Initiate the script that takes a snapshot of CPU usage

scripts/slave/recipe_modules/auto_bisect/resources/cpu_usage.py

+#!/usr/bin/python
+# 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.
+
+"""Prints out the most active processes running in the background.
+
+Example usage:
+  ./cpu_usage.py --nproc==[THE NUMBER OF PROCESSES TO PRINT OUT] 
+"""
+
+
+import argparse
+import json
+import platform
+import subprocess
+import sys
+
+LINUX_START_LINE_NUM = 7
+WINDOWS_START_LINE_NUM = 3
+
+def _parse_line(line):
+    """Parses a line from top output
+
+      Args:
+        line(str): a line from top output that contains the
+        information of a process
+
+      Returns:
+        An dictionary with useful information about the process
+
+    """
+    token_list = line.strip().split()
+    if platform.system() == "Windows":
+        process_object = {'pid':token_list[6],
+                          'pCPU':token_list[5],
+                          'command':token_list[7]}
+    else:
+        process_object = {'pid':token_list[0], 'user':token_list[1],
+                          'pCPU':token_list[8], 'pMEM':token_list[9],
+                          'command':token_list[11]}
+    return process_object
+
+def _get_top_processes(n):
+    """Fetches the top processes returned by top command
+
+      Args:
+        n(int): the number of processes to get
+
+      Returns:
+      A list of dictionaries, each representing one of the top processes
+
+    """
+    if platform.system() == "Windows":
+        processes = subprocess.check_output('powershell "ps | sort -desc cpu"',
+                                            shell=True).split('\n')
+        top_processes = processes[WINDOWS_START_LINE_NUM: \

[RobertoCN, 2016/06/03 18:01:42]

Backslash not necessary to break the line here because of the open brackets.

+                                    WINDOWS_START_LINE_NUM+n]

[RobertoCN, 2016/06/03 18:01:42]

spaces around the + operator, align with the previous line.

+    else:
+        processes = subprocess.check_output(["top","-n 1","-b"]).split('\n')
+        top_processes = processes[LINUX_START_LINE_NUM: \

[RobertoCN, 2016/06/03 18:01:42]

same as before

+                                    LINUX_START_LINE_NUM+n]
+    parsed_top_processes = [_parse_line(process) \
+                            for process in top_processes]
+    return parsed_top_processes
+
+
+def main():
+    parser = argparse.ArgumentParser(description=\

[RobertoCN, 2016/06/03 18:01:42]

Maybe it would be easier to read to break the line after opening parenthesis,
backslash not necessary in this case.

+                                        'Take a snapshot of CPU usage.')
+    parser.add_argument('--nproc', dest='nproc', default=10,
+                    help='the number of processes to display')
+    args = parser.parse_args()
+    top_processes = _get_top_processes(int(args.nproc))
+    print(json.dumps(top_processes))
+    return 0
+
+if __name__ == "__main__":
+    main()