How long is your Template Haskell taking to run?

timestamp.hs

timestamp :: String -> Q a -> Q a
timestamp name action = do
  start <- runIO getCurrentTime
  runIO $ putStrLn $ "Starting " <> name <> ": " <> show start
  a <- action
  end <- runIO getCurrentTime
  runIO $ do
    putStrLn $ "Ending " <> name <> ": " <> show end
    putStrLn $ "Elapased " <> name <> ": " <> show (diffUTCTime end start)
  pure a
  
-- used like:

timestamp "persistent models" $ share [mkPersist persistSettings] 
  $(timestamp "persistent parsing" $ persistFileWith lowercaseSettings "file")