[zeromq-dev] any examples of using downstream/upstream sockets?

Martin Sustrik sustrik at 250bpm.com
Sun Mar 28 09:10:29 CEST 2010

Hi Anton,

> Thank you for the great library, it seems it fits my needs well and
> it's performance is amazing!
> I've played with req/rep socket pair a bit and everything seems to be
> ok with them. But I've found no examples of using DOWNSTREAM/UPSTREAM
> sockets 


>(I'm especially interested in C and Python bindings). So I've
> just took zeromq-2.0.6/perf/local_lat.c and k
> zeromq-2.0.6/perf/remote_lat.c, changed socket types there and removed
> send() part of the loop from UPSTREAM side and recv() from DOWNSTREAM.
> Unfortunatelly, it seems it's not enough. Upstream side does not
> always quit after runing downstream one with the same amount of
> messages to transmit. Sometimes upstream side recieves message with
> zero length. Sometimes downstream side crashes with message "No such
> file or directory
> rc != -1 (epoll.cpp:83)" (I'm using linux 2.6.33 x86-64)
> And probably the most bad thing is that downstream side looks like
> everything is ok when upstream one is not even running! It reports
> that average latency is about 0.1 us. I'd love to see such latency if
> it really works.

Nope. There were several reports of such a behaviour. Unfortunately, I 
haven't been able to reproduce it yet :( Can you pass your test program?


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