Actually I wasn't that interested in throughput, only the latency in terms of instructions executed since sending until it is received, though indeed the throughput is also superior with tokio.
For most applications this difference doesn't really matter, but maybe some applications do a lot of small things where it does matter? In those cases it might be an easy solution to switch from standard threads to tokio async and gain 10x speed, as the structure of the applications remains the same.
> It's a benchmark of the channels themselves and whatever locking/synchronization stuff they use.
Yeah, in retrospect some mutex-benchmark might be better, though I don't expect a message channel implemented on top of that is noticeably slower. A mutex benchmark is probably easier to get wrong..
> What would be more interesting is to have longer running jobs doing some task inside themselves and only periodically (ever few seconds, say) synchronizing.
I don't quite see how this would give any different results. Of course, in that case the time it takes to transmit the message would be completely meaningless.
> What's the tokio executor's settings by default there? Multithreaded or not? I'd be curious how e.g. whether tokio is actually using multiple threads or not here.
It's using the multithreaded executor. I tried the benchmark with #[tokio::main(worker_threads = 1)] and 2 and while with =1 the result was 529 but with =2 it was 566.