Incorrect throughput being seen in report and differing PGL configs

[Dmitry Kurochkin]

Hi.

On Tue, 02 Aug 2011 14:51:09 +0100, Mohammed Rakhada <morakhad at cisco.com> wrote:
> Hello,
> 
> I am using Web Polygraph version 4.4.0 and running against a proxy
> server using 8 clients and 8 servers. After the report is run I see the
> following data.
> 
> 
> label: Tue Aug 2 13:52:51 BST 2011
> throughput: 4196.00xact/sec or 608.43Mbits/sec
> response time: 49msec mean
> hit ratios: 18.86% DHR and 6.88% BHR
> unique URLs: 820565xact (35.40% recurrence)
> errors: 0.00% (8xact out of 1270224xact)
> duration: 5.05min
> start time: Tue, 02 Aug 2011 12:53:18 GMT
> workload: available
> Polygraph version: 4.4.0
> reporter version: 4.4.0
> 
> however when I am looking at the switch statistics the number reported
> is much lower (360Mbits/sec)
> 
> Could you clarify what the throughput value actually relates to?
> 

Throughput on the index page of HTML report is client side reply
throughput, i.e. (size of all replies clients received) / duration).  It
does not include requests or replies sent by servers.

I am not sure why you see lower throughput stats on the switch.  You may
get wrong stats in reporter if you specify a single log multiple times
on the command line.  I do not think it is likely, but this may be a bug
in Polygraph reporter or client.

If you believe Polygraph stats are wrong, I recommend you start with
checking that throughput in reporter is calculated correctly from binary
logs.  Make sure you do not specify any log twice in reporter
parameters.  Try generating report for a single log: throughput for
multiple logs should be equal to sum of all throughputs from each log.

You may also send us Polygraph binary logs for investigation.

> I am also seeing the following message when trying to run the
> polygraph-reporter. Could you help so that I can avoid this error?
> 
> PGL configuration in /opt/stress/scripts/tmp/sss-101-strs_1312291541.log
> differs from the one
> in /opt/stress/scripts/tmp/sss-103-strs_1312291541.log
> 
> All the configs are identical apart from the "use" line at the bottom
> which I generate to pair up my servers and clients. The attached file
> 192.168.29.101.polygraph.pg is an example of this line. Each pair of
> server / client will have the same line but the next pair will have a
> different line.
> 

To get rid of the warning you should use the same workload for all
Polygraph client and server processes.  It should be simple for your
current workload: use a single PGL Robot and Server with addresses,
origins, and http_proxies set to list of all addresses you need.  E.g.:

  Robot R = {
    ...
    origins = [ all server addresses ];
    addresses = [ all client addresses ];
    http_proxies = [ all HTTP proxy addresses ];
  };

When Polygraph client (server) starts, it checks network interfaces
configured on the host and starts only those Robots (Servers) that use
locally configured address.  So when you run such workload on different
hosts, agents with different addresses would be started, which is what
you want, I guess.  This would also allow result in all Robots making
requests to all Servers (with your current workload, Robots running on a
given hosts always make requests to a single Server though a single HTTP
proxy).

Note: you may copy PGL objects to avoid setting the same properties
multiple times, e.g.:

  Robot Base = {
    // common settings
    ...
  };

  Robot R1 = Base;
  R1.req_types = ...; // set R1-specific properties

Regards,
  Dmitry

> Attached are my polygraph files to help you understand my setup.
> 
> Please let me know if you require further information or clarification.
> 
> Thanks in advance.
> 
> Mohammed Rakhada
> Systems Administrator
> Cisco Ltd