文字列連結ベンチ

{-# LANGUAGE OverloadedStrings #-}                                                   

import Data.Monoid                                                                   
import Blaze.ByteString.Builder as B                                                 
import Blaze.ByteString.Builder.Char.Utf8 as BT                                      
import qualified Data.ByteString.Char8 as BS                                         
import qualified Data.Text as T                                                      
import qualified Data.Text.Encoding as T                                             
import Criterion.Main                                                                

concatBT :: [T.Text] -> T.Text
concatBT = T.decodeUtf8 . B.toByteString . mconcat . map BT.fromText                 

concatBB :: [BS.ByteString] -> BS.ByteString                                         
concatBB = B.toByteString . mconcat . map B.fromByteString                           

main :: IO ()                                                                        
main = defaultMain                                                                   
  [ bench "String"       $ nf   concat   $ replicate 1000 ("hello" :: String)        
  , bench "blaze (Text)" $ whnf concatBT $ replicate 1000 ("hello" :: T.Text)        
  , bench "blaze (BS)"   $ whnf concatBB $ replicate 1000 ("hello" :: BS.ByteString)
  ]                                                                                  

結果：

warming up
estimating clock resolution...
mean is 1.427688 us (640001 iterations)
found 6395 outliers among 639999 samples (1.0%)
  6056 (0.9%) high severe
estimating cost of a clock call...
mean is 37.01206 ns (12 iterations)
found 1 outliers among 12 samples (8.3%)
  1 (8.3%) high mild

benchmarking String
mean: 71.54872 us, lb 71.11242 us, ub 72.54105 us, ci 0.950
std dev: 3.221645 us, lb 1.745424 us, ub 6.485196 us, ci 0.950
found 5 outliers among 100 samples (5.0%)
  3 (3.0%) high mild
  2 (2.0%) high severe
variance introduced by outliers: 42.508%
variance is moderately inflated by outliers

benchmarking blaze (Text)
mean: 93.39355 us, lb 92.54418 us, ub 94.62662 us, ci 0.950
std dev: 5.182060 us, lb 3.906787 us, ub 7.223113 us, ci 0.950
found 7 outliers among 100 samples (7.0%)
  4 (4.0%) high mild
  3 (3.0%) high severe
variance introduced by outliers: 53.465%
variance is severely inflated by outliers

benchmarking blaze (BS)
mean: 25.15464 us, lb 24.74210 us, ub 26.21941 us, ci 0.950
std dev: 3.155812 us, lb 1.518559 us, ub 6.576698 us, ci 0.950
found 12 outliers among 100 samples (12.0%)
  3 (3.0%) high mild
  9 (9.0%) high severe
variance introduced by outliers: 86.249%
variance is severely inflated by outliers