text: # Copyright (c) 2012-2013 ARM Limited
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  # terms below provided that you ensure that this notice is replicated
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  # modified or unmodified, in source code or in binary form.
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  # Copyright (c) 2006-2008 The Regents of The University of Michigan
  # Copyright (c) 2010 Advanced Micro Devices, Inc.
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  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #
  # Authors: Lisa Hsu
  
  from __future__ import print_function
  
  import sys
  from os import getcwd
  from os.path import join as joinpath
  
  from common import CpuConfig
  from common import MemConfig
  
  import m5
  from m5.defines import buildEnv
  from m5.objects import *
  from m5.util import *
  
  addToPath('../common')
  
  def getCPUClass(cpu_type):
      """Returns the required cpu class and the mode of operation."""
      cls = CpuConfig.get(cpu_type)
      return cls, cls.memory_mode()
  
  def setCPUClass(options):
      """Returns two cpu classes and the initial mode of operation.
  
         Restoring from a checkpoint or fast forwarding through a benchmark
         can be done using one type of cpu, and then the actual
         simulation can be carried out using another type. This function
         returns these two types of cpus and the initial mode of operation
         depending on the options provided.
      """
  
      TmpClass, test_mem_mode = getCPUClass(options.cpu_type)
      CPUClass = None
      if TmpClass.require_caches() and \
              not options.caches and not options.ruby:
          fatal("%s must be used with caches" % options.cpu_type)
  
      if options.checkpoint_restore != None:
          if options.restore_with_cpu != options.cpu_type:
              CPUClass = TmpClass
              TmpClass, test_mem_mode = getCPUClass(options.restore_with_cpu)
      elif options.fast_forward:
          CPUClass = TmpClass
          TmpClass = AtomicSimpleCPU
          test_mem_mode = 'atomic'
  
      # Ruby only supports atomic accesses in noncaching mode
      if test_mem_mode == 'atomic' and options.ruby:
          warn("Memory mode will be changed to atomic_noncaching")
          test_mem_mode = 'atomic_noncaching'
  
      return (TmpClass, test_mem_mode, CPUClass)
  
  def setMemClass(options):
      """Returns a memory controller class."""
  
      return MemConfig.get(options.mem_type)
  
  def setWorkCountOptions(system, options):
      if options.work_item_id != None:
          system.work_item_id = options.work_item_id
      if options.num_work_ids != None:
          system.num_work_ids = options.num_work_ids
      if options.work_begin_cpu_id_exit != None:
          system.work_begin_cpu_id_exit = options.work_begin_cpu_id_exit
      if options.work_end_exit_count != None:
          system.work_end_exit_count = options.work_end_exit_count
      if options.work_end_checkpoint_count != None:
          system.work_end_ckpt_count = options.work_end_checkpoint_count
      if options.work_begin_exit_count != None:
          system.work_begin_exit_count = options.work_begin_exit_count
      if options.work_begin_checkpoint_count != None:
          system.work_begin_ckpt_count = options.work_begin_checkpoint_count
      if options.work_cpus_checkpoint_count != None:
          system.work_cpus_ckpt_count = options.work_cpus_checkpoint_count
  
  def findCptDir(options, cptdir, testsys):
      """Figures out the directory from which the checkpointed state is read.
  
      There are two different ways in which the directories holding checkpoints
      can be named --
      1. cpt.<benchmark name>.<instruction count when the checkpoint was taken>
      2. cpt.<some number, usually the tick value when the checkpoint was taken>
  
