[pron]

> It's not that the benchmarks game is not a good benchmark suite, it isn't a benchmark suite.

OK, but I was responding to someone who did consider it to be a benchmark suite. As long as we agree it's not a good benchmark suite whatever it considers itself to be, we're in agreement.

> It's not that the benchmarks game is not a good comparison of language speeds, it's that comparison of "language speeds" is so under-specified as-to-be wishful thinking.

With that I completely agree. But if you group results by language, that's exactly what you're inviting, and if your suite of benchmarks or whatever you want to call it covered a wider range of problems, that point could be more easily seen. Let's say that the combination of grouping results by language and covering only a very narrow (and niche) set of problems that also happens to be the sweet spot of some languages that have other significant performance failings in other use cases doesn't exactly help people get the right impression.

[igouy]

> As long as we agree…

Close enough.

> … help people get the right impression.

The target audience wonder "Which programming language is fastest?"

A table or chart sorted by elapsed time is the answer they expect.

The target audience have various (perhaps un-examined) ideas about the question.

The sources and measurements can be a way to examine and discuss some of those ideas.

[pron]

Ok, but if the measurements were wider in scope they could at least offer a more interesting, well-rounded, and perhaps even relevant basis for discussion (even if the other flaws, which are harder to fix, remained).

[igouy]

Once upon a time, I might have imagined that would be so. Now it seems more like squeezing a lemon, there's hardly any more after the first squeeze.

https://benchmarksgame-team.pages.debian.net/benchmarksgame/...

[pron]

I think you're referring to the less important point I made. Correcting for apples-to-apples is harder and less valuable. Having more domain coverage is easier and more valuable (especially since the current coverage is so narrow and largely irrelevant to most software).

BTW, what we do is compare our suite of micro-benchmarks to our (much smaller) suite of macro-benchmarks. This way we get at least some sense of how relevant the microbenchmarks are (i.e. we're looking at the correlation of the deltas). Some microbenchmarks are more correlated with the macrobenchmarks than others. If an optimisation helps some microbenchmarks that we think are not representative of many programs and doesn't help with any macrobenchmark - we take it out.

Just to give an example, we may want to measure some optimisation that helps some allocation pattern. Sometimes it turns out that if that pattern is diluted by other allocation patterns the program does for other tasks, the advantage is completely erased. Some optimisations in free-list allocators are particularly susceptible to this: if your program allocates only in this specific way, it will be super fast. If, in addition, there are some sporadic allocations that follow a different pattern, then after an hour you'll see performance start to drop.

[igouy]

> apples-to-apples

Hopefully, some of the target audience might try to confirm that programs are what they think of as "comparable".

> Having more domain coverage is easier and more valuable…

So where are the examples of that being done? (It's been decades.)

[pron]

> So where are the examples of that being done?

Whenever people want to get valuable information. As I said, we in OpenJDK have a couple hundred benchmarks, some macro, many micro, which are meant to give a decent coverage of the things that affect performance.

If a website wants to group results by languages, it should think about performance from the perspective of how languages work (which include compilers, linkers, and runtimes).

For example, what compiler/linker optimisations are done can depend a lot on whether the program is in a single compilation unit or multiple (and in the case of C and C++ - it does).

On the runtime front, think about memory management. These mechanisms often have different behaviour depending on whether the objects are of similar size or not, whether they're allocated and freed by multiple threads or a single one, and whether the heap is "young" and unfragmented or old and fragmented.

Another area in runtimes is data structures. Are they single-threaded or concurrent, and if concurrent, how do they behave under low and high contention?

Some mechanisms, in all of these levels, have great performance under some conditions and not so great performance in others, and sometimes where they perform great is actually a condition that is encountered less often in real programs.

If you're asking what multi-lingual benchmark suites offer good coverage - I don't know. But that we don't have good information doesn't mean that it's good to offer bad information. Imagine that in American presidential elections there were no national polls and no polls in most states. Would having a poll only in Alabama or only in California offer good insight into who's likely to win? Probably not, because such a poll offers a very partial view of the situation. Is it better than nothing? Maybe, but not by much, because the outcome in Alabama and California is easy to predict without any polls, so it's only helpful in the most extreme cases.

My point is that bad information is bad information, and if people don't understand how different languages behave under different conditions (e.g. that the optimisations the compiler does can differ depending on whether the program is in a single file or not) then they can get the wrong impression. Imagine that someone has no idea about the regional polarisation in the US, and you tell them, well, there are 50 states, but since we don't have polls for all of them, here's the poll for Alabama. Is that information helpful at all?

In any event, any increase in the coverage makes the information a little better, and because the audience may not know whether multiple benchmarks exercise the same or different behaviour in the language, it's the role of the website to pick problems that trigger the different codepaths in the languages' infrastructure. Otherwise, there's the wrong impression of variety, like saying we don't poll only in Alabama but also in Mississippi. Or it's like testing the structure of a bridge by driving a car across it, and then doing it with ten different car models. Testing a bridge does require variety, but the different car models are not what triggers different conditions for the bridge.