Import the parallel package as follows:

import Control.Parallel.Strategies (runEval, rpar)

Evaluate two tasks in parallel, and wait for both tasks to finish before returning as seen in the following code snippet:

main = do
  print $ runEval $ do
    a <- rpar task1
    b <- rpar task2
    return (a, b)

A time-consuming task can be created as follows:

task1 = 8^8^9 :: Integer

Another time-consuming task can be created as follows:

task2 = 8^8^8 :: Integer

Compile the code with the threaded and rtsopts flags enabled, as follows:

$ ghc -O2 --make Main.hs -threaded –rtsopts

Run it by specifying...