Add python perftests test runner.

scripts/perf_test_runner.py

+#!/usr/bin/python
+#
+# Copyright 2015 The ANGLE Project Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# perf_test_runner.py:
+#   Helper script for running and analyzing perftest results. Runs the
+#   tests in an infinite batch, printing out the mean and standard
+#   deviation of the population continuously.
+#
+
+import subprocess
+import sys
+import os
+
+# You might have to re-order these to find the specific version you want.
+perftests_paths = ['out/Release', 'build/Release_x64', 'build/Release_Win32']
+metric = 'score'
+
+scores = []
+
+# Danke to http://stackoverflow.com/a/27758326
+def mean(data):
+    """Return the sample arithmetic mean of data."""
+    n = len(data)
+    if n < 1:
+        raise ValueError('mean requires at least one data point')
+    return float(sum(data))/float(n) # in Python 2 use sum(data)/float(n)
+
+def _ss(data):
+    """Return sum of square deviations of sequence data."""
+    c = mean(data)
+    ss = sum((float(x)-c)**2 for x in data)
+    return ss
+
+def pstdev(data):
+    """Calculates the population standard deviation."""
+    n = len(data)
+    if n < 2:
+        raise ValueError('variance requires at least two data points')
+    ss = _ss(data)
+    pvar = ss/n # the population variance
+    return pvar**0.5
+
+def truncated_list(data, n):
+    """Compute a truncated list, n is truncation size"""
+    if len(data) < n * 2:
+        raise ValueError('list not large enough to truncate')
+    return sorted(data)[n:-n]
+
+def truncated_mean(data, n):
+    return mean(truncated_list(data, n))
+
+def truncated_stddev(data, n):
+    return pstdev(truncated_list(data, n))
+
+perftests_path = ""
+
+# TODO(jmadill): Linux binaries
+for path in perftests_paths:
+    perftests_path = os.path.join(path, 'angle_perftests.exe')
+    if os.path.exists(perftests_path):
+        break
+
+if not os.path.exists(perftests_path):
+    print("Cannot find angle_perftests.exe!")
+    sys.exit(1)
+
+test_name = "DrawCallPerfBenchmark.Run/d3d11_null"
+
+if len(sys.argv) >= 2:
+    test_name = sys.argv[1]
+
+# Infinite loop of running the tests.
+while True:
+    output = subprocess.check_output([perftests_path, '--gtest_filter=' + test_name])
+
+    start_index = output.find(metric + "=")
+    if start_index == -1:
+        print("Did not find test output")
+        sys.exit(1)
+
+    start_index += len(metric) + 2
+
+    end_index = output[start_index:].find(" ")
+    if end_index == -1:
+        print("Error parsing output")
+        sys.exit(2)
+
+    end_index += start_index
+
+    score = int(output[start_index:end_index])
+    sys.stdout.write("score: " + str(score))
+
+    scores.append(score)
+    sys.stdout.write(", mean: " + str(mean(scores)))
+
+    if (len(scores) > 1):
+        sys.stdout.write(", stddev: " + str(pstdev(scores)))
+
+    if (len(scores) > 7):
+        trucation_n = len(scores) >> 3
+        sys.stdout.write(", truncated mean: " + str(truncated_mean(scores, trucation_n)))
+        sys.stdout.write(", stddev: " + str(truncated_stddev(scores, trucation_n)))
+
+    print("")