Re: [Haskell-cafe] Foreign function performance: monadic vs pure

On Mon, Apr 11, 2011 at 3:55 PM, Serguei Son wrote:

So if I must use a safe function returning IO a, there is no way to improve its performance? To give you a benchmark, calling gsl_ran_ugaussian a million times in pure C takes only a second or two on my system.

In the C version, are you also producing a linked list containing all of the values? Because that's what mapM does. Your test is mostly measuring the cost of allocating and filling ~3 million machine words on the heap. Try mapM_ instead. G -- Gregory Collins