1# Copyright (c) 2012 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
5import hashlib, logging, multiprocessing, os, re, time
6from autotest_lib.client.bin import test, utils
7from autotest_lib.client.common_lib import error
8from autotest_lib.client.cros import sys_power
9
10SUSPEND_BURN_SECONDS = 10
11RESUME_BURN_SECONDS = 5
12MIN_CPU_USAGE = .95
13
14PROC_STAT_CPU_FIELDS = ['user', 'nice', 'system', 'idle', 'iowait', 'irq',
15                        'softirq', 'steal', 'guest', 'guest_nice']
16PROC_STAT_CPU_IDLE_FIELDS = ['idle', 'iowait']
17
18SYSFS_CPUQUIET_ENABLE = '/sys/devices/system/cpu/cpuquiet/tegra_cpuquiet/enable'
19
20def cpu_stress():
21    sha512_hash = open('/dev/urandom', 'r').read(64)
22    while True:
23        sha512_hash = hashlib.sha512(sha512_hash).digest()
24
25
26def get_system_times():
27    proc_stat = utils.read_file('/proc/stat')
28    for line in proc_stat.split('\n'):
29        if line.startswith('cpu '):
30            times = line[4:].strip().split(' ')
31            times = [int(jiffies) for jiffies in times]
32            return dict(zip(PROC_STAT_CPU_FIELDS, times))
33
34
35def get_avg_cpu_usage(pre_times, post_times):
36    diff_times = {}
37
38    for field in PROC_STAT_CPU_FIELDS:
39        diff_times[field] = post_times[field] - pre_times[field]
40
41    idle_time = sum(diff_times[field] for field in PROC_STAT_CPU_IDLE_FIELDS)
42    total_time = sum(diff_times[field] for field in PROC_STAT_CPU_FIELDS)
43
44    return float(total_time - idle_time) / total_time
45
46
47def sleep_and_measure_cpu(sleep_seconds):
48    pre_times = get_system_times()
49    time.sleep(sleep_seconds)
50    post_times = get_system_times()
51
52    avg_cpu_usage = get_avg_cpu_usage(pre_times, post_times)
53    logging.info('average CPU utilization, last %ds: %s%%',
54                 sleep_seconds, avg_cpu_usage * 100.)
55    return avg_cpu_usage
56
57
58class power_HotCPUSuspend(test.test):
59    """Suspend the system with 100% CPU usage."""
60
61    version = 1
62
63    def initialize(self):
64        # Store the setting if the system has CPUQuiet feature
65        if os.path.exists(SYSFS_CPUQUIET_ENABLE):
66            self.is_cpuquiet_enabled = utils.read_file(SYSFS_CPUQUIET_ENABLE)
67            utils.write_one_line(SYSFS_CPUQUIET_ENABLE, '0')
68
69    def run_once(self):
70        # create processs pool with enough workers to spin all CPUs
71        cpus = multiprocessing.cpu_count()
72        logging.info('found %d cpus', cpus)
73        workers = max(16, cpus * 2)
74        pool = multiprocessing.Pool(workers)
75
76        try:
77            # fill all CPUs with a spinning task
78            logging.info('starting %d workers', workers)
79            results = [pool.apply_async(cpu_stress) for _ in xrange(workers)]
80
81            # wait for things to settle
82            logging.info('spinning for %d seconds', SUSPEND_BURN_SECONDS)
83            if sleep_and_measure_cpu(SUSPEND_BURN_SECONDS) < MIN_CPU_USAGE:
84                # There should be no idle time accounted while we're spinning.
85                raise error.TestError('unexpected CPU idle time while spinning')
86
87            # go to suspend
88            sys_power.kernel_suspend(10)
89
90            # keep spinning after userland resumes
91            logging.info('spinning for %d more seconds', RESUME_BURN_SECONDS)
92            if sleep_and_measure_cpu(RESUME_BURN_SECONDS) < MIN_CPU_USAGE:
93                # There should be no idle time accounted while we're spinning.
94                raise error.TestError('unexpected CPU idle time after resume')
95
96            # check workers: if computation completed, something is wrong
97            for result in results:
98                if result.ready():
99                    logging.error('worker finished: %s', result.get())
100                    raise error.TestError('worker terminated!')
101
102        finally:
103            # kill off the workers
104            logging.info('killing %d workers', workers)
105            pool.terminate()
106
107    def cleanup(self):
108        # Restore the original setting if system has CPUQuiet feature
109        if os.path.exists(SYSFS_CPUQUIET_ENABLE):
110            utils.open_write_close(
111                SYSFS_CPUQUIET_ENABLE, self.is_cpuquiet_enabled)
112