[Haskell] Comments from Brent Fulgham on Haskell and the shootout

Tue Jun 27 05:44:45 EDT 2006

Brent Fulgham has given me permission to share this message that he sent
to us about his views on Haskell and the Great Computer Language
Shootout. There's some nice advocacy material in here.
I'd like to publicly thank Brent for all his work on the shootout -
benchmarking 50 or so different language implementations and getting any
kind of useful results at all is a significant feat. The shootout
results have also influenced our direction in the Haskell community and
GHC in particular.
Here's the message, for your enjoyment...
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Dear Drs. Hudak and Peyton-Jones:
(Feel free to forward these comments to anyone you think would enjoy 
them).
A couple of years ago I revived the dormant "Great Computer Language 
Shootout" website because I wanted to create an up-to-date comparison 
of language implementations to use as ammunition against my nay- 
saying coworkers over the state of the art in Computer Science. Back 
in those days, I was mainly interested in the performance of 
Objective Caml and Lisp, but was also interested in a new (to me) 
language called Haskell .
Haskell had (and still has) a beautiful, mathematical notation that 
was very easy to read, but it was such a poor performer that I 
despaired of ever getting to use it for anything but simple test 
programs. While it was conceptually satisfying, pragmatism seemed 
destined to keep it on the shelf for the foreseeable future.
I wanted to write to inform you how shocked I was to see the great 
advances in performance in the Glorious Haskell Compiler over the 
last year or so. Of course, we have also benefited from some great 
contributions by the folks on the Haskell-Cafe mailing list.
The thing I find most staggering about the compiler is that its quite 
brilliant at identifying wasted work. Many of the original shootout 
test cases were written to test the performance of simple scripting 
languages, and had grown a set of hacks over the years to keep the 
run times large enough to measure as processor speeds improved and 
language implementations became more sophisticated. In many cases, 
tests involved calculation or large values in loops, which would 
cause Perl and Python (and even C, Java, and C++) to chug merrily 
away burning cycles so that I could measure the timings in seconds, 
rather than microseconds.
Then along came GHC, which began achieving enormous wins over the 
other languages because the lazy nature of the evaluation threw out 
the unneeded calculations, handing over the final useful result 
without breaking a sweat. Consequently, we had to revise many of the 
tests to force the programs to perform real work that could not be 
avoided, in some cases by forcing intermediate values to be printed 
in the solutions so we could be sure the work was actually being 
done. With those changes, Haskell began to fall back in speed to 
more moderate levels.
However, in the last few releases of GHC (and the last several rounds 
of tweaks by the Haskellers on the Cafe list), GHC has risen to the 
top of the heap, approaching native C in performance overall. What I 
find quite appealing about this is that the performance is consistent 
across platforms. While Java's "HotSpot" compiler makes a good 
showing on Intel, my AMD test machine yields consistently worse 
results than the Pentium IV system. However, GHC performs equally 
well on both systems, yielding a similar fractional performance 
against C in both cases[1,2].
I think this is great because it means that applications written in 
Haskell can be reasonably expected to yield good performance on all 
of the common x86 platforms without customizations. Java and several 
other languages seem to yield varying performance, probably because 
of advanced optimizations available on the Intel platform that have 
been hand-coded into those systems.
At any rate, I just wanted to write a quick fan letter about Haskell, 
and let you know how impressed I am with its performance. Looks like 
it's time for me to start taking a serious look at Haskell for some 
real-world problems at work now!
Best regards,
Brent Fulgham
http://shootout.alioth.debian.org/
[1] "http://shootout.alioth.debian.org/gp4/benchmark.php? 
test=all&lang=all"
[2] "http://shootout.alioth.debian.org/debian/benchmark.php? 
test=all&lang=all"
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