AppPkg/Applications/Python/Python-2.7.2/Tools/pybench/systimes.py

   1 #!/usr/bin/env python
   2
   3 """ systimes() user and system timer implementations for use by
   4     pybench.
   5
   6     This module implements various different strategies for measuring
   7     performance timings. It tries to choose the best available method
   8     based on the platforma and available tools.
   9
  10     On Windows, it is recommended to have the Mark Hammond win32
  11     package installed. Alternatively, the Thomas Heller ctypes
  12     packages can also be used.
  13
  14     On Unix systems, the standard resource module provides the highest
  15     resolution timings. Unfortunately, it is not available on all Unix
  16     platforms.
  17
  18     If no supported timing methods based on process time can be found,
  19     the module reverts to the highest resolution wall-clock timer
  20     instead. The system time part will then always be 0.0.
  21
  22     The module exports one public API:
  23
  24     def systimes():
  25
  26         Return the current timer values for measuring user and system
  27         time as tuple of seconds (user_time, system_time).
  28
  29     Copyright (c) 2006, Marc-Andre Lemburg (mal@egenix.com). See the
  30     documentation for further information on copyrights, or contact
  31     the author. All Rights Reserved.
  32
  33 """
  34 import time, sys
  35
  36 #
  37 # Note: Please keep this module compatible to Python 1.5.2.
  38 #
  39 # TODOs:
  40 #
  41 # * Add ctypes wrapper for new clock_gettime() real-time POSIX APIs;
  42 #   these will then provide nano-second resolution where available.
  43 #
  44 # * Add a function that returns the resolution of systimes()
  45 #   values, ie. systimesres().
  46 #
  47
  48 ### Choose an implementation
  49
  50 SYSTIMES_IMPLEMENTATION = None
  51 USE_CTYPES_GETPROCESSTIMES = 'ctypes GetProcessTimes() wrapper'
  52 USE_WIN32PROCESS_GETPROCESSTIMES = 'win32process.GetProcessTimes()'
  53 USE_RESOURCE_GETRUSAGE = 'resource.getrusage()'
  54 USE_PROCESS_TIME_CLOCK = 'time.clock() (process time)'
  55 USE_WALL_TIME_CLOCK = 'time.clock() (wall-clock)'
  56 USE_WALL_TIME_TIME = 'time.time() (wall-clock)'
  57
  58 if sys.platform[:3] == 'win':
  59     # Windows platform
  60     try:
  61         import win32process
  62     except ImportError:
  63         try:
  64             import ctypes
  65         except ImportError:
  66             # Use the wall-clock implementation time.clock(), since this
  67             # is the highest resolution clock available on Windows
  68             SYSTIMES_IMPLEMENTATION = USE_WALL_TIME_CLOCK
  69         else:
  70             SYSTIMES_IMPLEMENTATION = USE_CTYPES_GETPROCESSTIMES
  71     else:
  72         SYSTIMES_IMPLEMENTATION = USE_WIN32PROCESS_GETPROCESSTIMES
  73 else:
  74     # All other platforms
  75     try:
  76         import resource
  77     except ImportError:
  78         pass
  79     else:
  80         SYSTIMES_IMPLEMENTATION = USE_RESOURCE_GETRUSAGE
  81
  82 # Fall-back solution
  83 if SYSTIMES_IMPLEMENTATION is None:
  84     # Check whether we can use time.clock() as approximation
  85     # for systimes()
  86     start = time.clock()
  87     time.sleep(0.1)
  88     stop = time.clock()
  89     if stop - start < 0.001:
  90         # Looks like time.clock() is usable (and measures process
  91         # time)
  92         SYSTIMES_IMPLEMENTATION = USE_PROCESS_TIME_CLOCK
  93     else:
  94         # Use wall-clock implementation time.time() since this provides
  95         # the highest resolution clock on most systems
  96         SYSTIMES_IMPLEMENTATION = USE_WALL_TIME_TIME
  97
  98 ### Implementations
  99
 100 def getrusage_systimes():
 101     return resource.getrusage(resource.RUSAGE_SELF)[:2]
 102
 103 def process_time_clock_systimes():
 104     return (time.clock(), 0.0)
 105
 106 def wall_clock_clock_systimes():
 107     return (time.clock(), 0.0)
 108
 109 def wall_clock_time_systimes():
 110     return (time.time(), 0.0)
 111
 112 # Number of clock ticks per second for the values returned
 113 # by GetProcessTimes() on Windows.
