Add antagonist processes to run_tests.py arsenal

These are processes consume CPU for the purpose of slowing down tests, allowing more timing related issues to be exposed.

tools/run_tests/antagonist.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""This is used by run_tests.py to create cpu load on a machine"""
+
+while True:
+	pass

tools/run_tests/run_tests.py

@@ -40,6 +40,7 @@ import re
 import sys
 import time
 import platform
+import subprocess
 
 import jobset
 import watch_dirs
@@ -350,6 +351,7 @@ argp.add_argument('-l', '--language',
                   choices=sorted(_LANGUAGES.keys()),
                   nargs='+',
                   default=sorted(_LANGUAGES.keys()))
+argp.add_argument('-a', '--antagonists', default=0, type=int)
 args = argp.parse_args()
 
 # grab config
@@ -444,14 +446,21 @@ def _build_and_run(check_cancelled, newline_on_success, travis, cache):
                     newline_on_success=newline_on_success, travis=travis):
     return 1
 
-  # run all the tests
-  all_runs = itertools.chain.from_iterable(
-      itertools.repeat(one_run, runs_per_test))
-  if not jobset.run(all_runs, check_cancelled,
-                    newline_on_success=newline_on_success, travis=travis,
-                    maxjobs=min(args.jobs, min(c.maxjobs for c in run_configs)),
-                    cache=cache):
-    return 2
+  # start antagonists
+  antagonists = [subprocess.Popen(['tools/run_tests/antagonist.py']) 
+                 for _ in range(0, args.antagonists)]
+  try:
+    # run all the tests
+    all_runs = itertools.chain.from_iterable(
+        itertools.repeat(one_run, runs_per_test))
+    if not jobset.run(all_runs, check_cancelled,
+                      newline_on_success=newline_on_success, travis=travis,
+                      maxjobs=min(args.jobs, min(c.maxjobs for c in run_configs)),
+                      cache=cache):
+      return 2
+  finally:
+    for antagonist in antagonists:
+      antagonist.kill()
 
   return 0