On Sun, 2011-12-18 at 17:08 -0600, Andrei Alexandrescu wrote: > On 12/18/11 1:08 PM, Isaac Gouy wrote: > >> From: Russel Winder > >> Subject: Re: Java> Scala > >> Newsgroups: gmane.comp.lang.d.general > >> Sat, 17 Dec 2011 22:18:26 -0800 > > > >> I really rather object to being labelled an educated idiot. > > .... > >> If you want to look at even more biased benchmarking look at > >> http://shootout.alioth.debian.org/ it is fundamentally designed to show > >> that C is the one true language for writing performance computation. > > > > I rather object to the baseless accusation that the benchmarks game is > > "designed to show that C is the one true language for writing performance > > computation."
Overstated perhaps, baseless, no. But this is a complex issue. > > Your accusation is false. > > > > Your accusation is ignorant (literally). The recent thread between Caligo, myself and others on this list should surely have displayed the futility of arguing in this form. > It also strikes me as something rather random to say. Far as I can tell > the shootout comes with plenty of warnings and qualifications and uses a > variety of tests that don't seem chosen to favor C or generally systems > programming languages. The Shootout infrastructure and overall management is great. Isaac has done a splendid job there. The data serves a purpose for people who read between the lines and interpret the results with intelligence. The opening page does indeed set out that you have to be very careful with the data to avoid comparing apples and oranges. The data is presented in good faith. The system as set out is biased though, systematically so. This is not a problem per se since all the micro-benchmarks are about computationally intensive activity. Native code versions are therefore always going to appear better. But then this is fine the Shootout is about computationally intensive comparison. Actually I am surprised that Java does so well in this comparison due to its start-up time issues. Part of the "problem" I alluded to was people using the numbers without thinking. No amount of words on pages affect these people, they take the numbers as is and make decisions based solely on them. C, C++ and Fortran win on most of them and so are the only choice of language. (OK so Haskell wins on the quad-core thread-ring, which I find very interesting.) As I understand it, Isaac ruins this basically single handed, relying of folk providing versions of the code. This means there is a highly restricted resource issue in managing the Shootout. Hence a definite set of problems and a restricted set of languages to make management feasible. This leads to interesting situation such as D is not part of the set but Clean and Mozart/Oz are. But then Isaac is the final arbiter here, as it is his project, and what he says goes. I looked at the Java code and the Groovy code a couple of years back (I haven't re-checked the Java code recently), and it was more or less a transliteration of the C code. This meant that the programming languages were not being shown off at their best. I started a project with the Groovy community to provide reasonable version of Groovy codes and was getting some take up. Groovy was always going to be with Python and Ruby and nowhere near C, C++, and Fortran, or Java, but the results being displayed at the time were orders of magnitude slower than Groovy could be, as shown by the Java results. The most obvious problem was that the original Groovy code was written so as to avoid any parallelism at all. Of course Groovy (like Python) would never be used directly for this sort of computation, a mixed Groovy/Java or Python/C (or Python/C++, Python/Fortran) would be -- the "tight loop" being coded in the static language, the rest in the dynamic language. Isaac said though that this was not permitted, that only pure single language versions were allowed. Entirely reasonable in one sense, unfair in another: fair because it is about language performance in the abstract, unfair because it is comparing languages out of real world use context. (It is worth noting that the Python is represented by CPython, and I suspect PyPy would be a lot faster for these micro-benchmarks. But only when PyPy is Python 3 compliant since Python 3 and not Python 2 is the representative in the Shootout. A comparison here is between using Erlang and Erlang HiPE.) In the event, Isaac took Groovy out of the Shootout, so the Groovy rewrite effort was disbanded. I know Isaac says run your own site, but that rather misses the point, and leads directly to the sort of hassles Walter had when providing a benchmark site. There is no point in a language development team running a benchmark. The issues are perceived, if not real, bias in the numbers. Benchmarks have to be run by an independent even if the contributions are from language development teams. > But I'm sure Russel had something in mind. Russel, would you want to > expand a bit? Hopefully the above does what you ask. The summary is that Isaac is running this in good faith, but there are systematic biases in the whole thing, which is entirely fine as long as you appreciate that. -- Russel. ============================================================================= Dr Russel Winder t: +44 20 7585 2200 voip: sip:russel.win...@ekiga.net 41 Buckmaster Road m: +44 7770 465 077 xmpp: rus...@russel.org.uk London SW11 1EN, UK w: www.russel.org.uk skype: russel_winder
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