Add benchmark for Quicksort

Author: tbagrel1

bench/Data/Mutable/Quicksort.hs

@@ -0,0 +1,52 @@
+{-# LANGUAGE NumericUnderscores #-}
+
+module Data.Mutable.Quicksort (benchmarks) where
+
+import Control.DeepSeq (force)
+import Control.Exception (evaluate)
+import Data.List (sort)
+import Simple.Quicksort (quickSort)
+import System.Random
+import Test.Tasty.Bench
+
+-- Follows thread from https://discourse.haskell.org/t/linear-haskell-quicksort-performance/10280
+
+qs :: (Ord a) => [a] -> [a]
+qs [] = []
+qs (x : xs) = qs ltx ++ x : qs gex
+  where
+    ltx = [y | y <- xs, y < x]
+    gex = [y | y <- xs, y >= x]
+
+linArrayQuicksort, lazyListQuicksort, stdLibSort :: [Int] -> [Int]
+linArrayQuicksort = quickSort
+lazyListQuicksort = qs
+stdLibSort = sort
+
+gen :: StdGen
+gen = mkStdGen 4541645642
+
+randomListBuilder :: Int -> IO [Int]
+randomListBuilder size = evaluate $ force $ take size (randoms gen :: [Int])
+
+sizes :: [Int]
+sizes = [1_000, 50_000, 1_000_000]
+
+benchmarks :: Benchmark
+benchmarks =
+  bgroup
+    "quicksort"
+    ( ( \size ->
+          env (randomListBuilder size) $ \randomList ->
+            bgroup
+              ("size " ++ (show size))
+              [ bench "linArrayQuicksort" $
+                  nf linArrayQuicksort randomList,
+                bench "lazyListQuicksort" $
+                  nf lazyListQuicksort randomList,
+                bench "stdLibSort" $
+                  nf stdLibSort randomList
+              ]
+      )
+        <$> sizes
+    )

bench/Main.hs

@@ -2,11 +2,13 @@ module Main where
 
 import qualified Data.Mutable.Array as Array
 import qualified Data.Mutable.HashMap as HashMap
+import qualified Data.Mutable.Quicksort as Quicksort
 import Test.Tasty.Bench (defaultMain)
 
 main :: IO ()
 main = do
   defaultMain
     [ Array.benchmarks,
-      HashMap.benchmarks
+      HashMap.benchmarks,
+      Quicksort.benchmarks
     ]

examples/Simple/Quicksort.hs

@@ -1,6 +1,10 @@
 {-# LANGUAGE LinearTypes #-}
 {-# LANGUAGE NoImplicitPrelude #-}
 
+-- Uncomment the line below to observe the generated (optimised) Core. It will
+-- land in a file named “Quicksort.dump-simpl”
+-- {-# OPTIONS_GHC -ddump-simpl -ddump-to-file -dsuppress-all -dsuppress-uniques #-}
+
 -- | This module implements quicksort with mutable arrays from linear-base
 module Simple.Quicksort where
 

linear-base.cabal

@@ -219,6 +219,7 @@ benchmark bench
     other-modules:
         Data.Mutable.HashMap
         Data.Mutable.Array
+        Data.Mutable.Quicksort
     default-language: Haskell2010
     build-depends:
         base,