> 5. I wonder which implementation of Lua they used. Lua can be pretty fast, one of the fastest dynamic languages out there.
Apparently 5.3, but I am very skeptical of these results. Also the way the data is organised is very weird. One should not compare a JIT compiled VM (JavaScript) with interpreters (Lua, Python, Ruby...). An honest approach would have used LuaJIT, PyPy etc. or separated the languages into "families" better. Not to mention the choice of algorithms they used. Some of the algorithms in the benchmark game have many flaws.
As it was already stated in this thread, some of the Python ones were multithreaded but the ones in Lua weren't. Why? In a different benchmark I've seen algorithms using C wrappers for Python, but not in Lua. While I understand wrapping C and multithreading reflect the industry use in Python, so they do in Lua. Benchmarks are useless if you are not consistent in the implementations of the things you are comparing with. It disgusts me, to be honest, when I see benchmarks comparing JIT compilers with vanilla Lua just to say "hey we're faster", as LuaJIT does not even exist. It looks like pure dishonesty. In the case of this paper in particular, as they do not represent any language, it strikes me as lack of research / understanding.
No mystery: someone has made the effort to contribute all those multi-process Python programs; no one has made the effort to contribute all those multi-process Lua programs.
Oh yes, that is true. But the person making the benchmarks should be aware of that and either look for better matching algorithms or implement them themselves.
If your intention is not to make a good comparison, then sure. I've seen other papers on language implementation and benchmarks, and researchers were way more careful than this, individually inspecting the algorithms they were using.
I happened to spot a problem on this one on the Lua part and also on some other parts concerning how they classify things, because it happens to be things I know more. I'm not going out of my way to look for problems in the rest of the paper because I'm not a reviewer and I have better things to do.
But if I was the one way conducting this academic research, then I would want the results not to be bogus. The difference here is this is not a blog post about some bullshit comparison someone is making. If that was the case, then alright, if public contributed algorithms failed to represent exactly what was being looked for, why not go for whatever is out there. I just expect a more rigorous procedure from academics.
> Are they likely to be expert in all those programming languages?
No, but again, I take paper results very seriously. Misleading results are bad for science, period. Here is an example of more rigorous research: https://arxiv.org/pdf/1602.00602.pdf
> If Lua wasn't included would you complain ?
Maybe I would, who knows. I did also mention in another comment it would be nice if Julia was there. It depends how relevant they are for the research being conducted. As a language used very often in microcontrollers, Lua is very relevant for energy efficiency research. I don't know anything about Forth, but I wouldn't just dismiss people saying it should be there with "then contribute forth algorithms to the benchmarks game yourself".
"disgusts me" & "pure dishonesty" don't seem like a serious response.
> … an example of more rigorous research…
Which again uses programs that were contributed to the benchmarks game.
> … wouldn't just dismiss people…
I wouldn't just dismiss them: I'd tell them that others have every right to present what seems important to them, and exclude what seems less important -- without being accused of dishonesty.
Because they're "different families" of language implementation. A Just In Time compiler is a compiler. It looks like an interpreter, but it compiles the code to machine code and runs it.
And obviously the performance of programs using those language implementations on the same computer under the same workload may be measured and compared.
Why should "different families" of language implementation not be compared?
Firstly, the paper separates languages into compiled languages and interpreted languages to begin with. So I was expecting it would follow this pattern correctly.
Secondly, why would you compare the performance of C and Ruby, for example? Ruby is bound to be slower for design reasons. Doing it to say "Look, C is fast!" doesn't mean anything. There are different reasons one would compare C and Rust, or C and Ruby. The way the results are displayed and what it tries to convey is very important.
If you're not making a baseline, or being very clear, etc. then it's just misleading to have a benchmark portraying Javascript as faster than Ruby, Python and Lua. Either you put those into their correct classifications clearly, or you compare it with LuaJIT, PyPy, Julia etc.
The paper, both shows tables that include all the results (ordered by Energy consumed) and shows separate charts for what the authors classify as "either a compiled, interpreted, or virtual-machine language".
What is "an interpreted language" ?
"Although we refer to Lua as an interpreted language, Lua always precompiles source code to an intermediate form before running it. … The presence of a compilation phase may sound out of place in an interpreted language like Lua. However, the distinguishing feature of interpreted languages is not that they are not compiled, but that any eventual compiler is part of the language runtime and that, therefore, it is possible (and easy) to execute code generated on the fly."
p57 "Programming in Lua" (2003)
> … why would you compare the performance of C and Ruby, for example? Ruby is bound to be slower…
Except when the C program is measured to be 50x slower than the Ruby program --
Lua is not compiled to machine code. It compiles to an intermediate bytecode, which is then interpreted. So you could say it is a VM. Also bear in mind, LuaJIT is not Lua. It's a different implementation.
I guess you misinterpreted my comment. I didn't imply there are no reasons to compare C and Ruby. I said the reason is important and the way you portray that, and the way you portray your results, changes things.
Do you think Roberto Ierusalimschy is confused about that ?
Again, here's what the creator of Lua says -- "… the distinguishing feature of interpreted languages is not that they are not compiled, but that any eventual compiler is part of the language runtime…"
EDIT:
Is that not what you mean by "interpreted language" ?
> Do you think Roberto Ierusalimschy is confused about that ?
No, of course not. I think you are. You are clearly misinterpreting his words. I will repeat, (PUC)Lua is not compiled to machine code, but to an intermediate bytecode form. Those are completely different things, and what I said does not come in conflict at all with the quote you took from PiL, so I don't know what you are confronting me about.
> Lua is not compiled to machine code, but to an intermediate bytecode form.
Correct.
Now look at what Roberto Ierusalimschy means by "interpreted language": "… the distinguishing feature of interpreted languages is not that they are not compiled, but that any eventual compiler is part of the language runtime and that, therefore, it is possible (and easy) to execute code generated on the fly."
Apparently 5.3, but I am very skeptical of these results. Also the way the data is organised is very weird. One should not compare a JIT compiled VM (JavaScript) with interpreters (Lua, Python, Ruby...). An honest approach would have used LuaJIT, PyPy etc. or separated the languages into "families" better. Not to mention the choice of algorithms they used. Some of the algorithms in the benchmark game have many flaws.
As it was already stated in this thread, some of the Python ones were multithreaded but the ones in Lua weren't. Why? In a different benchmark I've seen algorithms using C wrappers for Python, but not in Lua. While I understand wrapping C and multithreading reflect the industry use in Python, so they do in Lua. Benchmarks are useless if you are not consistent in the implementations of the things you are comparing with. It disgusts me, to be honest, when I see benchmarks comparing JIT compilers with vanilla Lua just to say "hey we're faster", as LuaJIT does not even exist. It looks like pure dishonesty. In the case of this paper in particular, as they do not represent any language, it strikes me as lack of research / understanding.