What's "slow"? What's "fast"? It depends. It depends on the program, the programmer, his or her hardware, the day of the week, the hour of the day, the season, what he or she had for lunch, ...

It's a never ending quest.

I, for exemple, am perfectly happy with the current benchmark of the rust compiler. I find a x2 improvement absolutly excellent.

- you don't reallocate the array

- you don't allow updating/ removing past inserted values

In essence it become a log, a Vec> or a Vec>>. Works well, but only for a bounded array. So applications like messaging, or inter-thread communication are not a perfect fit.

It's a fixed-size vector that can be read at the same time it's being written to. It's no a common need.

- 2 actors on 1 thread = OK

- 1 actor on 2 thread = you are probably doing it wrong.

As for the rest, whether or not they are used in communication systems and whether or not they are cpu-bound, consider there are and run the handle on a separate loop from the main message dispatching. Otherwise you _will_ delay messaging if handles don't await.

Right. It's not a very widespread use case, to be honest. You'd find that most would be N actors for M threads (where N <= M ; an Actor in itself is never shared among multiple threads [So `Send` and not `Sync`, in theory] - an inner message handler _could_ have parallel processing but that's up to the user)

I think you should assume in Kameo that every Actor's message handler is going to be CPU-bound. For example, it means that your internal message dispatch and Actor management should be on a separate loop from the User's `async fn handle`. I don't know if it's already the case, but it's an important consideration for your design.

Nice library, BTW, I think it checks all the marks and I like your design. I've tried most of them but could not find one that I liked and/or that would not have a fatal design flaw (like async_traits, ...) :)

PS : Multi-threaded tokio runtime should be the default. Nobody wants a single-threaded actor runtime. It should be in capital letters in the readme.

They run in separate tasks / threads anyway and they are cpu-bound. So, why would it be necessary to make them async ?

https://zeromq.org/

Yes and I do think they are fundamentally incorrect or they cannot be translated to the log use case.

I also agree that, performance-wise, the lock make little difference. In fact my old benchmarks tend to point that locks were MORE EFFICIENT than atomics on ARM64 (MBP M1), for example. It's more like a fun little exercise, and also to confirm that I'm not completely dumb and that the problem is not solvable with the simple use of 2 atomics and a counter.

So the linked list would involve going through all the links and following end tail refs/pointers. It would make reading O(n) and that's a Nope.

However, you could imagine having a Vec index that contains a ref to all allocated inner-logs, and query the index first in order to obtain the buffers' location. That works, but then the index has to go through a lock (either a RWLock or a mutex) as the CaS operation isn't enough if we get to the end of the index and it needs to be reallocated. It's fine, and I think that's the most appropriate solution.

PS : In fact, there is a sweet spot where you'd like to have a semi-unbounded log. If your index is big enough to contain something like 4Md entries, you'd probably end-up splitting the log in several pieces for archiving and performances purposes. Loading the log (fully or partially) from disk efficiently is then more important than having a real unbounded log. Then you would not necessarily use a lock and could CaS in the index.

It's not that FIII is bad at was it was doing, but simply Actual was a bit faster, a bit simpler, a bit more practical to use when importing. I'm mostly using rules, categories and reporting.

Comments URL: https://news.ycombinator.com/item?id=39370801

Points: 3

# Comments: 0

Arc-Mutex yes, Arc-Box no.

It's like "I want a shared, immutable reference to something recursive, or unsized". The heap part makes no sense because it's already allocated there if you use an Arc : https://doc.rust-lang.org/std/sync/struct.Arc.html

> The type Arc provides shared ownership of a value of type T, allocated in the heap.

Moreover, you don't even need the box for a dyn : https://gist.github.com/rust-play/f19567f8ad4cc00e3ef17ae6b3...