[Haskell-cafe] Re: Efficient signal processing

Henning Thielemann lemming at henning-thielemann.de
Mon Jun 18 07:34:55 EDT 2007

On Sun, 17 Jun 2007, Donald Bruce Stewart wrote:

> simonmarhaskell:
> > Henning Thielemann wrote:
> >
> > >The program is compiled with GHC-6.4 and option -O2, CPU clock 1.7 GHz.
> >
> > ByteString is much faster with GHC 6.6, IIRC.  We optimised the
> > representation of ForeignPtr, and ByteString takes advantage of that.  I
> > recommend upgrading.
> Yes, a 2x speedup isn't uncommon.

Indeed, in my simple example the speedup factor was 2. However this is
still far from being enough for real-time signal processing. I found
another problem: The rounding functions from RealFrac are much slower than
GHC.Float.double2Int. I've set up a bug ticket in GHC trac.

> ByteString is even faster with the GHC head, branch, given the cranked
> up rules and constructor specialisation.

Can I test them without compiling GHC myself? I.e. can I still install the
FPS package separately?

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