[elihu]

For years, I didn't see what the point of Erlang was. It might scale well, but if it takes an Erlang process running on a hundred processors to equal the performance of a single-threaded C application, what's the point?

When I learned a bit more about Erlang, I realized that the point is that there are a lot of applications that are IO bound rather than computation bound, and for those apps Erlang performs very well and is easy to program in. Crunching numbers the fastest isn't always the most important thing.

[rdtsc]

One of the main points of Erlang is fault tolerance. Everyone forgets about that and talks actors and scalability, which is fine. But without fault tolerance and proceses with isolated heaps it doesn't matter how fast the C code is, it can process millions of transaction a second, and then segfault, and the availability and transaction rate goes to 0 on that node.

The other advantage is power of abstraction. With Erlang it is easy to describe and program distributed system with lots concurrent components. Sure you can do it with C++, Java, and Node.js etc, but those things are awkward there -- either threads share memory and have to deal mutexes, or you in are in callback/promise hell.