Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why is BIND 10 written in C++ and Python?

isc.org

Post reply on HN
Print view View original

51–60 of 136 posts

Re: Why is BIND 10 written in C++ and Python?

#51

Post by Symmetry »

illumen wrote: post #35
bnegreve wrote: post #16

Earlier quoted context omitted.

Hum, I don't think interpreting this comment as Python is not adequate for performance critical applications is misinterpretation. The author makes it very clear in some other part of the text: > [Python] has all of the features that we were looking for… except performance. Now your interpretation is also valid since they could have written everything in C++ but they didn't.

There is a python DNS server running on pypy that seems to get a pretty big speedup over CPython. Here is the benchmark result: http://speed.pypy.org/timeline/#/?exe=3,6,1,5&base=2+472... 0.002 for pypy VS 0.015 for CPython, which is 6.66 times faster. So, for the last couple of years they have been wrong - since PyPy has shown pretty good performance in a DNS benchmark, so Python can have pretty good performance ;)

Performance isn't a quality that is either present or not present, it's a quantity you can measure with a number as you did. It's true that pypy is much faster than CPython, but it's also true that C++ is much faster than pypy. Cpython is normally about 2 orders of magnitude slower than C++ on computationally intensive workloads, and if pypy get that down to a single order of magnitude that's great... but not enough here.

Re: Why is BIND 10 written in C++ and Python?

#52

Post by nicholassmith »

justin66 wrote: post #47
nicholassmith wrote: post #13

I think it's interesting that they did consider C and then decided it was too much of a risk. There's a constant theme of 'why use C++? C is faster and doesn't suck as much!' especially due to Linus' statements on the language, but often C is a technical risk as there's so much more that can go wrong. I'm not saying C++ is a better language than C, but it's definitely different and given the language is structured to…

It's a tangent, but: has Linus ever given a presentation that involved actually discussing code? Perhaps code projected on a screen, even part of a slideshow? It's odd that he's such an accomplished engineer but every presentation I've seen him give involves saying outrageous things while starry-eyed geeks stare at him adoringly. If it weren't for the fact that he's arguing from a position of (very great) authority,…

Well, I've not seen any but that doesn't preclude him actually giving them but I'm sure he has said in interviews he mostly just does email and patch wrangling rather than actual coding these days.

He's loud and opinionated and one of the tech folk heroes, his opinion is going to be listened too and often parroted due to it, even if it's just his opinion rather than a technical fact.

Re: Why is BIND 10 written in C++ and Python?

#53

Post by reidrac »

stefantalpalaru wrote: post #3

This doesn't look good for Python: "Whenever possible, we use Python" "When necessary, we use C++" "As of right now, it ends up that about 75% of our code is C++ and 17% is Python (link) since it turns out that a lot of BIND 10 is performance-critical."

It could mean that you need more C++ to do stuff (or less Python code to do stuff, whatever your like).

What I'm saying is that "amount of code" is not a valid magnitude when comparing different languages.

In my experience converting some unmaintained Perl tools to Python, the Python version was almost as long as the Perl one, but it included more functionality, comments and error handling (I'm not criticising Perl here but the unmaintained code that I had to convert).

Re: Why is BIND 10 written in C++ and Python?

#54

Post by papsosouid »

nicholassmith wrote: post #13

I think it's interesting that they did consider C and then decided it was too much of a risk. There's a constant theme of 'why use C++? C is faster and doesn't suck as much!' especially due to Linus' statements on the language, but often C is a technical risk as there's so much more that can go wrong. I'm not saying C++ is a better language than C, but it's definitely different and given the language is structured to…

>but often C is a technical risk as there's so much more that can go wrong.

That is objectively incorrect. There is much less that can go wrong with C, as there is much less period. Everything that you can do incorrectly with C, you can do incorrectly with C++, plus 10 times more things that C++ introduced. The idea that C++ is safer because "we just won't do dangerous stuff" is silly, as any language is safe if you "don't do dangerous stuff", including C.

Re: Why is BIND 10 written in C++ and Python?

#55

Post by papsosouid »

misnome wrote: post #5
stefantalpalaru wrote: post #3

This doesn't look good for Python: "Whenever possible, we use Python" "When necessary, we use C++" "As of right now, it ends up that about 75% of our code is C++ and 17% is Python (link) since it turns out that a lot of BIND 10 is performance-critical."

Why doesn't it look good for python? As far as I'm aware, Python has never been advertised as a top-performance language, and part of the advantage has always been that you can rewrite performance-critical paths in c. Adding to this, the fact that BIND is something pretty performance-intensive, I don't think this makes it look bad at all.

>Why doesn't it look good for python?

Because it directly contradicts the "only 20% of your code is performance sensitive and the other 80% can be scripting language X" nonsense that scripting language apologists constantly parrot with no evidence. This is a good example of how scripting languages are in fact not well suited to application development, and should instead be used for scripting.

Re: Why is BIND 10 written in C++ and Python?

#56

Post by [deleted] »

alpatters wrote: post #28
jejones3141 wrote: post #19

Here's what I take from this: "C++ is by no means an easy language to work with, so the idea is that we will avoid its complexity when possible."

Avoiding its complexity does not mean avoiding it. E.g. you could avoid template metaprogramming due to its complexity whilst keeping to simpler areas of the language. C++ is a large, multi-paradigm language. It gives you choices and one is free to abuse those choices. But having more options gives you more power to express. I think with modern C++ style, boost and C++11 its "difficult-to-work-with" reputation is mas…

[deleted]

Re: Why is BIND 10 written in C++ and Python?

#57

Post by zxcdw »

justin66 wrote: post #47
nicholassmith wrote: post #13

I think it's interesting that they did consider C and then decided it was too much of a risk. There's a constant theme of 'why use C++? C is faster and doesn't suck as much!' especially due to Linus' statements on the language, but often C is a technical risk as there's so much more that can go wrong. I'm not saying C++ is a better language than C, but it's definitely different and given the language is structured to…

It's a tangent, but: has Linus ever given a presentation that involved actually discussing code? Perhaps code projected on a screen, even part of a slideshow? It's odd that he's such an accomplished engineer but every presentation I've seen him give involves saying outrageous things while starry-eyed geeks stare at him adoringly. If it weren't for the fact that he's arguing from a position of (very great) authority,…

> It's odd that he's such an accomplished engineer but every presentation I've seen him give involves saying outrageous things while starry-eyed geeks stare at him adoringly.

Why is this? Because the man delivers.

Re: Why is BIND 10 written in C++ and Python?

#58

Post by hcarvalhoalves »

jerf wrote: post #39
illumen wrote: post #35

Earlier quoted context omitted.

There is a python DNS server running on pypy that seems to get a pretty big speedup over CPython. Here is the benchmark result: http://speed.pypy.org/timeline/#/?exe=3,6,1,5&base=2+472... 0.002 for pypy VS 0.015 for CPython, which is 6.66 times faster. So, for the last couple of years they have been wrong - since PyPy has shown pretty good performance in a DNS benchmark, so Python can have pretty good performance ;)

As much as I respect and appreciate Pypy, BIND is one of the core foundational pieces of the internet. It needs to be bulletproof and robust. I don't think Pypy itself qualifies as a mainstream enough language for them to build BIND on. This isn't a slight on Pypy, because the core problem is simply that it hasn't been around for long enough and subjected to enough stress to earn entry into the highest of the high ti…

> I don't think Pypy itself qualifies as a mainstream enough language for them to build BIND on.

Minor pedantry: PyPy is not a language. It's an alternative compiler/runtime for Python.

Post reply on HN