Erlang Performance Lab
erlang.pl
erlang.pl
I'd just like to say I found the homepage did a very good job of explaining the product. Good screenshots and well written summaries of each feature/benefit.
Edit: seconding the call for documentation. Also maybe a link to Getting Started at the top, that's seems like where I'd start vs downloading a .tar.gz without instructions.
Download link is a .gz and the getting started page goes nowhere really?
When you make tools for developers, the really important bit is communicating why this thing is useful, and then how to use it right?
Love to see Erlanger tools and I'll be following you, but this seems a smidge immature....
How does it work out network use? Does it depend on certain behaviours? Does it simply make pretty things from trace?
As for network traffic, we use net_kernel module which allows to track throughput between nodes in the cluster. It doesn't rely on specifics you system.
The gains you get for free using otp and the beam vm depend heavily around language integration of vm features. Porting python to a vm it would work slowly on and would be unable to use most of, if not all of, the benefits without changing the language would give you what exactly?
What couldn't you do, say by making BEAM/OTP -specific features be a library you import in Python, and by mapping Python language features to however Erlang does them?
I get there will likely be problems, but what specific problems would you run in to?
Python has no concept of a process like Erlang does. The standard library does even know about, let alone is able to deal with, the difference between cast and call messages. It can't do messages even. There is no way to translate monitors vs links. What's a node? .....
You could implement python syntax maybe, but python will never make sense on beam.
If it sounds like a good idea to do that when you are solving something horrible, then your better bet is to write that functionality in a beam language instead of trying to play beam in a language which can't do it.
This is a bit of a different world than most of us are used to. Porting python to the jvm or making it run on v8 are different goals than making something play in the beam space.
You could run single node python with a port to beam, but there would be no advantages to doing it. It would be slower and no one would use it. Beam langauges only get you something when you're doing distributed things really and python isn't equipped for playing those natively.
You could wrap it in some libs maybe, sure. But why would you?
I don't know that Python on the beam is a good idea / worth the work, but I don't think there's a fundamental issue here:
A process is more or less a thread, which Python already knows about.
Cast is just sending a message, which is erlang:msg(Dest, Msg); call is send a message plus selective receive. General receive is easy, call a function (not already available) and return the message. Selective receive is trickier, because python doesn't have a construct for matching like Erlang, so you'd have to figure out how to specify the possible message signatures you'd like to receive; plus extra work to get the make_ref mailbox marking optimization.
Monitors and links are just calling functions, and maybe being killed or getting specific messages later -- it's a VM feature, not a language feature. Same with a node.
You would have to make some hard decisions about any pythonic state though. It would be more functionally pure to pass that around as a function argument, but it might feel more like python if it was stuffed into the process dictionary. Python state shared between multiple processes/threads would be forbidden, of course. Mutability would also need some soul searching to fit into Beam's garbage collection.
EDIT to add: of course, you would need to restrict I/O to message passing -- anything with file descriptors should be rewritten to be message passing with beam ports.
Monitor/Link and Cast/Call are all built ontop of the regular message passing functionality of the language. The point I 'whitehat fibbed' to make stands though, python might be feasable as a syntax implementation but there's a _MASSIVE_ difference in the architecture of helloworld as a flask app and the same under cowboy; trying to get one to behave as the other makes no sense to me.
Implementing a python on beam makes no sense as to actually benefit from beam you'd need to write a lot of libraries to actually play with the environment and why would anyone bother?
And sorry but no, processes are not more or less threads. My laptop can do this:
3> processes:max(250000).
Max allowed processes: 262144
Process spawn time=3.408 (15.644) microseconds
Process teardown time=3.156 (1.552) microseconds
Preemptive scheduling is a big deal also.
I agree that it would be a lot different architecture than a normal python application; but where there could be value, is if you wanted to write a distributed thing in python with all the nice properties you get from an erlang system, your choices now are either drop python (my preference!); write dist/otp yourself, but in python (hard, because how do you bolt on monitors, etc); write just enough erlang to coordinate python running as port commands (probably doable, but could be fragile).
I personally would love to run a little bit of perl on the beam, but i know it's crazy, so I don't mention it very often ;)
"Mochi is a dynamically typed programming language for functional programming and actor-style programming. Its interpreter is written in Python3. The interpreter translates a program written in Mochi to Python3's AST / bytecode."
If all that can be done in Python 3, surely it could be ported to run on BEAM to good effect.
You'd have to create a Frankenstein interpreter to get anything working.
On a side note: One thing that always annoyed me about Erlanger is it's lackluster documentation, specifically browsing the docs. Amy efforts to improve that?