haskell zipwith vs. map-zip

output

warming up
estimating clock resolution...
mean is 1.363583 us (640001 iterations)
found 3371 outliers among 639999 samples (0.5%)
  2926 (0.5%) high severe
estimating cost of a clock call...
mean is 38.34752 ns (12 iterations)
found 1 outliers among 12 samples (8.3%)
  1 (8.3%) low severe

benchmarking zip test/map
collecting 100 samples, 1 iterations each, in estimated 288.3517 s
mean: 56.73412 ms, lb 56.40832 ms, ub 57.35469 ms, ci 0.950
std dev: 2.227947 ms, lb 1.426694 ms, ub 4.053248 ms, ci 0.950
found 3 outliers among 100 samples (3.0%)
  2 (2.0%) high severe
variance introduced by outliers: 36.537%
variance is moderately inflated by outliers

benchmarking zip test/zip
mean: 28.02551 ms, lb 27.90591 ms, ub 28.28736 ms, ci 0.950
std dev: 862.9143 us, lb 390.6073 us, ub 1.472298 ms, ci 0.950
found 16 outliers among 100 samples (16.0%)
  3 (3.0%) high mild
  13 (13.0%) high severe
variance introduced by outliers: 25.799%
variance is moderately inflated by outliers

rand.hs

import Criterion.Config
import Criterion.Main
import System.Random

main :: IO ()
main = newStdGen >>= defaultMainWith benchConfig (return ()) . benchmarks

randNumbers :: RandomGen g => g -> Int -> [Int]
randNumbers gen n = take n $ randoms gen

zipWithVals :: [Int] -> [Int] -> [Int]
zipWithVals  xs xs' = zipWith (*) xs xs'

mapZipVals :: [Int] -> [Int] -> [Int]
mapZipVals xs xs' = map (\(x,y) -> x * y) $ zip xs xs'

benchmarks :: RandomGen g => g -> [Benchmark]
benchmarks gen =
    let x1 = randNumbers gen n
        x2 = randNumbers gen n
        n = 1000000
    in [
      bgroup "zip test"
      [
        bench "map"  $ nf (mapZipVals  x1) x2
      , bench "zip"  $ nf (zipWithVals x1) x2
      ]
    ]

benchConfig :: Config
benchConfig = defaultConfig {
             cfgPerformGC = ljust True
           }