      This function parses through the options to figure out which one of the
      above should be used for selecting the checkpoint, and then figures out
      the appropriate directory.
      """
  
      from os.path import isdir, exists
      from os import listdir
      import re
  
      if not isdir(cptdir):
          fatal("checkpoint dir %s does not exist!", cptdir)
  
      cpt_starttick = 0
      if options.at_instruction or options.simpoint:
          inst = options.checkpoint_restore
          if options.simpoint:
              # assume workload 0 has the simpoint
              if testsys.cpu[0].workload[0].simpoint == 0:
                  fatal('Unable to find simpoint')
              inst += int(testsys.cpu[0].workload[0].simpoint)
  
          checkpoint_dir = joinpath(cptdir, "cpt.%s.%s" % (options.bench, inst))
          if not exists(checkpoint_dir):
              fatal("Unable to find checkpoint directory %s", checkpoint_dir)
  
      elif options.restore_simpoint_checkpoint:
          # Restore from SimPoint checkpoints
          # Assumes that the checkpoint dir names are formatted as follows:
          dirs = listdir(cptdir)
          expr = re.compile('cpt\.simpoint_(\d+)_inst_(\d+)' +
                      '_weight_([\d\.e\-]+)_interval_(\d+)_warmup_(\d+)')
          cpts = []
          for dir in dirs:
              match = expr.match(dir)
              if match:
                  cpts.append(dir)
          cpts.sort()
  
          cpt_num = options.checkpoint_restore
          if cpt_num > len(cpts):
              fatal('Checkpoint %d not found', cpt_num)
          checkpoint_dir = joinpath(cptdir, cpts[cpt_num - 1])
          match = expr.match(cpts[cpt_num - 1])
          if match:
              index = int(match.group(1))
              start_inst = int(match.group(2))
              weight_inst = float(match.group(3))
              interval_length = int(match.group(4))
              warmup_length = int(match.group(5))
          print("Resuming from", checkpoint_dir)
          simpoint_start_insts = []
          simpoint_start_insts.append(warmup_length)
          simpoint_start_insts.append(warmup_length + interval_length)
          testsys.cpu[0].simpoint_start_insts = simpoint_start_insts
          if testsys.switch_cpus != None:
              testsys.switch_cpus[0].simpoint_start_insts = simpoint_start_insts
  
          print("Resuming from SimPoint", end=' ')
          print("#%d, start_inst:%d, weight:%f, interval:%d, warmup:%d" %
              (index, start_inst, weight_inst, interval_length, warmup_length))
  
      else:
          dirs = listdir(cptdir)
          expr = re.compile('cpt\.([0-9]+)')
          cpts = []
          for dir in dirs:
              match = expr.match(dir)
              if match:
                  cpts.append(match.group(1))
  
          cpts.sort(lambda a,b: cmp(long(a), long(b)))
  
          cpt_num = options.checkpoint_restore
          if cpt_num > len(cpts):
              fatal('Checkpoint %d not found', cpt_num)
  
          cpt_starttick = int(cpts[cpt_num - 1])
          checkpoint_dir = joinpath(cptdir, "cpt.%s" % cpts[cpt_num - 1])
  
      return cpt_starttick, checkpoint_dir
  
  def scriptCheckpoints(options, maxtick, cptdir):
      if options.at_instruction or options.simpoint:
          checkpoint_inst = int(options.take_checkpoints)
  
          # maintain correct offset if we restored from some instruction
          if options.checkpoint_restore != None:
              checkpoint_inst += options.checkpoint_restore
  
          print("Creating checkpoint at inst:%d" % (checkpoint_inst))
          print("under simulating!!!!")
          exit_event = m5.simulate()
          exit_cause = exit_event.getCause()
          print("exit cause = %s" % exit_cause)
  
          # skip checkpoint instructions should they exist
          while exit_cause == "checkpoint":
              exit_event = m5.simulate()
              exit_cause = exit_event.getCause()
  
          if exit_cause == "a thread reached the max instruction count":
              m5.checkpoint(joinpath(cptdir, "cpt.%s.%d" % \
                      (options.bench, checkpoint_inst)))
              print("Checkpoint written.")
  
