I said nothing about fairness, and *never at any point said I thought Don's results were more useful or fair.* What makes you think that's what I meant to imply? You have not responded to my separate concern that
For code that actively requires computation at runtime, I have seen no examples of an instance where well-optimized GHC is actually dozens or hundreds of times slower than GCC output.
Rather than accusing me of taking sides, if you'd take an actual
apples-to-apples comparison, citing the best Haskell results and best GCC
results -- without using examples from either language which performed
computation at compile-time that would not be possible in everyday programs
-- my original claims were true: that GHC code is frequently within 3x the
speed of GCC code, and hacked-up GHC code can reach and match GCC
performance -- though I agree those hacks require an impractical blowup in
code size. (Depending on your individual interpretation of what an average
Haskell program looks like, I concede that 3x might be off by a factor of 2
or so -- but not the factor of 50 you claimed.)
Don's "-D64" results, while *not* a useful gcc-vs-ghc comparison, are
relevant if really determined Haskellers are interested in learning how to
obtain the absolute optimal perfection from their code. Don's results *are*
useful, but not in the way you say we're claiming.
Louis Wasserman
wasserman.louis@gmail.com
On Sat, Feb 21, 2009 at 5:35 PM, Bulat Ziganshin
Hello Louis,
Sunday, February 22, 2009, 2:30:23 AM, you wrote:
yes, you are right. Don also compared results of 64x-reduced computation with full one. are you think that these results are more fair?
Observation:
The best gcc result shown in the thread, if I recall, precomputed the result of the full computation at compiletime and simply outputted it, when we looked at the assembly.
While I will accept that this could be seen as an optimization GHC should have made, I do not accept that this will be the case with most everyday code a programmer writes, as most code is not used to simply compute arithmetic constants.
For code that actively requires computation at runtime, I have seen no examples of an instance where well-optimized GHC is actually dozens or hundreds of times slower than GCC output.
Louis Wasserman wasserman.louis@gmail.com