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Comment by felixgallo | Hacker News Reader

Paraphrasing the late great Joe Armstrong, the great thing about Erlang as opposed to just about any other language is that every year the same program gets twice as fast as last year.

Manycores hasn't succeeded because frankly the programming model of essentially every other language is stuck in 1950. I, the program, am the entire and sole thing running on this computer, and must manually manage resources to match its capabilities. Hence async/await, mutable memory, race checkers, function coloring, all that nonsense. If half the effort spent straining to get the ghost PDP-11 ruling all the programming languages had been spent on cleaning up the (several) warts in the actor model and its few implementations, we'd all be driving Waymos on Jupiter by now.

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I'm curious, which actor model warts are you referring to exactly?

[The obvious candidates from my point of view are (1) it's an abstract mathematical model with dispersed application/implementations, most of which introduce additional constraints (in other words, there is no central theory of the actor model implementation space), and (2) the message transport semantics are fixed: the model assumes eventual out-of-order delivery of an unbounded stream of messages. I think they should have enumerated the space of transport capabilities including ordered/unordered, reliable/unreliable within the core model. Treatment of bounded queuing in the core model would also be nice, but you can model that as an unreliable intermediate actor that drops messages or implements a backpressure handshake when the queue is full.]

I don't think either of those are particularly problematic. The actor model as implemented by Erlang is concrete and robust enough. The big problems with the actor model are, in my opinion, around (1) speed optimizations for immutable memory and message passing (currently, there's a great deal of copying and pointer chasing involved, which can be slow and is a ripe area for optimization), (2) (for Erlang) speed and QOL improvements for math and strings (Erlang historically is not about fast math or string handling, but both of those do comprise a great deal of general purpose programming), (3) (for Erlang) operational QOL misc improvements (e.g. existing distribution, ets, amnesia, failover, hot upgrade, node deployment, build process range from arcane (amnesia, hot upgrades, etc.all the way up to covered-in-terrifying-spiders (e.g. debugging queuing issues, rebar3))

There is no lineage between The Actor Model and Erlang. The creators of Erlang are on record as having never heard of the Actor Model (as developed by Hewitt, Agha and colleagues at MIT). None of the points you make (including the first one) are a part of any formal definition or elaboration of the Actor Model that I have seen, which was one of my points: there is no unified theory of the Actor Model that addresses all of the practical issues.

With respect to your point (1), you might be interested in Pony, which has been discussed here from time to time, most recently: https://news.ycombinator.com/item?id=44719413 Of course there are other actor-based systems in wide use such as Akka.

Can you explain the joe armstrong quote a bit to someone not familiar with the language?

Erlang's runtime system, the BEAM, automatically takes care of scheduling the execution of lightweight erlang processes across many cpus/cores. So a well written Erlang program can be sped up almost linearly by adding more cpus/cores. And since we are seeing more and more cores being crammed into cpus each year, what Joe meant is that by deploying your code on the latest cpu, you've doubled the performance without touching your code.

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