      else:
          when, period = options.take_checkpoints.split(",", 1)
          when = int(when)
          period = int(period)
          num_checkpoints = 0
  
          exit_event = m5.simulate(when - m5.curTick())
          exit_cause = exit_event.getCause()
          while exit_cause == "checkpoint":
              exit_event = m5.simulate(when - m5.curTick())
              exit_cause = exit_event.getCause()
  
          if exit_cause == "simulate() limit reached":
              m5.checkpoint(joinpath(cptdir, "cpt.%d"))
              num_checkpoints += 1
  
          sim_ticks = when
          max_checkpoints = options.max_checkpoints
  
          while num_checkpoints < max_checkpoints and \
                  exit_cause == "simulate() limit reached":
              if (sim_ticks + period) > maxtick:
                  exit_event = m5.simulate(maxtick - sim_ticks)
                  exit_cause = exit_event.getCause()
                  break
              else:
                  exit_event = m5.simulate(period)
                  exit_cause = exit_event.getCause()
                  sim_ticks += period
                  while exit_event.getCause() == "checkpoint":
                      exit_event = m5.simulate(sim_ticks - m5.curTick())
                  if exit_event.getCause() == "simulate() limit reached":
                      m5.checkpoint(joinpath(cptdir, "cpt.%d"))
                      num_checkpoints += 1
  
      return exit_event
  
  def benchCheckpoints(options, maxtick, cptdir):
      exit_event = m5.simulate(maxtick - m5.curTick())
      exit_cause = exit_event.getCause()
  
      num_checkpoints = 0
      max_checkpoints = options.max_checkpoints
  
      while exit_cause == "checkpoint":
          m5.checkpoint(joinpath(cptdir, "cpt.%d"))
          num_checkpoints += 1
          if num_checkpoints == max_checkpoints:
              exit_cause = "maximum %d checkpoints dropped" % max_checkpoints
              break
  
          exit_event = m5.simulate(maxtick - m5.curTick())
          exit_cause = exit_event.getCause()
  
      return exit_event
  
  # Set up environment for taking SimPoint checkpoints
  # Expecting SimPoint files generated by SimPoint 3.2
  def parseSimpointAnalysisFile(options, testsys):
      import re
  
      simpoint_filename, weight_filename, interval_length, warmup_length = \
          options.take_simpoint_checkpoints.split(",", 3)
      print("simpoint analysis file:", simpoint_filename)
      print("simpoint weight file:", weight_filename)
      print("interval length:", interval_length)
      print("warmup length:", warmup_length)
  
      interval_length = int(interval_length)
      warmup_length = int(warmup_length)
  
      # Simpoint analysis output starts interval counts with 0.
      simpoints = []
      simpoint_start_insts = []
  
      # Read in SimPoint analysis files
      simpoint_file = open(simpoint_filename)
      weight_file = open(weight_filename)
      while True:
          line = simpoint_file.readline()
          if not line:
              break
          m = re.match("(\d+)\s+(\d+)", line)
          if m:
              interval = int(m.group(1))
          else:
              fatal('unrecognized line in simpoint file!')
  
          line = weight_file.readline()
          if not line:
              fatal('not enough lines in simpoint weight file!')
          m = re.match("([0-9\.e\-]+)\s+(\d+)", line)
          if m:
              weight = float(m.group(1))
          else:
              fatal('unrecognized line in simpoint weight file!')
  
          if (interval * interval_length - warmup_length > 0):
              starting_inst_count = \
                  interval * interval_length - warmup_length
              actual_warmup_length = warmup_length
          else:
              # Not enough room for proper warmup
              # Just starting from the beginning
              starting_inst_count = 0
              actual_warmup_length = interval * interval_length
  
          simpoints.append((interval, weight, starting_inst_count,
              actual_warmup_length))
  
