[PATCH 5/7] Netperf: add support for confidence (-I option)

[Ondrej Lichtner]

From: Ondrej Lichtner <olichtne(a)redhat.com&gt;

This patch adds support for the confidence feature of Netperf. You can
start using this feature by defining the 'confidence' option of the test
module. The format is identical to what is accepted by the netperf
client so:
lvl[,intvl]
where:
  lvl     is either 95 or 99 and specifies the confidence level
  intlvl  is the width of the confidence interval as a percentage

You can further configure the min and max number of runs by specifying
the -i option using the 'netperf_opts' test module option.

The resulting measured confidence is used to compute the deviation of
the result and creating the interval that will be used for comparison
against a threshold.

Signed-off-by: Ondrej Lichtner <olichtne(a)redhat.com&gt;
---
 test_modules/Netperf.py | 44 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 42 insertions(+), 2 deletions(-)

diff --git a/test_modules/Netperf.py b/test_modules/Netperf.py
index a538520..eebf834 100644
--- a/test_modules/Netperf.py
+++ b/test_modules/Netperf.py
@@ -31,10 +31,15 @@ class Netperf(TestGeneric):
         self._duration = self.get_opt("duration")
         self._port = self.get_opt("port")
         self._testname = self.get_opt("testname",
default="TCP_STREAM")
+        self._confidence = self.get_opt("confidence")
         self._bind = self.get_opt("bind", opt_type="addr")
         self._family = self.get_opt("family")
 
         self._runs = self.get_opt("runs", default=1)
+        if self._runs > 1 and self._confidence is not None:
+            logging.warning("Ignoring 'runs' because 'confidence'
"\
+                            "was specified.")
+            self._runs = 1
 
         self._threshold = self._parse_threshold(self.get_opt("threshold"))
         self._threshold_deviation = self._parse_threshold(
@@ -78,6 +83,12 @@ class Netperf(TestGeneric):
                     "can use other tests, but test result may not be
correct.")
                 cmd += " -t %s" % self._testname
 
+            if self._confidence is not None:
+                """
+                confidence level that Netperf should try to achieve
+                """
+                cmd += " -I %s" % self._confidence
+
             if self._netperf_opts is not None:
                 """
                 custom options for netperf
@@ -129,8 +140,34 @@ class Netperf(TestGeneric):
         else:
             rate_in_kb = float(r2.group(1))
 
-        return {"rate": rate_in_kb*1000,
-                "unit": "bps"}
+        if self._confidence is not None:
+            confidence = self._parse_confidence(output)
+            return {"rate": rate_in_kb*1000,
+                    "unit": "bps",
+                    "confidence": confidence}
+        else:
+            return {"rate": rate_in_kb*1000,
+                    "unit": "bps"}
+
+    def _parse_confidence(self, output):
+        normal_pattern = r'\+/-(\d+\.\d*)% @ (\d+)% conf\.'
+        warning_pattern = r'!!! Confidence intervals: Throughput\s+:
(\d+\.\d*)%'
+        normal_confidence = re.search(normal_pattern, output)
+        warning_confidence = re.search(warning_pattern, output)
+
+        if normal_confidence is None:
+            logging.error("Failed to parse confidence!!")
+            return (0, 0.0)
+
+        if warning_confidence is None:
+            real_confidence = (float(normal_confidence.group(2)),
+                               float(normal_confidence.group(1)))
+        else:
+            real_confidence = (float(normal_confidence.group(2)),
+                               float(warning_confidence.group(1)))
+
+        return real_confidence
+
 
     def _parse_threshold(self, threshold):
         if threshold is None:
@@ -224,6 +261,9 @@ class Netperf(TestGeneric):
 
         if len(rates) > 1:
             rate_deviation = std_deviation(rates)
+        elif len(rates) == 1 and self._confidence is not None:
+            result = results[0]
+            rate_deviation = rate * (result["confidence"][1] / 100)
         else:
             rate_deviation = 0.0
 
-- 
2.4.6