Re[2]: [Haskell-cafe] Automatic parallelism in Haskell, similar to "make -j4"?

Hello T, Monday, November 3, 2008, 3:42:49 AM, you wrote:

On Sun, Nov 2, 2008 at 6:44 PM, Bulat Ziganshin wrote:

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What would it take to implement a -j equivalent for, say, GHC? Or if this is not possible, what is wrong with my reasoning?

problem is that make have rather large pices of work which it can run parallel. if ghc will try to parallel every machine operation, it will pend more time maintaining these jobs. 'par' is just the way to tell GHC "this part of job is large enough"

Right, but couldn't the Haskell complier+runtime discover "rather large pieces of work"?

are you ever herd about "halting problem"? it's imposible in general case and i doubt how far it may be done on practice. in general, it looks close to really compute the function (and you still need to know its actual input params!) anyway it's not done and i don't heard about researches in this direction -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com