      # Sort SimPoints by starting inst count
      simpoints.sort(key=lambda obj: obj[2])
      for s in simpoints:
          interval, weight, starting_inst_count, actual_warmup_length = s
          print(str(interval), str(weight), starting_inst_count,
              actual_warmup_length)
          simpoint_start_insts.append(starting_inst_count)
  
      print("Total # of simpoints:", len(simpoints))
      testsys.cpu[0].simpoint_start_insts = simpoint_start_insts
  
      return (simpoints, interval_length)
  
  def takeSimpointCheckpoints(simpoints, interval_length, cptdir):
      num_checkpoints = 0
      index = 0
      last_chkpnt_inst_count = -1
      for simpoint in simpoints:
          interval, weight, starting_inst_count, actual_warmup_length = simpoint
          if starting_inst_count == last_chkpnt_inst_count:
              # checkpoint starting point same as last time
              # (when warmup period longer than starting point)
              exit_cause = "simpoint starting point found"
              code = 0
          else:
              exit_event = m5.simulate()
  
              # skip checkpoint instructions should they exist
              while exit_event.getCause() == "checkpoint":
                  print("Found 'checkpoint' exit event...ignoring...")
                  exit_event = m5.simulate()
  
              exit_cause = exit_event.getCause()
              code = exit_event.getCode()
  
          if exit_cause == "simpoint starting point found":
              m5.checkpoint(joinpath(cptdir,
                  "cpt.simpoint_%02d_inst_%d_weight_%f_interval_%d_warmup_%d"
                  % (index, starting_inst_count, weight, interval_length,
                  actual_warmup_length)))
              print("Checkpoint #%d written. start inst:%d weight:%f" %
                  (num_checkpoints, starting_inst_count, weight))
              num_checkpoints += 1
              last_chkpnt_inst_count = starting_inst_count
          else:
              break
          index += 1
  
      print('Exiting @ tick %i because %s' % (m5.curTick(), exit_cause))
      print("%d checkpoints taken" % num_checkpoints)
      sys.exit(code)
  
  def restoreSimpointCheckpoint():
      exit_event = m5.simulate()
      exit_cause = exit_event.getCause()
  
      if exit_cause == "simpoint starting point found":
          print("Warmed up! Dumping and resetting stats!")
          m5.stats.dump()
          m5.stats.reset()
  
          exit_event = m5.simulate()
          exit_cause = exit_event.getCause()
  
          if exit_cause == "simpoint starting point found":
              print("Done running SimPoint!")
              sys.exit(exit_event.getCode())
  
      print('Exiting @ tick %i because %s' % (m5.curTick(), exit_cause))
      sys.exit(exit_event.getCode())
  
  def repeatSwitch(testsys, repeat_switch_cpu_list, maxtick, switch_freq):
      print("starting switch loop")
      while True:
          exit_event = m5.simulate(switch_freq)
          exit_cause = exit_event.getCause()
  
          if exit_cause != "simulate() limit reached":
              return exit_event
  
          m5.switchCpus(testsys, repeat_switch_cpu_list)
  
          tmp_cpu_list = []
          for old_cpu, new_cpu in repeat_switch_cpu_list:
              tmp_cpu_list.append((new_cpu, old_cpu))
          repeat_switch_cpu_list = tmp_cpu_list
  
          if (maxtick - m5.curTick()) <= switch_freq:
              exit_event = m5.simulate(maxtick - m5.curTick())
              return exit_event
  
  def run(options, root, testsys, cpu_class):
      if options.checkpoint_dir:
          cptdir = options.checkpoint_dir
      elif m5.options.outdir:
          cptdir = m5.options.outdir
      else:
          cptdir = getcwd()
  
      if options.fast_forward and options.checkpoint_restore != None:
          fatal("Can't specify both --fast-forward and --checkpoint-restore")
  
      if options.standard_switch and not options.caches:
          fatal("Must specify --caches when using --standard-switch")
  
      if options.standard_switch and options.repeat_switch:
          fatal("Can't specify both --standard-switch and --repeat-switch")
  
