CSIT-1420: Split methodology section to more files

[csit.git] / docs / report / introduction / methodology_trex_traffic_generator.rst

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+TRex Traffic Generator
+----------------------
+
+Usage
+~~~~~
+
+`TRex traffic generator <https://wiki.fd.io/view/TRex>`_ is used for all
+CSIT performance tests. TRex stateless mode is used to measure NDR and
+PDR throughputs using binary search (NDR and PDR discovery tests) and
+for quick checks of DUT performance against the reference NDRs (NDR
+check tests) for specific configuration.
+
+TRex is installed and run on the TG compute node. The typical procedure
+is:
+
+- If the TRex is not already installed on TG, it is installed in the
+  suite setup phase - see `TRex intallation`_.
+- TRex configuration is set in its configuration file
+  ::
+
+  /etc/trex_cfg.yaml
+
+- TRex is started in the background mode
+  ::
+
+  $ sh -c 'cd <t-rex-install-dir>/scripts/ && sudo nohup ./t-rex-64 -i -c 7 --iom 0 > /tmp/trex.log 2>&1 &' > /dev/null
+
+- There are traffic streams dynamically prepared for each test, based on traffic
+  profiles. The traffic is sent and the statistics obtained using
+  :command:`trex_stl_lib.api.STLClient`.
+
+Measuring Packet Loss
+~~~~~~~~~~~~~~~~~~~~~
+
+Following sequence is followed to measure packet loss:
+
+- Create an instance of STLClient.
+- Connect to the client.
+- Add all streams.
+- Clear statistics.
+- Send the traffic for defined time.
+- Get the statistics.
+
+If there is a warm-up phase required, the traffic is sent also before
+test and the statistics are ignored.
+
+Measuring Latency
+~~~~~~~~~~~~~~~~~
+
+If measurement of latency is requested, two more packet streams are
+created (one for each direction) with TRex flow_stats parameter set to
+STLFlowLatencyStats. In that case, returned statistics will also include
+min/avg/max latency values.