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1# Copyright 2016 Google Inc.
2#
3# Use of this source code is governed by a BSD-style license that can be
4# found in the LICENSE file.
5
6import time
7
8class Hardware:
9  """Locks down and monitors hardware for benchmarking.
10
11  This is a common base for classes that can control the specific hardware
12  we are running on. Its purpose is to lock the hardware into a constant
13  benchmarking mode for the duration of a 'with' block. e.g.:
14
15    with hardware:
16      run_benchmark()
17
18  While benchmarking, the caller must call sanity_check() frequently to verify
19  the hardware state has not changed.
20
21  """
22
23  def __init__(self):
24    self.warmup_time = 0
25
26  def __enter__(self):
27    return self
28
29  def __exit__(self, exception_type, exception_value, traceback):
30    pass
31
32  def filter_line(self, line):
33    """Returns False if the provided output line can be suppressed."""
34    return True
35
36  def sanity_check(self):
37    """Raises a HardwareException if any hardware state is not as expected."""
38    pass
39
40  def print_debug_diagnostics(self):
41    """Prints any info that may help improve or debug hardware monitoring."""
42    pass
43
44  def sleep(self, sleeptime):
45    """Puts the hardware into a resting state for a fixed amount of time."""
46    time.sleep(sleeptime)
47
48
49class HardwareException(Exception):
50  """Gets thrown when certain hardware state is not what we expect.
51
52  Generally this happens because of thermal conditions or other variables beyond
53  our control, and the appropriate course of action is to take a short nap
54  before resuming the benchmark.
55
56  """
57
58  def __init__(self, message, sleeptime=60):
59    Exception.__init__(self, message)
60    self.sleeptime = sleeptime
61
62
63class Expectation:
64  """Simple helper for checking the readings on hardware gauges."""
65  def __init__(self, value_type, min_value=None, max_value=None,
66               exact_value=None, name=None, sleeptime=60):
67    self.value_type = value_type
68    self.min_value = min_value
69    self.max_value = max_value
70    self.exact_value = exact_value
71    self.name = name
72    self.sleeptime = sleeptime
73
74  def check(self, stringvalue):
75    typedvalue = self.value_type(stringvalue)
76    if self.min_value is not None and typedvalue < self.min_value:
77       raise HardwareException("%s is too low (%s, min=%s)" %
78                               (self.name, stringvalue, str(self.min_value)),
79                               sleeptime=self.sleeptime)
80    if self.max_value is not None and typedvalue > self.max_value:
81       raise HardwareException("%s is too high (%s, max=%s)" %
82                               (self.name, stringvalue, str(self.max_value)),
83                               sleeptime=self.sleeptime)
84    if self.exact_value is not None and typedvalue != self.exact_value:
85       raise HardwareException("unexpected %s (%s, expected=%s)" %
86                               (self.name, stringvalue, str(self.exact_value)),
87                               sleeptime=self.sleeptime)
88
89  @staticmethod
90  def check_all(expectations, stringvalues):
91    if len(stringvalues) != len(expectations):
92      raise Exception("unexpected reading from hardware gauges "
93                      "(expected %i values):\n%s" %
94                      (len(expectations), '\n'.join(stringvalues)))
95
96    for value, expected in zip(stringvalues, expectations):
97      expected.check(value)
98