How to get a program's running time in Haskell

Question

How can I go about getting a program's running time through system time functions in Haskell? I would like to measure the execution time of a whole program and/or an individual function.

Answer 1

Assuming you don't just want to measure the total running time of your program, like so:

 $ time ./A

Then you can time a computation a number of ways in Haskell:

• Basic timing (e.g. as in the timeit package)
• Timing in cycles

For more statistically sound measurement, consider

• The Criterion package.

Finally, in all cases, you need to think about lazy evaluation: do you want to measure the cost of fully evaluating whatever data you produce, or just to its outermost constructor?