Ask HN: On Rob Pike's Concurrency is not Parallelism? • Hacker News Board

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#51

Post by KirinDave » Mon, Jul 30, 2012, 8:06 PM UTC

zem wrote: post #50

rvirding wrote: post #42

Earlier quoted context omitted.

"I love Erlang but I cannot get the past the syntax." I cannot understand this hangup about syntax. Syntax is the easiest thing to learn with a new language, you just look it up. It's the semantics and usage where the real problems are. Erlang doesn't have static typing, it is dynamically typed. It has always been dynamically typed. And however you look at it doing highly concurrent systems with processes is much eas…

syntax is the user interface of the language. it is one of the parts you have to deal with on a constant basis, both writing and reading code. i can well see how an unpleasant syntax can be a constant, grating annoyance when dealing with a language. (i happen to really like erlang's syntax, but it definitely has very different aesthetics from javascript's)

Honestly? Erlang's syntax is not that bad. It's not great in that it has prolog legacy with uncanny valleys to C-legacy left and right, but it's effective.

Really the only really tricky thing for a newbie is strings.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#52

Post by aphyr » Mon, Jul 30, 2012, 8:16 PM UTC

aeden wrote: post #40

ryah wrote: post #37

Earlier quoted context omitted.

Node is popular because it allows normal people to do high concurrency servers. It's not the fastest or leanest or even very well put together - but it makes good trade offs in terms of cognitive overhead, simplicity of implementation, and performance. I have a lot of problems with Node myself - but the single event loop per process is not one of them. I think that is a good programming model for app developers. I lo…

"I love Erlang but I cannot get the past the syntax." I also thought this. For some reason though the more I use it the more I am coming around to its syntax. There are lots of gotchas when compared with other popular languages, but still its syntax has grown on me recently. At the opposite end of the syntactic spectrum is Lisp. The more I use Clojure the more I am loving it as well. "The future of server programming…

I agree. The future of server programming is also not spawning multiple child processes. The question I have is how far off is that future? I know that most of my web applications today simply run in multiple spawned OS processes.

Barring a massive shift in hardware architectures, shared access by cooperating threads is your only option for high-performance shared state. Look at core counts vs core flops for the last five years. Look at Intel's push for NUMA architectures. This is a long-scale trend forced by fundamental physical constraints with present architectures, and I don't see it changing any time soon.

Anyone telling you shared state is irrelevant is just pushing the problem onto someone else: e.g., a database.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#53

Post by zem » Mon, Jul 30, 2012, 10:58 PM UTC

KirinDave wrote: post #51

zem wrote: post #50

Earlier quoted context omitted.

syntax is the user interface of the language. it is one of the parts you have to deal with on a constant basis, both writing and reading code. i can well see how an unpleasant syntax can be a constant, grating annoyance when dealing with a language. (i happen to really like erlang's syntax, but it definitely has very different aesthetics from javascript's)

Honestly? Erlang's syntax is not that bad. It's not great in that it has prolog legacy with uncanny valleys to C-legacy left and right, but it's effective. Really the only really tricky thing for a newbie is strings.

these things are very much a matter of taste. what does "effective" mean with respect to syntax? for instance, lispers will argue that their syntax is effective because of the things it lets you do, but that's orthogonal to whether it's actually a pleasant syntax to program in, which comes down to personal taste[1]. likewise, i love mlish syntax, but opa, a language steeped in ml semantics, nonetheless switched to something more javascripty for their main syntax because it proved more popular[2]. and read through the wrangling over ruby versus python sometime - the two languages are very similar under the hood, but their respective syntaxes are one of the things proponents of each language complain about when they have to use the other.

[1] as larry wall famously said, "lisp has all the visual appeal of oatmeal with fingernail clippings mixed in."

[2] http://blog.opalang.org/2012/02/opa-090-new-syntax.html

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#54

Post by ticking » Tue, Jul 31, 2012, 10:49 AM UTC

ryah wrote: post #37

KirinDave wrote: post #33

Earlier quoted context omitted.

