1# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5"""
6This is a profiler class for the perf profiler in ChromeOS. It differs from
7the existing perf profiler in autotset by directly substituting the options
8passed to the initialize function into the "perf" command line. It allows one
9to specify which perf command to run and thus what type of profile to collect
10(e.g. "perf record" or "perf stat"). It also does not produce a perf report
11on the client (where there are no debug symbols) but instead copies
12the perf.data file back to the server for analysis.
13"""
14
15import os, signal, subprocess
16from autotest_lib.client.bin import profiler, os_dep
17from autotest_lib.client.common_lib import error
18
19
20class cros_perf(profiler.profiler):
21    version = 1
22
23    def initialize(self, options='-e cycles', profile_type='record'):
24        # The two supported options for profile_type are 'record' and 'stat'.
25        self.options = options
26        self.perf_bin = os_dep.command('perf')
27        self.profile_type = profile_type
28
29
30    def start(self, test):
31        if self.profile_type == 'record':
32            # perf record allows you to specify where to place the output.
33            # perf stat does not.
34            logfile = os.path.join(test.profdir, 'perf.data')
35            self.options += ' -o %s' % logfile
36
37        if self.profile_type == 'stat':
38            # Unfortunately we need to give perf stat a command or process even
39            # when running in system-wide mode.
40            self.options += ' -p 1'
41
42        outfile = os.path.join(test.profdir, 'perf.out')
43
44        cmd = ('exec %s %s -a %s > %s 2>&1' %
45               (self.perf_bin, self.profile_type, self.options, outfile))
46
47        self._process = subprocess.Popen(cmd, shell=True,
48                                         stderr=subprocess.STDOUT)
49
50
51    def stop(self, test):
52        ret_code = self._process.poll()
53        if ret_code is not None:
54            raise error.AutotestError('perf terminated early with return code: '
55                                      '%d. Please check your logs.' % ret_code)
56
57        self._process.send_signal(signal.SIGINT)
58        self._process.wait()
59