I have a set of binary records packed into a file and I am reading them using Data.ByteString.Lazy and Data.Binary.Get. With my current implementation an 8Mb file takes 6 seconds to parse.

import qualified Data.ByteString.Lazy as BL
import Data.Binary.Get

data Trade = Trade { timestamp :: Int, price :: Int ,  qty :: Int } deriving (Show)

getTrades = do
  empty <- isEmpty
  if empty
    then return []
    else do
      timestamp <- getWord32le          
      price <- getWord32le
      qty <- getWord16le          
      rest <- getTrades
      let trade = Trade (fromIntegral timestamp) (fromIntegral price) (fromIntegral qty)
      return (trade : rest)

main :: IO()
main = do
  input <- BL.readFile "trades.bin" 
  let trades = runGet getTrades input
  print $ length trades

What can I do to make this faster?

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