chrisdone:

On 4 June 2010 00:05, Don Stewart wrote:

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wasserman.louis:

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What, if anything, stands in the way of parallelizing Cabal installs, make -j style?

Parallelizing ghc --make

   http://vimeo.com/6572966

Unless Louis meant what's stopping cabal-install from installing dependancies in parallel instead of serial? In which case; nothing?

Oh, sorry, dependencies (package level parallelism) vs modules (ghc --make level parallelism) -- don

Excerpts from Christopher Done's message of Fri Jun 04 00:39:23 +0200 2010:

On 4 June 2010 00:05, Don Stewart wrote:

...

wasserman.louis:

...

What, if anything, stands in the way of parallelizing Cabal installs, make -j style?

Parallelizing ghc --make

   http://vimeo.com/6572966

Unless Louis meant what's stopping cabal-install from installing dependancies in parallel instead of serial? In which case; nothing?

I think cabal-install compiles Setup without starting ghc or such (I may be wrong). This would be fixable. If you want to volunteer try hack-nix. It's based on the Nix distribution system which provides this feature natively. You can even ask others computers to help building dependencies quite easily. Downside: At the moment it will pull all depndencies (including kernel headers and glibc..) if you install it on a common linux system. Marc Weber

Hmmm. Now that I've had a chance to rewatch the video, I am enlightened. Nevertheless, I will confess that I wouldn't mind the idea of just doing an external parallelism wrapper, running multiple sessions of GHC rather than making GHC internally parallel. Hrrrrm. Louis Wasserman wasserman.louis@gmail.com http://profiles.google.com/wasserman.louis On Thu, Jun 3, 2010 at 11:57 PM, Evan Laforge wrote:

Something I wondered from watching that talk, rather than trying to make ghc run concurrently internally, can we just have --make, when faced with multiple possibilities, pick the first one without a 'ModuleName.working' file, create such a working file, and then go to?

Then you can run 'ghc --make X.hs &; ghc --make X.hs &; ...'.

In fact, isn't that what make -j already does? I could try it with the old style 'ghc -M' and pure makefile, but it turns out to be a lot of work to figure out what packages to include and tangle out the right .o files and whatnot, work that --make does for me.