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1# Copyright 2015 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"""Facade to access the system-related functionality."""
6
7import os
8
9from autotest_lib.client.bin import utils, site_utils
10
11
12class SystemFacadeNativeError(Exception):
13    """Error in SystemFacadeNative."""
14    pass
15
16
17class SystemFacadeNative(object):
18    """Facede to access the system-related functionality.
19
20    The methods inside this class only accept Python native types.
21
22    """
23    SCALING_GOVERNOR_MODES = [
24            'interactive',
25            'performance',
26            'ondemand',
27            'powersave',
28            ]
29
30    def set_scaling_governor_mode(self, index, mode):
31        """Set mode of CPU scaling governor on one CPU.
32
33        @param index: CPU index starting from 0.
34
35        @param mode: Mode of scaling governor, accept 'interactive' or
36                     'performance'.
37
38        @returns: The original mode.
39
40        """
41        if mode not in self.SCALING_GOVERNOR_MODES:
42            raise SystemFacadeNativeError('mode %s is invalid' % mode)
43
44        governor_path = os.path.join(
45                '/sys/devices/system/cpu/cpu%d' % index,
46                'cpufreq/scaling_governor')
47        if not os.path.exists(governor_path):
48            raise SystemFacadeNativeError(
49                    'scaling governor of CPU %d is not available' % index)
50
51        original_mode = utils.read_one_line(governor_path)
52        utils.open_write_close(governor_path, mode)
53
54        return original_mode
55
56
57    def get_cpu_usage(self):
58        """Returns machine's CPU usage.
59
60        Returns:
61            A dictionary with 'user', 'nice', 'system' and 'idle' values.
62            Sample dictionary:
63            {
64                'user': 254544,
65                'nice': 9,
66                'system': 254768,
67                'idle': 2859878,
68            }
69        """
70        return site_utils.get_cpu_usage()
71
72
73    def compute_active_cpu_time(self, cpu_usage_start, cpu_usage_end):
74        """Computes the fraction of CPU time spent non-idling.
75
76        This function should be invoked using before/after values from calls to
77        get_cpu_usage().
78        """
79        return site_utils.compute_active_cpu_time(cpu_usage_start,
80                                                  cpu_usage_end)
81
82
83    def get_mem_total(self):
84        """Returns the total memory available in the system in MBytes."""
85        return site_utils.get_mem_total()
86
87
88    def get_mem_free(self):
89        """Returns the currently free memory in the system in MBytes."""
90        return site_utils.get_mem_free()
91
92
93    def get_ec_temperatures(self):
94        """Uses ectool to return a list of all sensor temperatures in Celsius.
95        """
96        return site_utils.get_ec_temperatures()
97
98
99    def get_current_board(self):
100        """Returns the current device board name."""
101        return utils.get_current_board()
102
103
104    def get_chromeos_release_version(self):
105        """Returns chromeos version in device under test as string. None on
106        fail.
107        """
108        return utils.get_chromeos_release_version()
109