possible to include examples of using evmap across threads? about left-right HOT 2 CLOSED

Hi there!

evmap is primarily intended for the single-writer, multi-reader use-case; this is why you can have multiple read handles (i.e., ReadHandle: Clone), but only one write handle. Arc<Mutex<WriteHandle>> allows you to have multiple threads do writes, but they will need to do them sequentially (as the Mutex implies). You are completely right that this will not scale well when you have many writers, but that's the trade-off evmap makes. Instead, evmap is heavily optimized for when you have a lot of readers that all want to access the map concurrently (including while the writer is operating). This is why you don't need to wrap ReadHandle in an Arc<Mutex<_>>.

As for how to improve the documentation and/or examples, I'd be happy to hear what changes you would suggest making. Would a multi-threaded example be enough?

from left-right.

This is a great explanation, thank you. I think if you put essentially that text (with some edits to supply the context) in the docs it would go a long way. The other thing would just be an example of sending a clone()ed reader to another thread while needing the mutex for the writer, perhaps.

I've been thinking about this and this may make sense for my situation even if I need a mutex for the writer. Even though I have several threads that need to be able to write (< 20), they aren't writing very often (less than once a second) and are unlikely to be writing at the same time. If I get faster reads and about the same write time then it could be a win.

from left-right.