You know, ryah; I like your work ethic, I like your enthusiasm, I think you're a cool guy and it's great your project has so much traction. But you say things like this and it worries me. Because a lot of people look up to you and either you said this because you feel defensive about your project or you said it because you genuinely don't understand the cases we're talking about here. And this is a problem because a…

Node is popular because it allows normal people to do high concurrency servers. It's not the fastest or leanest or even very well put together - but it makes good trade offs in terms of cognitive overhead, simplicity of implementation, and performance. I have a lot of problems with Node myself - but the single event loop per process is not one of them. I think that is a good programming model for app developers. I lo…

There is a ton of Languages for erlangs BEAM,

My favorite: Joxa a Clojure inspired (really just inspired ;)) lisp http://joxa.org/

Then there are Elixir (mentioned already) and Reia, Both seem to be inspired by Ruby. http://reia-lang.org/ http://elixir-lang.org/

Erlang has a far superior computational model an implementation than Node, it can handle way more requests faster and is newcomer friendlier as any web request is simply a message received.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#55

Post by preist » Tue, Jul 31, 2012, 12:38 PM UTC

tholschuh wrote: post #46

ryah wrote: post #37

Earlier quoted context omitted.

Node is popular because it allows normal people to do high concurrency servers. It's not the fastest or leanest or even very well put together - but it makes good trade offs in terms of cognitive overhead, simplicity of implementation, and performance. I have a lot of problems with Node myself - but the single event loop per process is not one of them. I think that is a good programming model for app developers. I lo…

If you like Erlang but cannot get past its syntax you might want to give Elixir a try. http://elixir-lang.org/

Syntax looks very Ruby like.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#56

Post by silentbicycle » Tue, Jul 31, 2012, 4:34 PM UTC

zem wrote: post #53

KirinDave wrote: post #51

Earlier quoted context omitted.

Honestly? Erlang's syntax is not that bad. It's not great in that it has prolog legacy with uncanny valleys to C-legacy left and right, but it's effective. Really the only really tricky thing for a newbie is strings.

these things are very much a matter of taste. what does "effective" mean with respect to syntax? for instance, lispers will argue that their syntax is effective because of the things it lets you do, but that's orthogonal to whether it's actually a pleasant syntax to program in, which comes down to personal taste[1]. likewise, i love mlish syntax, but opa, a language steeped in ml semantics, nonetheless switched to so…

It takes a lot of chutzpah for Larry Wall to say anything critical about Lisp syntax. Larry Wall. Come on.

I'm not the author of the comment above, but I think Erlang's syntax is effective in that it strongly emphasizes computation by pattern matching. If you write very imperative code in it (as people tend to, coming from Ruby or what have you), yes, it will look gnarly. Good Erlang code looks qualitatively different. There are pretty good examples of hairy, imperative Erlang code being untangled in this blog post: http://gar1t.com/blog/2012/06/10/solving-embarrassingly-obvi...

The . , ; thing is a bit of a hack, admittedly -- I suspect that comes from using Prolog's read function to do parsing for the original versions of Erlang (which was a Prolog DSL), and reading every clause of a function definition at the same time. Prolog ends every top-level clause with a period, not "; ; ; ; .". (Not sure, but a strong hunch, supported by Erlang's history.) I got used to it pretty quickly, though.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#57

Post by rvirding » Tue, Jul 31, 2012, 5:25 PM UTC

zem wrote: post #50

rvirding wrote: post #42

Earlier quoted context omitted.

"I love Erlang but I cannot get the past the syntax." I cannot understand this hangup about syntax. Syntax is the easiest thing to learn with a new language, you just look it up. It's the semantics and usage where the real problems are. Erlang doesn't have static typing, it is dynamically typed. It has always been dynamically typed. And however you look at it doing highly concurrent systems with processes is much eas…

syntax is the user interface of the language. it is one of the parts you have to deal with on a constant basis, both writing and reading code. i can well see how an unpleasant syntax can be a constant, grating annoyance when dealing with a language. (i happen to really like erlang's syntax, but it definitely has very different aesthetics from javascript's)

I think it would be dangerous if Erlang's syntax were to resemble that of another language like Java or C. Especially for beginners. That is because if things look the same you expect them to behave the same, and Erlang's semantics is very different from those languages whose syntax people think it should be like.

There is no getting around the difference in semantics. For this I think that having a different syntax is actually better. Also there are things in Erlang which are hard to fit syntactically into the syntax of OO languages, for example pattern-matching.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#58

Post by KirinDave » Tue, Jul 31, 2012, 5:34 PM UTC

ryah wrote: post #38

aphyr wrote: post #30

Earlier quoted context omitted.

