trex: RFC2544 Throughput bugfixing

Changes introduced by patch:
* Ensure that correct results with given lossreate are returned
* Add threshold value to specify the accurancy of RFC2544 Throughput
  measurement. Default value is 0.05.

JIRA: VSPERF-530

Change-Id: I8148deba9039c3a0feb6394d6671aa10c5afaf0a
Signed-off-by: Martin Goldammer <martin.goldammer6@gmail.com>
Reviewed-by: Martin Klozik <martinx.klozik@intel.com>
Reviewed-by: Al Morton <acmorton@att.com>
Reviewed-by: Christian Trautman <ctrautma@redhat.com>
Reviewed-by: Trevor Cooper <trevor.cooper@intel.com>

3 files changed, 60 insertions, 13 deletions

diff --git a/conf/03_traffic.conf b/conf/03_traffic.conf
index 179ff3e2..5f6d791c 100644
--- a/conf/03_traffic.conf
+++ b/conf/03_traffic.conf
@@ -430,6 +430,10 @@ TRAFFICGEN_TREX_USER = ''
 TRAFFICGEN_TREX_BASE_DIR = ''
 TRAFFICGEN_TREX_PORT1 = ''
 TRAFFICGEN_TREX_PORT2 = ''
+# RFC2544 Throughput execution will end after threshold below is reached.
+# It defines maximal difference between frame rate of successful (i.e. defined
+# frameloss reached) and unsuccessful (i.e. frameloss exceeded) iterations.
+TRAFFICGEN_TREX_RFC2544_TPUT_THRESHOLD = 0.05
 # Latency statistics are collected by separate stream created for each interface.
 # Parameter below defines frequency of packets used for latency measurement in PPS.
 # Value 0 will disable latency specific streams.
diff --git a/docs/testing/user/configguide/trafficgen.rst b/docs/testing/user/configguide/trafficgen.rst
index 3c827f38..7c14c55d 100644
--- a/docs/testing/user/configguide/trafficgen.rst
+++ b/docs/testing/user/configguide/trafficgen.rst
@@ -810,3 +810,14 @@ Example of this configuration is in conf/03_traffic.conf or conf/10_custom.conf.
 
 TRAFFICGEN_TREX_USER has to have sudo permission and passwordless access.
 TRAFFICGEN_TREX_BASE_DIR is the place, where is stored 't-rex-64' file.
+
+It is possible to specify the accurancy of RFC2544 Throughput measurement.
+Threshold below defines maximal difference between frame rate of successful
+(i.e. defined frameloss was reached) and unsuccessful (i.e. frameloss was
+exceeded) iterations.
+
+Default value of this parameter is defined in conf/03_traffic.conf as follows:
+
+.. code-block:: console
+
+    TRAFFICGEN_TREX_RFC2544_TPUT_THRESHOLD = ''
diff --git a/tools/pkt_gen/trex/trex.py b/tools/pkt_gen/trex/trex.py
index e8ed42f1..7cdeec9c 100644
--- a/tools/pkt_gen/trex/trex.py
+++ b/tools/pkt_gen/trex/trex.py
@@ -30,6 +30,32 @@ from tools.pkt_gen.trafficgen.trafficgen import ITrafficGenerator
 sys.path.append(settings.getValue('PATHS')['trafficgen']['trex']['src']['path'])
 from trex_stl_lib.api import *
 
+_EMPTY_STATS = {
+    'global': {'bw_per_core': 0.0,
+               'cpu_util': 0.0,
+               'queue_full': 0.0,
+               'rx_bps': 0.0,
+               'rx_cpu_util': 0.0,
+               'rx_drop_bps': 0.0,
+               'rx_pps': 0.0,
+               'tx_bps': 0.0,
+               'tx_pps': 0.0,},
+    'latency': {},
+    'total': {'ibytes': 0.0,
+              'ierrors': 0.0,
+              'ipackets': 0.0,
+              'obytes': 0.0,
+              'oerrors': 0.0,
+              'opackets': 0.0,
+              'rx_bps': 0.0,
+              'rx_bps_L1': 0.0,
+              'rx_pps': 0.0,
+              'rx_util': 0.0,
+              'tx_bps': 0.0,
+              'tx_bps_L1': 0.0,
+              'tx_pps': 0.0,
+              'tx_util': 0.0,}}
+
 class Trex(ITrafficGenerator):
     """Trex Traffic generator wrapper."""
     _logger = logging.getLogger(__name__)
@@ -213,13 +239,15 @@ class Trex(ITrafficGenerator):
         result[ResultsConstants.TX_RATE_PERCENT] = 'Unknown'
 
