CODEWITHSUNDEEP
haskelltimeprofilingexecutionmeasurement
user645466
user645466

Reputation:

How to get a program's running time in Haskell

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.

Upvotes: 14

Views: 10393

Answers (4)

Zane XY
Zane XY

Reputation: 2809

:set +s is really neat if use ghci, otherwise you can use Criterion.Measurement, see my answer to another question with example.

Upvotes: 6

Dan Burton
Dan Burton

Reputation: 53715

I'm not sure how accurate it is, but using :set +s in ghci will show the time and space used for subsequent computations.

Upvotes: 4

Don Stewart
Don Stewart

Reputation: 137997

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:

For more statistically sound measurement, consider

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?

Upvotes: 12

Thomas M. DuBuisson
Thomas M. DuBuisson

Reputation: 64750

1) If you want to benchmark something, use the criterion package.

2) If you want to time a function and are positive you have controlled for laziness as needed, then just use Data.Time.getCurrentTime from the time package.:

import Data.Time
...
   start <- getCurrentTime
   runOperation
   stop <- getCurrentTime
   print $ diffUTCTime stop start

A slicker packaging of the above pattern can be found in the timeit package.

3) If you actually want the running time of a program that just happens to be written in Haskell then use your systems time utility. For most POSIX systems (Mac, Linux) just run:

$ time ./SomeProgram

And it will report user, wall, and system time.

Upvotes: 24

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