Don't believe me? Try it: Node.js: https://gist.github.com/3200829 Clojure: https://gist.github.com/3200862 Note that I picked the really small messages here--integers, to give node the best possible serialization advantage. $ time node cluster.js Finished with 10000000 real 3m30.652s user 3m17.180s sys 1m16.113s Note the high sys time: that's IPC. Node also uses only 75% of each core. Why? $ pidstat -w | grep node 1…

Yep, serialized message passing between threads is slower - you didn't have to go through all that work. But it doesn't matter because that's not the bottleneck for real websites. Also Node starts up in 35ms and doesn't require all those parentheses - both of which are waaaay more important.

It is definitely a bottleneck I face daily in designing crowdflower. Our EC2 bill is much higher than it could be because we have to rely so much on process-level forking.

A great example of this is resque. It'd be great if we could have multiple resque workers per process per job type. This would save a ton of resources and greatly improve processing for very expensive classes of jobs. It's a very real-world consideration. But instead, because our architecture follows this "share nothing in my code, pass that buck to someone else" model like a religion, we waste a lot of computing resources and lose opportunities for better reliability.

What I find most confusing about this argument is that I challenge you to find me a website written in your share nothing architecture that, at the end of the day, isn't basically a bunch of CRUD and UX chrome around a big system that does in-process parallelism for performance and consistency considerations. Postgresql, MySQL, Zookeeper, Redis, Riak, DynamoDB ... all these things are where the actual heavy lifting gets done.

Given how pivotal these things are to modern websites, it's bizarre for you to suggest it is not something to consider.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#59

Post by rvirding » Tue, Jul 31, 2012, 5:35 PM UTC

silentbicycle wrote: post #56

zem wrote: post #53

Earlier quoted context omitted.

these things are very much a matter of taste. what does "effective" mean with respect to syntax? for instance, lispers will argue that their syntax is effective because of the things it lets you do, but that's orthogonal to whether it's actually a pleasant syntax to program in, which comes down to personal taste[1]. likewise, i love mlish syntax, but opa, a language steeped in ml semantics, nonetheless switched to so…

It takes a lot of chutzpah for Larry Wall to say anything critical about Lisp syntax. Larry Wall. Come on . I'm not the author of the comment above, but I think Erlang's syntax is effective in that it strongly emphasizes computation by pattern matching. If you write very imperative code in it (as people tend to, coming from Ruby or what have you), yes, it will look gnarly. Good Erlang code looks qualitatively differe…

As in Prolog ',' and ';' are separators: ',' behaves like an and, first do then and then do this (as in Prolog); while ';' is an or, do this clause or do this clause (again as in Prolog). '.' ends something, in this case a function definition. Erlang's functions clauses are not the same as Prolog's clauses which explains the difference.

It is very simple really, think of sentences in English and it all becomes trivially simple.How many sentences end in a ';'?. And you almost never need to explicitly specify blocks.

Here http://ferd.ca/on-erlang-s-syntax.html are some alternate ways of looking at it.

Re: Ask HN: On Rob Pike's Concurrency is not Parallelism?

#60

Post by KirinDave » Tue, Jul 31, 2012, 5:36 PM UTC

ryah wrote: post #37

KirinDave wrote: post #33

Earlier quoted context omitted.

You know, ryah; I like your work ethic, I like your enthusiasm, I think you're a cool guy and it's great your project has so much traction. But you say things like this and it worries me. Because a lot of people look up to you and either you said this because you feel defensive about your project or you said it because you genuinely don't understand the cases we're talking about here. And this is a problem because a…

Node is popular because it allows normal people to do high concurrency servers. It's not the fastest or leanest or even very well put together - but it makes good trade offs in terms of cognitive overhead, simplicity of implementation, and performance. I have a lot of problems with Node myself - but the single event loop per process is not one of them. I think that is a good programming model for app developers. I lo…

I do not see how you can simultaneously care about making programming better but not care about how people use what you're making to solve that problem.

Programming is a verb describing what people do with programming systems, and we're nowhere near the point where it can be done automatically yet. You cannot remove people from the equation and claim to be interacting with it.