         result[ResultsConstants.THROUGHPUT_RX_PERCENT] = 'Unknown'
+        if stats["total"]["opackets"]:
+            result[ResultsConstants.FRAME_LOSS_PERCENT] = (
+                '{:.3f}'.format(
+                    float((stats["total"]["opackets"] - stats["total"]["ipackets"]) * 100 /
+                          stats["total"]["opackets"])))
+        else:
+            result[ResultsConstants.FRAME_LOSS_PERCENT] = 100
 
-        result[ResultsConstants.FRAME_LOSS_PERCENT] = (
-            '{:.3f}'.format(
-                float((stats["total"]["opackets"] - stats["total"]["ipackets"]) * 100 /
-                      stats["total"]["opackets"])))
-
-        if settings.getValue('TRAFFICGEN_TREX_LATENCY_PPS') > 0:
+        if settings.getValue('TRAFFICGEN_TREX_LATENCY_PPS') > 0 and stats['latency']:
             result[ResultsConstants.MIN_LATENCY_NS] = (
                 '{:.3f}'.format(
                     (float(min(stats["latency"][0]["latency"]["total_min"],
@@ -272,9 +300,11 @@ class Trex(ITrafficGenerator):
         """
         self._logger.info("In Trex send_rfc2544_throughput method")
         self._params.clear()
+        threshold = settings.getValue('TRAFFICGEN_TREX_RFC2544_TPUT_THRESHOLD')
         test_lossrate = 0
         left = 0
-        num_test = 1
+        iteration = 1
+        stats_ok = _EMPTY_STATS
         self._params['traffic'] = self.traffic_defaults.copy()
         if traffic:
             self._params['traffic'] = merge_spec(
@@ -284,15 +314,16 @@ class Trex(ITrafficGenerator):
         right = traffic['frame_rate']
         center = traffic['frame_rate']
 
-        # execute 10 iterations to find out best tput with 0% packet loss
-        # unless 0% packet loss is detected for initial frame_rate
-        while num_test <= 10:
+        # Loops until the preconfigured difference between frame rate
+        # of successful and unsuccessful iterations is reached
+        while (right - left) > threshold:
             test_lossrate = ((stats["total"]["opackets"] - stats["total"]
                               ["ipackets"]) * 100) / stats["total"]["opackets"]
             self._logger.debug("Iteration: %s, frame rate: %s, throughput_rx_fps: %s, frame_loss_percent: %s",
-                               num_test, "{:.3f}".format(new_params['frame_rate']), stats['total']['rx_pps'],
+                               iteration, "{:.3f}".format(new_params['frame_rate']), stats['total']['rx_pps'],
                                "{:.3f}".format(test_lossrate))
             if test_lossrate == 0.0 and new_params['frame_rate'] == traffic['frame_rate']:
+                stats_ok = copy.deepcopy(stats)
                 break
             elif test_lossrate > lossrate:
                 right = center
@@ -301,13 +332,14 @@ class Trex(ITrafficGenerator):
                 new_params['frame_rate'] = center
                 stats = self.generate_traffic(new_params, duration)
             else:
+                stats_ok = copy.deepcopy(stats)
                 left = center
                 center = (left+right) / 2
                 new_params = copy.deepcopy(traffic)
                 new_params['frame_rate'] = center
                 stats = self.generate_traffic(new_params, duration)
-            num_test += 1
-        return self.calculate_results(stats)
+            iteration += 1
+        return self.calculate_results(stats_ok)
 
     def start_rfc2544_throughput(self, traffic=None, tests=1, duration=60,
                                  lossrate=0.0):