[zeromq-dev] ZMQ_RATE

[Emmanuel TAUREL]

On 03/10/2011 17:53, Steven McCoy wrote:
> On 3 October 2011 11:18, Emmanuel TAUREL <taurel at esrf.fr 
> <mailto:taurel at esrf.fr>> wrote:
>
>     On 03/10/2011 17:02, Steven McCoy wrote:
>>     On 3 October 2011 10:19, Emmanuel TAUREL <taurel at esrf.fr
>>     <mailto:taurel at esrf.fr>> wrote:
>>
>>         Hello all,
>>
>>         I am experimenting PUB/SUB sockets with PGM protocol.
>>         I am actually using with the ZMQ_RATE socket option.
>>         My understanding of this parameter was that it is the maximum
>>         rate for
>>         sending/receiving data and thus limits the network bandwidth
>>         used by PGM.
>>         In my test, the publisher sends messages as fast as it can.
>>         I have tried different value for the ZMQ_RATE parameter: 100
>>         which means
>>         100 kbits/sec (the default) and 80000 which means 80Mbit/sec.
>>         I capture network packets using wireshark. When I look at its
>>         IO graph
>>         after the capture, there is no difference between the two runs.
>>         During the PGM transmission, I always have a network usage
>>         close to 100
>>         Mbit/sec which is my network bandwidth between the pub and
>>         sub hosts.
>>
>>         Where is my error?
>>         Do I have to understand that ZMQ_RATE limits the data rate in the
>>         process but not on the network (meaning buffering required in
>>         case of
>>         slow ZMQ_RATE)?
>>
>>
>>     Correct but the differences are going to be only latent.
>>
>>     The default for ZMQ_RATE is now 40*1000, 40mbit/s, because you
>>     cannot really do any testing with 100kbit/s as it is way too
>>     slow.  This does suggest you are on an older version and you may
>>     wish to retry with at least 2.1.9.
>>
>>     You can compare with the local_thr and remote_thr performance
>>     test programs which work correctly.
>>
>>     There may be a problem with timer accuracy on your platform, you
>>     may try setting the environment variable PGM_TIMER to
>>     GETTIMEOFDAY, TSC, or CLOCK_GETTIME for different methods:
>>
>>     http://code.google.com/p/openpgm/wiki/OpenPgmCReferenceRunWithTheseCapabilities
>>
>
>     Thank's for your answer.
>     I am using zmq 3.
>
>
> So this might be a regression on setting the rate limit on the PGM 
> socket.  I would suggest comparing operation with version 2.  I'm only 
> looking at v2 for bug fixes and v4 for enhancements so additional 
> awareness is required for the v3 branch.
>

I am sorry but I am lost. In our application, we would like to use 
either TCP transport either PGM transport.
With ZMQ 3, we have the nice event subscription feature and this is why 
we are using it.
Do you mean that PGM is not supported with ZMQ 3?

Regards

Emmanuel

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