Phyx
Oops, sorry, only just now seen this. It seems my overly aggressive filters couldn't decide where to put the email :)
I do agree to some extend with this. I'd prefer if I made a mistake for my system not to hang. The one downside to this default though is that you can't just hand a program over to user and have it run at full capabilities.
If it possible to set this from inside a program? My guess is no, since by the time you get to main the rts is already initialized?
Would a useful alternative be to provide a compile flag that would change the default? e.g. opt-in? Since now there is a small burden on the end user.
There exist two pretty good tools for accomplishing what you want, 1. Call Control.Concurrent.setNumCapabilities [1] from within your application. 2. Use GHC's -with-rtsopts flag [2] to set the default RTS arguments during compilation of your application. Cheers, - Ben [1] http://localhost:7000/file/opt/exp/ghc/roots/8.0.1/share/doc/ghc-8.0.1/html/... [2] http://downloads.haskell.org/~ghc/master/users-guide//phases.html?highlight=...