naive benchmarks, rustc vs ghc

results.txt

$ ghc -O Test.hs && ./Test 
Sequence.|> [65536 * 5000] took 7.943 ms
$ rustc -O test.rs && ./test
VecDeque::extend [65536 * 5000] took 619.233631ms

Test.hs

import qualified Data.Sequence as S
import qualified Data.ByteString as BS

import Control.DeepSeq
import Data.Foldable
import Data.Traversable
import Data.IORef
import Data.Word
import GHC.Clock
import System.IO

main :: IO ()
main = do
  null <- openFile "/dev/shm/tmphs1234567890" WriteMode
  d <- newIORef 0
  for [1..5000] $ \_ -> do
    let bs = BS.replicate 65536 0
    hPrint null $ bs `deepseq` BS.foldl' (+) 0 bs -- force evaluation
    let q = S.Empty :: S.Seq Word8
    hPrint null $ q -- force evaluation
    l <- getMonotonicTimeNSec
    let q2 = BS.foldl' (S.|>) q bs
    hPrint null $ q2 `deepseq` sum q2 -- force evaluation
    e <- getMonotonicTimeNSec
    modifyIORef' d (+ (e - l))
  d <- readIORef d
  putStrLn $ "Sequence.|> [65536 * 5000] took " <> show (fromIntegral d / 1000000.0) <> " ms"

test.rs

use std::collections::VecDeque;
use std::time::{Duration, Instant};

pub fn main() {
  let mut d = Duration::from_millis(0);
  for _ in 1..=5000 {
    let buf = [0; 65536];
    let mut queue: VecDeque<u8> = VecDeque::with_capacity(65536);
    let l = Instant::now();
    queue.extend(buf.iter());
    d += l.elapsed();
  }
  println!("VecDeque::extend [65536 * 5000] took {:?}", d);
}