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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 
      7 import os
      8 
      9 from autotest_lib.client.bin import utils
     10 
     11 
     12 class SystemFacadeNativeError(Exception):
     13     """Error in SystemFacadeNative."""
     14     pass
     15 
     16 
     17 class 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             'sched'
     29             ]
     30 
     31     def set_scaling_governor_mode(self, index, mode):
     32         """Set mode of CPU scaling governor on one CPU.
     33 
     34         @param index: CPU index starting from 0.
     35 
     36         @param mode: Mode of scaling governor, accept 'interactive' or
     37                      'performance'.
     38 
     39         @returns: The original mode.
     40 
     41         """
     42         if mode not in self.SCALING_GOVERNOR_MODES:
     43             raise SystemFacadeNativeError('mode %s is invalid' % mode)
     44 
     45         governor_path = os.path.join(
     46                 '/sys/devices/system/cpu/cpu%d' % index,
     47                 'cpufreq/scaling_governor')
     48         if not os.path.exists(governor_path):
     49             raise SystemFacadeNativeError(
     50                     'scaling governor of CPU %d is not available' % index)
     51 
     52         original_mode = utils.read_one_line(governor_path)
     53         utils.open_write_close(governor_path, mode)
     54 
     55         return original_mode
     56 
     57 
     58     def get_cpu_usage(self):
     59         """Returns machine's CPU usage.
     60 
     61         Returns:
     62             A dictionary with 'user', 'nice', 'system' and 'idle' values.
     63             Sample dictionary:
     64             {
     65                 'user': 254544,
     66                 'nice': 9,
     67                 'system': 254768,
     68                 'idle': 2859878,
     69             }
     70         """
     71         return utils.get_cpu_usage()
     72 
     73 
     74     def compute_active_cpu_time(self, cpu_usage_start, cpu_usage_end):
     75         """Computes the fraction of CPU time spent non-idling.
     76 
     77         This function should be invoked using before/after values from calls to
     78         get_cpu_usage().
     79         """
     80         return utils.compute_active_cpu_time(cpu_usage_start,
     81                                                   cpu_usage_end)
     82 
     83 
     84     def get_mem_total(self):
     85         """Returns the total memory available in the system in MBytes."""
     86         return utils.get_mem_total()
     87 
     88 
     89     def get_mem_free(self):
     90         """Returns the currently free memory in the system in MBytes."""
     91         return utils.get_mem_free()
     92 
     93     def get_mem_free_plus_buffers_and_cached(self):
     94         """
     95         Returns the free memory in MBytes, counting buffers and cached as free.
     96 
     97         This is most often the most interesting number since buffers and cached
     98         memory can be reclaimed on demand. Note however, that there are cases
     99         where this as misleading as well, for example used tmpfs space
    100         count as Cached but can not be reclaimed on demand.
    101         See https://www.kernel.org/doc/Documentation/filesystems/tmpfs.txt.
    102         """
    103         return utils.get_mem_free_plus_buffers_and_cached()
    104 
    105     def get_ec_temperatures(self):
    106         """Uses ectool to return a list of all sensor temperatures in Celsius.
    107         """
    108         return utils.get_ec_temperatures()
    109 
    110     def get_current_temperature_max(self):
    111         """
    112         Returns the highest reported board temperature (all sensors) in Celsius.
    113         """
    114         return utils.get_current_temperature_max()
    115 
    116     def get_current_board(self):
    117         """Returns the current device board name."""
    118         return utils.get_current_board()
    119 
    120 
    121     def get_chromeos_release_version(self):
    122         """Returns chromeos version in device under test as string. None on
    123         fail.
    124         """
    125         return utils.get_chromeos_release_version()
    126 
    127     def get_num_allocated_file_handles(self):
    128         """
    129         Returns the number of currently allocated file handles.
    130         """
    131         return utils.get_num_allocated_file_handles()
    132