src/python/m5/ticks.py

   1 # Copyright (c) 2007 The Regents of The University of Michigan
   2 # All rights reserved.
   3 #
   4 # Redistribution and use in source and binary forms, with or without
   5 # modification, are permitted provided that the following conditions are
   6 # met: redistributions of source code must retain the above copyright
   7 # notice, this list of conditions and the following disclaimer;
   8 # redistributions in binary form must reproduce the above copyright
   9 # notice, this list of conditions and the following disclaimer in the
  10 # documentation and/or other materials provided with the distribution;
  11 # neither the name of the copyright holders nor the names of its
  12 # contributors may be used to endorse or promote products derived from
  13 # this software without specific prior written permission.
  14 #
  15 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  17 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  18 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  19 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  20 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  21 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26 #
  27 # Authors: Nathan Binkert
  28
  29 import sys
  30 from m5.util import warn
  31
  32 tps = 1.0e12         # default to 1 THz (1 Tick == 1 ps)
  33 tps_fixed = False    # once set to true, can't be changed
  34
  35 # fix the global frequency and tell C++ about it
  36 def fixGlobalFrequency():
  37     import _m5.core
  38     global tps, tps_fixed
  39     if not tps_fixed:
  40         tps_fixed = True
  41         _m5.core.setClockFrequency(int(tps))
  42         print "Global frequency set at %d ticks per second" % int(tps)
  43
  44 def setGlobalFrequency(ticksPerSecond):
  45     from m5.util import convert
  46
  47     global tps, tps_fixed
  48
  49     if tps_fixed:
  50         raise AttributeError, \
  51               "Global frequency already fixed at %f ticks/s." % tps
  52
  53     if isinstance(ticksPerSecond, (int, long)):
  54         tps = ticksPerSecond
  55     elif isinstance(ticksPerSecond, float):
  56         tps = ticksPerSecond
  57     elif isinstance(ticksPerSecond, str):
  58         tps = round(convert.anyToFrequency(ticksPerSecond))
  59     else:
  60         raise TypeError, \
  61               "wrong type '%s' for ticksPerSecond" % type(ticksPerSecond)
  62
  63 # how big does a rounding error need to be before we warn about it?
  64 frequency_tolerance = 0.001  # 0.1%
  65
  66 def fromSeconds(value):
  67     if not isinstance(value, float):
  68         raise TypeError, "can't convert '%s' to type tick" % type(value)
  69
  70     # once someone needs to convert to seconds, the global frequency
  71     # had better be fixed
  72     if not tps_fixed:
  73         raise AttributeError, \
  74               "In order to do conversions, the global frequency must be fixed"
  75
  76     if value == 0:
  77         return 0
  78
  79     # convert the value from time to ticks
  80     value *= tps
  81
  82     int_value = int(round(value))
  83     err = (value - int_value) / value
  84     if err > frequency_tolerance:
  85         warn("rounding error > tolerance\n    %f rounded to %d", value,
  86             int_value)
  87     return int_value
  88
  89 __all__ = [ 'setGlobalFrequency', 'fixGlobalFrequency', 'fromSeconds',
  90             'frequency_tolerance' ]