      if options.repeat_switch and options.take_checkpoints:
          fatal("Can't specify both --repeat-switch and --take-checkpoints")
  
      np = options.num_cpus
      switch_cpus = None
  
      if options.prog_interval:
          for i in xrange(np):
              testsys.cpu[i].progress_interval = options.prog_interval
  
      if options.maxinsts:
          for i in xrange(np):
              testsys.cpu[i].max_insts_any_thread = options.maxinsts
  
      if cpu_class:
          switch_cpus = [cpu_class(switched_out=True, cpu_id=(i))
                         for i in xrange(np)]
  
          for i in xrange(np):
              if options.fast_forward:
                  testsys.cpu[i].max_insts_any_thread = int(options.fast_forward)
              switch_cpus[i].system = testsys
              switch_cpus[i].workload = testsys.cpu[i].workload
              switch_cpus[i].clk_domain = testsys.cpu[i].clk_domain
              switch_cpus[i].progress_interval = \
                  testsys.cpu[i].progress_interval
              switch_cpus[i].isa = testsys.cpu[i].isa
              # simulation period
              if options.maxinsts:
                  switch_cpus[i].max_insts_any_thread = options.maxinsts
              # Add checker cpu if selected
              if options.checker:
                  switch_cpus[i].addCheckerCpu()
  
          # If elastic tracing is enabled attach the elastic trace probe
          # to the switch CPUs
          if options.elastic_trace_en:
              CpuConfig.config_etrace(cpu_class, switch_cpus, options)
  
          testsys.switch_cpus = switch_cpus
          switch_cpu_list = [(testsys.cpu[i], switch_cpus[i]) for i in xrange(np)]
  
      if options.repeat_switch:
          switch_class = getCPUClass(options.cpu_type)[0]
          if switch_class.require_caches() and \
                  not options.caches:
              print("%s: Must be used with caches" % str(switch_class))
              sys.exit(1)
          if not switch_class.support_take_over():
              print("%s: CPU switching not supported" % str(switch_class))
              sys.exit(1)
  
          repeat_switch_cpus = [switch_class(switched_out=True, \
                                                 cpu_id=(i)) for i in xrange(np)]
  
          for i in xrange(np):
              repeat_switch_cpus[i].system = testsys
              repeat_switch_cpus[i].workload = testsys.cpu[i].workload
              repeat_switch_cpus[i].clk_domain = testsys.cpu[i].clk_domain
              repeat_switch_cpus[i].isa = testsys.cpu[i].isa
  
              if options.maxinsts:
                  repeat_switch_cpus[i].max_insts_any_thread = options.maxinsts
  
              if options.checker:
                  repeat_switch_cpus[i].addCheckerCpu()
  
          testsys.repeat_switch_cpus = repeat_switch_cpus
  
          if cpu_class:
              repeat_switch_cpu_list = [(switch_cpus[i], repeat_switch_cpus[i])
                                        for i in xrange(np)]
          else:
              repeat_switch_cpu_list = [(testsys.cpu[i], repeat_switch_cpus[i])
                                        for i in xrange(np)]
  
      if options.standard_switch:
          switch_cpus = [TimingSimpleCPU(switched_out=True, cpu_id=(i))
                         for i in xrange(np)]
          switch_cpus_1 = [DerivO3CPU(switched_out=True, cpu_id=(i))
                          for i in xrange(np)]
  
          for i in xrange(np):
              switch_cpus[i].system =  testsys
              switch_cpus_1[i].system =  testsys
              switch_cpus[i].workload = testsys.cpu[i].workload
              switch_cpus_1[i].workload = testsys.cpu[i].workload
              switch_cpus[i].clk_domain = testsys.cpu[i].clk_domain
              switch_cpus_1[i].clk_domain = testsys.cpu[i].clk_domain
              switch_cpus[i].isa = testsys.cpu[i].isa
              switch_cpus_1[i].isa = testsys.cpu[i].isa
  
