[zeromq-dev] Preliminary results of voting

[Martin Sustrik]

Pieter,

>> The next desired item - surprisingly - is to lower the latency from
>> current 30 us to 10 us (5 votes). I have no idea what conclusion to make
>> from this. 30 us is as low as you can get on commodity hardware and
>> standard networking stack.
> 
> This is the cost of pushing a single message through the stack and
> back up the other side, right?  If you bundle messages you can cut
> this latency.  Does 0MQ bundle outgoing messages, by emptying its
> queue?  We're looking at doing this in OpenAMQ to improve throughput
> (and cut latency).

No. Bundling two messages into single packet will make the second one 
have the same latency as if it was sent alone it its own packet. The 
first one will have a slightly higher latency because it has to wait for 
the second message to be submitted.

So, 0MQ does bundle messages to get better throughput, however, that 
doesn't improve latency in any way. AFAICS the only way to get latency 
lower at the moment is to mess with underlying networking stack and/or 
hardware.

Martin