 114 #
 115 # Note: Ticks returned by GetProcessTimes() are 100ns intervals on
 116 # Windows XP. However, the process times are only updated with every
 117 # clock tick and the frequency of these is somewhat lower: depending
 118 # on the OS version between 10ms and 15ms. Even worse, the process
 119 # time seems to be allocated to process currently running when the
 120 # clock interrupt arrives, ie. it is possible that the current time
 121 # slice gets accounted to a different process.
 122
 123 WIN32_PROCESS_TIMES_TICKS_PER_SECOND = 1e7
 124
 125 def win32process_getprocesstimes_systimes():
 126     d = win32process.GetProcessTimes(win32process.GetCurrentProcess())
 127     return (d['UserTime'] / WIN32_PROCESS_TIMES_TICKS_PER_SECOND,
 128             d['KernelTime'] / WIN32_PROCESS_TIMES_TICKS_PER_SECOND)
 129
 130 def ctypes_getprocesstimes_systimes():
 131     creationtime = ctypes.c_ulonglong()
 132     exittime = ctypes.c_ulonglong()
 133     kerneltime = ctypes.c_ulonglong()
 134     usertime = ctypes.c_ulonglong()
 135     rc = ctypes.windll.kernel32.GetProcessTimes(
 136         ctypes.windll.kernel32.GetCurrentProcess(),
 137         ctypes.byref(creationtime),
 138         ctypes.byref(exittime),
 139         ctypes.byref(kerneltime),
 140         ctypes.byref(usertime))
 141     if not rc:
 142         raise TypeError('GetProcessTimes() returned an error')
 143     return (usertime.value / WIN32_PROCESS_TIMES_TICKS_PER_SECOND,
 144             kerneltime.value / WIN32_PROCESS_TIMES_TICKS_PER_SECOND)
 145
 146 # Select the default for the systimes() function
 147
 148 if SYSTIMES_IMPLEMENTATION is USE_RESOURCE_GETRUSAGE:
 149     systimes = getrusage_systimes
 150
 151 elif SYSTIMES_IMPLEMENTATION is USE_PROCESS_TIME_CLOCK:
 152     systimes = process_time_clock_systimes
 153
 154 elif SYSTIMES_IMPLEMENTATION is USE_WALL_TIME_CLOCK:
 155     systimes = wall_clock_clock_systimes
 156
 157 elif SYSTIMES_IMPLEMENTATION is USE_WALL_TIME_TIME:
 158     systimes = wall_clock_time_systimes
 159
 160 elif SYSTIMES_IMPLEMENTATION is USE_WIN32PROCESS_GETPROCESSTIMES:
 161     systimes = win32process_getprocesstimes_systimes
 162
 163 elif SYSTIMES_IMPLEMENTATION is USE_CTYPES_GETPROCESSTIMES:
 164     systimes = ctypes_getprocesstimes_systimes
 165
 166 else:
 167     raise TypeError('no suitable systimes() implementation found')
 168
 169 def processtime():
 170
 171     """ Return the total time spent on the process.
 172
 173         This is the sum of user and system time as returned by
 174         systimes().
 175
 176     """
 177     user, system = systimes()
 178     return user + system
 179
 180 ### Testing
 181
 182 def some_workload():
 183     x = 0L
 184     for i in xrange(10000000L):
 185         x = x + 1L
 186
 187 def test_workload():
 188     print 'Testing systimes() under load conditions'
 189     t0 = systimes()
 190     some_workload()
 191     t1 = systimes()
 192     print 'before:', t0
 193     print 'after:', t1
 194     print 'differences:', (t1[0] - t0[0], t1[1] - t0[1])
 195     print
 196
 197 def test_idle():
 198     print 'Testing systimes() under idle conditions'
 199     t0 = systimes()
 200     time.sleep(1)
 201     t1 = systimes()
 202     print 'before:', t0
 203     print 'after:', t1
 204     print 'differences:', (t1[0] - t0[0], t1[1] - t0[1])
 205     print
 206
 207 if __name__ == '__main__':
 208     print 'Using %s as timer' % SYSTIMES_IMPLEMENTATION
 209     print
 210     test_workload()
 211     test_idle()