              # if restoring, make atomic cpu simulate only a few instructions
              if options.checkpoint_restore != None:
                  testsys.cpu[i].max_insts_any_thread = 1
              # Fast forward to specified location if we are not restoring
              elif options.fast_forward:
                  testsys.cpu[i].max_insts_any_thread = int(options.fast_forward)
              # Fast forward to a simpoint (warning: time consuming)
              elif options.simpoint:
                  if testsys.cpu[i].workload[0].simpoint == 0:
                      fatal('simpoint not found')
                  testsys.cpu[i].max_insts_any_thread = \
                      testsys.cpu[i].workload[0].simpoint
              # No distance specified, just switch
              else:
                  testsys.cpu[i].max_insts_any_thread = 1
  
              # warmup period
              if options.warmup_insts:
                  switch_cpus[i].max_insts_any_thread =  options.warmup_insts
  
              # simulation period
              if options.maxinsts:
                  switch_cpus_1[i].max_insts_any_thread = options.maxinsts
  
              # attach the checker cpu if selected
              if options.checker:
                  switch_cpus[i].addCheckerCpu()
                  switch_cpus_1[i].addCheckerCpu()
  
          testsys.switch_cpus = switch_cpus
          testsys.switch_cpus_1 = switch_cpus_1
          switch_cpu_list = [(testsys.cpu[i], switch_cpus[i]) for i in xrange(np)]
          switch_cpu_list1 = [(switch_cpus[i], switch_cpus_1[i]) for i in xrange(np)]
  
      # set the checkpoint in the cpu before m5.instantiate is called
      if options.take_checkpoints != None and \
             (options.simpoint or options.at_instruction):
          offset = int(options.take_checkpoints)
          # Set an instruction break point
          if options.simpoint:
              for i in xrange(np):
                  if testsys.cpu[i].workload[0].simpoint == 0:
                      fatal('no simpoint for testsys.cpu[%d].workload[0]', i)
                  checkpoint_inst = int(testsys.cpu[i].workload[0].simpoint) + offset
                  testsys.cpu[i].max_insts_any_thread = checkpoint_inst
                  # used for output below
                  options.take_checkpoints = checkpoint_inst
          else:
              options.take_checkpoints = offset
              # Set all test cpus with the right number of instructions
              # for the upcoming simulation
              for i in xrange(np):
                  testsys.cpu[i].max_insts_any_thread = offset
  
      if options.take_simpoint_checkpoints != None:
          simpoints, interval_length = parseSimpointAnalysisFile(options, testsys)
  
      checkpoint_dir = None
      if options.checkpoint_restore:
          cpt_starttick, checkpoint_dir = findCptDir(options, cptdir, testsys)
      m5.instantiate(checkpoint_dir)
  
      # Initialization is complete.  If we're not in control of simulation
      # (that is, if we're a slave simulator acting as a component in another
      #  'master' simulator) then we're done here.  The other simulator will
      # call simulate() directly. --initialize-only is used to indicate this.
      if options.initialize_only:
          return
  
      # Handle the max tick settings now that tick frequency was resolved
      # during system instantiation
      # NOTE: the maxtick variable here is in absolute ticks, so it must
      # include any simulated ticks before a checkpoint
      explicit_maxticks = 0
      maxtick_from_abs = m5.MaxTick
      maxtick_from_rel = m5.MaxTick
      maxtick_from_maxtime = m5.MaxTick
      if options.abs_max_tick:
          maxtick_from_abs = options.abs_max_tick
          explicit_maxticks += 1
      if options.rel_max_tick:
          maxtick_from_rel = options.rel_max_tick
          if options.checkpoint_restore:
              # NOTE: this may need to be updated if checkpoints ever store
              # the ticks per simulated second
              maxtick_from_rel += cpt_starttick
              if options.at_instruction or options.simpoint:
                  warn("Relative max tick specified with --at-instruction or" \
                       " --simpoint\n      These options don't specify the " \
                       "checkpoint start tick, so assuming\n      you mean " \
                       "absolute max tick")
          explicit_maxticks += 1
      if options.maxtime:
          maxtick_from_maxtime = m5.ticks.fromSeconds(options.maxtime)
          explicit_maxticks += 1
      if explicit_maxticks > 1:
          warn("Specified multiple of --abs-max-tick, --rel-max-tick, --maxtime."\
               " Using least")
      maxtick = min([maxtick_from_abs, maxtick_from_rel, maxtick_from_maxtime])
  
