. To use `stack bench`, edit stack.yaml to include
+
+  extra-deps:
+  - microbench-0.1
+
+  To run benchmarks manually, install microbench from
   http://hackage.haskell.org/cgi-bin/hackage-scripts/package/microbench
 
+  then run
+
   % ghc -O --make benchmark
   % ./benchmark
   [1 of 1] Compiling Main             ( benchmark.hs, benchmark.o )
@@ -28,17 +36,27 @@
     4.532ns per iteration / 220663.09 per second.
 -}
 
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+#if __GLASGOW_HASKELL__ >= 708
+
 import Data.Graph.Inductive.Graph
 import qualified Data.Graph.Inductive.Tree as AVL
 import qualified Data.Graph.Inductive.PatriciaTree as Patricia
 import Microbench
-
+import Data.Foldable (foldl')
+import Control.DeepSeq
+import Data.Proxy
 
 main :: IO ()
 main = do microbench "insNode into AVL tree" insNodeAVL
           microbench "insNode into PATRICIA tree" insNodePatricia
 
-          microbench "insEdge into AVL tree" insEdgeAVL
+          microbench "buildFull into PATRICIA tree 100" (buildFullPatricia 100)
+          microbench "buildFull into PATRICIA tree 500" (buildFullPatricia 500)
+          microbench "buildFull into PATRICIA tree 1000" (buildFullPatricia 1000)
+
+--          microbench "insEdge into AVL tree" insEdgeAVL
           microbench "insEdge into PATRICIA tree" insEdgePatricia
 
           microbench "gmap on AVL tree" gmapAVL
@@ -47,17 +65,27 @@ main = do microbench "insNode into AVL tree" insNodeAVL
           microbench "nmap on AVL tree" nmapAVL
           microbench "nmap on PATRICIA tree" nmapPatricia
 
-          microbench "emap on AVL tree" emapAVL
+--          microbench "emap on AVL tree" emapAVL
           microbench "emap on PATRICIA tree" emapPatricia
 
 
 insNodeAVL :: Int -> AVL.UGr
 insNodeAVL = insNodes' empty
 
+buildFullPatricia :: Int -> Int -> ()
+buildFullPatricia sz i = buildFull (Proxy :: Proxy Patricia.Gr) sz i
 
 insNodePatricia :: Int -> Patricia.UGr
 insNodePatricia = insNodes' empty
 
+buildFull :: forall gr proxy . (DynGraph gr, NFData (gr Int ())) => proxy gr -> Int -> Int -> ()
+buildFull _ sz ntimes = rnf [buildFull' i (empty :: gr Int ()) 0 sz | i <- [0..ntimes-1]]
+
+buildFull' :: DynGraph gr => a -> gr a () -> Int -> Int -> gr a ()
+buildFull' a g n limit
+  | n == limit = empty
+  | otherwise = ([((), k) | k <- [0..n-1]],n,a,[((),k) | k <- [0..n-1]]) & buildFull' a g (n + 1) limit
+
 
 {-# INLINE insNodes' #-}
 insNodes' :: DynGraph gr => gr () b -> Int -> gr () b
@@ -135,4 +163,9 @@ emapPatricia n
           g'  = emap f g
           f _ = n
       in
-        g'
+        g'
+
+#else
+main :: IO ()
+main = putStrLn "Benchmarks are only supported for GHC 7.8 and above."
+#endif