Re: [Haskell-cafe] Haskell Speed Myth

On 23 Aug 2008, at 20:01, Luke Palmer wrote:

2008/8/23 Thomas Davie :

...

Finally, that threading example... WOW! 65 times faster, and the code is *really* simple. The C on the other hand is a massive mess.

I've been wondering about this, but I can't check because I don't have a multi core cpu. I've heard GHC's single threaded runtime is very very good. What are the results for the threading example when compiled with -threaded and run with at least +RTS -N2?

That's really interesting -- I just tried this. Compiling not using -threaded: 1.289 seconds Compiling using -threaded, but not running with -N2: 3.403 seconds Compiling using -threaded, and using -N2: 55.072 seconds Wow! Haskell's runtime really is a *lot* better than trying to use operating system threads. I wonder if there's a point at which it becomes better to use both CPUs, or if the overhead of using OS threads for that problem is just too high. Bob