[Haskell-beginners] Real World Haskell: Deprecated Libraries

[John Ky]

It looks like Haskell stack's profile options are defeating stream fusion.

Anyone know a work-around?


On Mon, 28 Nov 2016 at 08:23 John Ky <newhoggy at gmail.com> wrote:

> Hello Haskellers,
>
> I have been working through the Real World Haskell chapter on Profiling
> and Optimisation
> <http://book.realworldhaskell.org/read/profiling-and-optimization.html>,
> and got to the section *Advanced techniques: fusion*, where I encountered
> some code using Data.Array.Vector from the deprecated library uvector.
>
> Does anyone know how to rewrite this to not use deprecated libraries?
>
> I have tried to use Data.Vector.Unboxed from vector, but my version
> consumes a lot of memory.
>
> The code I have is here:
>
>
> https://github.com/haskell-works/hw-tutorial-performance/blob/master/hw-tutorial-performance-rwhe/Main.hs
>
> With that code, I get “1831 MB total memory in use”, which is terrible
>
> Build run steps I used were:
>
> stack build --executable-profiling --library-profiling --ghc-options="-fprof-auto -rtsopts -auto-all -caf-all -fforce-recomp"
>
> time /Users/jky/wrk/haskell-works/hw-tutorial-performance/.stack-work/install/x86_64-osx/lts-7.10/8.0.1/bin/hw-tutorial-performance-rwhe +RTS -sstderr -p -hy -RTS 1e7
>
> I get very large numbers of allocations of Pair and Double.
>
> There is also a very large upfront allocation ARR_WORDS, which I feared
> would happen when using Data.Vector
>
> Any help appreciated.
>
> Cheers,
>
> -John
> ​
>
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