[Haskell-cafe] FPS lib
Donald Bruce Stewart
dons at cse.unsw.edu.au
Tue Oct 18 20:43:02 EDT 2005
dons:
> 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?
(As I'd be willing to set up a nice benchmark script for all this code)
-- Don
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