Re: Default options for -threaded

Oh, thanks! I wasn't aware of either or these! Useful to know. That does cover the use case I could think of. Thanks, Tamar On Mon, Oct 10, 2016, 14:34 Ben Gamari wrote:

Phyx writes:

...

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=...