Iteratively increase sample size for good/bad classification.

scripts/slave/recipe_modules/bisect_tester/perf_test.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import os
 import re
 import time
 
 from . import parse_metric
 
@@ skipping 75 matching lines @@
   output_for_all_runs = []
   temp_dir = None
   repeat_cnt = test_config['repeat_count']
 
   command = test_config['command']
   use_chartjson = bool('chartjson' in command)
   is_telemetry = _is_telemetry_command(command)
   start_time = time.time()
   for i in range(repeat_cnt):
     elapsed_minutes = (time.time() - start_time) / 60.0
-    if elapsed_minutes >= limit:  # pragma: no cover
+    # A limit of 0 means 'no timeout set'.
+    if limit and elapsed_minutes >= limit:  # pragma: no cover
       break
     if is_telemetry:
       if i == 0 and kwargs.get('reset_on_first_run'):
         command += ' --reset-results'
       if i == repeat_cnt - 1 and kwargs.get('upload_on_last_run'):
         command += ' --upload-results'
       if kwargs.get('results_label'):
         command += ' --results-label=%s' % kwargs.get('results_label')
     if use_chartjson:  # pragma: no cover
       temp_dir = api.m.path.mkdtemp('perf-test-output')
@@ skipping 89 matching lines @@
         command_parts,
         stdout=stdout,
         stderr=stderr)
     step_result.presentation.logs['Captured Output'] = (
         step_result.stdout or '').splitlines()
   except api.m.step.StepFailure as sf:
     sf.result.presentation.logs['Failure Output'] = (
         sf.result.stdout or '').splitlines()
     return sf.result.stdout, sf.result.stderr, sf.result.retcode
   return step_result.stdout, step_result.stderr, step_result.retcode