[Haskell-cafe] Re: Waiting for thread to finish

[Dan Weston]

Silly or not, if I compile with -threaded, I always link in the 
one-liner C file:

   char *ghc_rts_opts = "-N2";

so I don't have to remember at runtime whether it should run with 2 
cores or not. This just changes the default to 2 cores, so I am still 
free to run on only one core with the runtime flags +RTS -N1, though I 
rarely need to.

http://www.haskell.org/ghc/docs/latest/html/users_guide/runtime-control.html#rts-hooks

Dan

Brad Clow wrote:
> Silly mistake. I had compiled with -threaded, but forgot the +RTS -N2.
> 
> However, I have a more complex app, where I haven't forgotton to use
> the right flags :-) and the utilisation of cores is very poor. I am
> thinking it is due to laziness. I am currently wondering how GHC
> handles the case where the function that is being forked uses lazy
> arguments?
> 
> On Nov 28, 2007 10:54 AM, Spencer Janssen <sjanssen at cse.unl.edu> wrote:
> 
>> Did you compile with -threaded, and run with +RTS -N2?
> 
> Regards
> brad
>