First off, I never got around to thanking the list for resolving our 
multiple-identical-subscription notification issue. I appreciate the quick fix 
there, it helps a lot.

After reviewing a lot of the list's history of questions about UDP support in 
zeromq, I've got some of my own:

- What sort of performance increases could we see with UDP transport over TCP 
transport in zeromq, if it were a feature? The overall end-to-end latency 
between a zmq_msg_send() in one application on one host and zmq_msg_recv() in 
another application on the same host over the loopback interface is just too 
high for what we need. Initial profiling suggests that a non-negligible amount 
of that latency is bound up in zeromq and networking land. Is it possible to 
take a swing at how significant a decrease we would see in this latency by 
using UDP instead? I.e., are we talking an order of magnitude, or more like 
5-10%? Ultimately, we'll have messages sent inter-host instead of intra-host, 
and our environment is not inherently lossy, but possibly congested. That is, a 
lot of small messages are going out frequently, but the total throughput 
experienced by the network is unlikely to be high. The drawbacks of UDP 
(packets out of order, packet loss) are acceptable for our use case, and a 
packet that shows up too late is better off never showing up at all.

- If UDP could help us, what options are available to have it baked into 
zeromq? I understand it's not enough to express interest in a feature and 
expect it to magically show up. Roughly speaking, where in the code would be a 
good place to start building this in? In terms of effort and/or time taken, can 
you take a really rough swing at estimating it? Thanks,

Dan
_______________________________________________
zeromq-dev mailing list
[email protected]
http://lists.zeromq.org/mailman/listinfo/zeromq-dev

Reply via email to