[Haskell-cafe] FPS lib

[Donald Bruce Stewart]

john:
> On Wed, Oct 19, 2005 at 10:07:37AM +1000, Donald Bruce Stewart wrote:
> > kr.angelov:
> > > Hello Guys,
> > > 
> > > I tried my own version of PackedStrings and the results are very nice.
> > > It is entirely based on ByteArray# and Int#. I have made two tests:
> > > 
> > > Elapsed time
> > > |     | FastPackedString | PackedString |
> > > +-----+------------------+--------------+
> > > |test1|           99.26s |        3.81s |
> > > |test2|          175.88s |        5.28s |
> > >
> > > Maximum Memory Residency
> > > |     | FastPackedString | PackedString |
> > > +-----+------------------+--------------+
> > > |test1|          40.60Mb |      36.25Mb |
> > > |test2|          91.58Mb |      33.94Mb |
> > 
> > Wow. Now this is really surprising. 
> > 
> > Firstly, I would point out that only testing pack and concat may be
> > slightly unrepresentative :)
> > 
> > However, on my machine:
> > 
> >     OpenBSD/Pentium-M 1.6G/ghc-6.5 -O
> >     Elapsed time:        FPS          Simon's PackedString   Krasimir's
> >     test1                1.966s (40M)      2.151s (36M)      2.235s (36M)
> >     test2                6.048s (24M)      3.160s (73M)      2.318s (39M)
> > 
> > Which is basically what I expected. Though perhaps I need to improve
> > concat (we currently do things a little strangely in concat, due to the
> > darcs legacy), but pack itself is nice and fast.
> > 
> >     Linux/Pentium 4 3.6G/ghc-6.4.1 -O
> >     test1               35.37s            30.97s             2.180s
> >     test2               90.93s            60.55s             1.916s
> > 
> > Ah!! So what's going on on Linux, I wonder. Could it be something about
> > 6.4.1? Are we seeing the difference between ForeignPtrs from 6.4 to 6.5?
> > I will investigate.
> > 
> > I'd be very wary of switching entirely to non-portable ghc primop-based
> > code, as FPS already run ons hugs and I think nhc.
> 
> can we add Data.PackedString and my PackedString (in the jhc repo) to
> the testing lineup?
> 
> actually, is the test code available somewhere?

Ok, so we have:
    FPS is at                           http://www.cse.unsw.edu.au/~dons/fps.html
    SimonM's code I've posted at:       http://www.cse.unsw.edu.au/~dons/packedstring.tar.gz
    Data.PackedString in the base hier libs
    Krasimir's primop code posted online.
    John's code in the jhc repo (where?)

And also, potentially, is the FastString.hs code in ghc's utils/ dir.

I'm not sure if just testing pack and concat are very useful though.
Pack, at least, is rarely used in the way we're testing it -- generally
you avoid having Strings in the first place. 

There's some other tests in Simon's code, and a full regress suite in
FPS, using some large data sets.

What are we trying to establish here? 

-- Don