[zeromq-dev] zmq build, examples, packaging

[Martin Sustrik]

Dirk Eddelbuettel wrote:
> Hi Martin,
> 
> On 9 December 2009 at 13:34, Martin Sustrik wrote:
> | Hi Dirk,
> | 
> | > Ok. I also quickly packaged Tk-Graph for internal use and am now running with
> | > freshly built zeromq_1.0.1 packages based on the git repo thanks to Pavol's
> | > patches.  [ BTW graph.pl didn't get installed along with the exchange/
> | > examples, it probably should. ]
> | 
> | Yes, I would say so.
> | 
> | > I currently have two machines '1' and '2'.  They are on the same subnet and
> | > both four-core cpus, albeit not the very newest,
> | > 
> | > I have  '1'   running     zmq_server,  gwt  and   stat | graph.pl
> | >         '2'   runing      me 
> | > so that there should be actual cross-machine traffic.
> | > 
> | > But that's not what I am seeing.  While the plot for latency is low (sub 500
> | > usec pers the graph.pl) I have essentially flatlining throughput at 0.  That
> | > doesn't seem right.  What am I missing?
> | 
> | Not sure. What's the output from stat? Does it really report throughput 
> | of 0 or is it just a problem with graph.pl?
> 
> Maybe it is graph.pl.  I let stat run for a bit and tee(1)'ed the result, see
> below.  Running is again right now. Latency sits steady at 190, then jumped
> to 2786, came back down again and now jumped to 8476 which is outside the
> graph. Now down again.

Tuning the for deterministic latencies is a delicate job. What HW setup 
are you running the example on?

> 
> Throughput always sits at 0-ish values in the chart, I guess it read 20k:
> 
> 1=20000 2=19999 3=48668 4=48684 l=174
> 1=20000 2=19999 3=48668 4=48684 l=174
> 1=20000 2=19999 3=48668 4=48684 l=174
> 1=20000 2=19999 3=48668 4=48684 l=174
> 1=20000 2=19999 3=48668 4=48684 l=174
> [...]

As far as I can say you've set message rate to 20000. Try changing the 
second command line parameter ("orders per second") when running gtw 
application. Note that when you exceed maximal throughput, latencies 
will go out of bounds as the messages will delay in queues.

Martin