eventcore vs boost.asio performance?

[Sönke Ludwig]

Am 19.02.2023 um 20:53 schrieb zoujiaqing:
> eventcore is a very good and stable network library based on the 
> Proactor model.
> These high-performing C++ frameworks all use asio.
> What can we achieve if we use eventcore as network io?
> 
>   * https://github.com/vibe-d/eventcore
>   * 
> https://www.techempower.com/benchmarks/#section=data-r21&hw=cl&test=plaintext

I'm not sure where it would be today on that list, but I got pretty 
competitive results for local tests on Linux a few years back. However, 
there are at least two performance related issues still present:

- The API uses internal allocation of memory for I/O operations and per 
socket descriptor. This is to work around the lack of a way to disable 
struct moves (and thus making it unsafe to store any kind of pointer to 
stack values). The allocations are pretty well optimized, but it does 
lead to some additional memory copies that impede performance.

- On both, Linux and Windows, there are new, faster I/O APIs: io_uring 
and RIO. A PR by Tobias Pankrath 
(https://github.com/vibe-d/eventcore/pull/175) for io_uring exists, but 
it still needs to be finished.

Another thing that needs to be tackled is better error propagation. 
Right now, there is often just a generic "error" status, without the 
possibility to get a more detailed error code or message.

By the way, although the vibe.d HTTP implementation naturally adds some 
overhead over the raw network I/O, the vibe.d results in that list, 
judging by their poor performance on many-core machines, appear to be 
affected by GC runs, or possibly some other lock contention, whereas the 
basic HTTP request handling should be more or less GC-free. So those 
shouldn't be used for comparison.