      if options.checkpoint_restore != None and maxtick < cpt_starttick:
          fatal("Bad maxtick (%d) specified: " \
                "Checkpoint starts starts from tick: %d", maxtick, cpt_starttick)
  
      if options.standard_switch or cpu_class:
          if options.standard_switch:
              print("Switch at instruction count:%s" %
                      str(testsys.cpu[0].max_insts_any_thread))
              exit_event = m5.simulate()
          elif cpu_class and options.fast_forward:
              print("Switch at instruction count:%s" %
                      str(testsys.cpu[0].max_insts_any_thread))
              exit_event = m5.simulate()
          else:
              print("Switch at curTick count:%s" % str(10000))
              exit_event = m5.simulate(10000)
          print("Switched CPUS @ tick %s" % (m5.curTick()))
  
          m5.switchCpus(testsys, switch_cpu_list)
  
          if options.standard_switch:
              print("Switch at instruction count:%d" %
                      (testsys.switch_cpus[0].max_insts_any_thread))
  
              #warmup instruction count may have already been set
              if options.warmup_insts:
                  exit_event = m5.simulate()
              else:
                  exit_event = m5.simulate(options.standard_switch)
              print("Switching CPUS @ tick %s" % (m5.curTick()))
              print("Simulation ends instruction count:%d" %
                      (testsys.switch_cpus_1[0].max_insts_any_thread))
              m5.switchCpus(testsys, switch_cpu_list1)
  
      # If we're taking and restoring checkpoints, use checkpoint_dir
      # option only for finding the checkpoints to restore from.  This
      # lets us test checkpointing by restoring from one set of
      # checkpoints, generating a second set, and then comparing them.
      if (options.take_checkpoints or options.take_simpoint_checkpoints) \
          and options.checkpoint_restore:
  
          if m5.options.outdir:
              cptdir = m5.options.outdir
          else:
              cptdir = getcwd()
  
      if options.take_checkpoints != None :
          # Checkpoints being taken via the command line at <when> and at
          # subsequent periods of <period>.  Checkpoint instructions
          # received from the benchmark running are ignored and skipped in
          # favor of command line checkpoint instructions.
          exit_event = scriptCheckpoints(options, maxtick, cptdir)
  
      # Take SimPoint checkpoints
      elif options.take_simpoint_checkpoints != None:
          takeSimpointCheckpoints(simpoints, interval_length, cptdir)
  
      # Restore from SimPoint checkpoints
      elif options.restore_simpoint_checkpoint != None:
          restoreSimpointCheckpoint()
  
      else:
          if options.fast_forward:
              m5.stats.reset()
          print("**** REAL SIMULATION ****")
  
          # If checkpoints are being taken, then the checkpoint instruction
          # will occur in the benchmark code it self.
          if options.repeat_switch and maxtick > options.repeat_switch:
              exit_event = repeatSwitch(testsys, repeat_switch_cpu_list,
                                        maxtick, options.repeat_switch)
          else:
              exit_event = benchCheckpoints(options, maxtick, cptdir)
  
      print('Exiting @ tick %i because %s' %
            (m5.curTick(), exit_event.getCause()))
      if options.checkpoint_at_end:
          m5.checkpoint(joinpath(cptdir, "cpt.%d"))
  
      if not m5.options.interactive:
          sys.exit(exit_event.getCode())
  