configs/example/memtest.py

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  38 #
  39 # Authors: Ron Dreslinski
  40 #          Andreas Hansson
  41
  42 import optparse
  43 import random
  44 import sys
  45
  46 import m5
  47 from m5.objects import *
  48
  49 # This example script stress tests the memory system by creating false
  50 # sharing in a tree topology. At the bottom of the tree is a shared
  51 # memory, and then at each level a number of testers are attached,
  52 # along with a number of caches that them selves fan out to subtrees
  53 # of testers and caches. Thus, it is possible to create a system with
  54 # arbitrarily deep cache hierarchies, sharing or no sharing of caches,
  55 # and testers not only at the L1s, but also at the L2s, L3s etc.
  56
  57 parser = optparse.OptionParser()
  58
  59 parser.add_option("-a", "--atomic", action="store_true",
  60                   help="Use atomic (non-timing) mode")
  61 parser.add_option("-b", "--blocking", action="store_true",
  62                   help="Use blocking caches")
  63 parser.add_option("-l", "--maxloads", metavar="N", default=0,
  64                   help="Stop after N loads")
  65 parser.add_option("-m", "--maxtick", type="int", default=m5.MaxTick,
  66                   metavar="T",
  67                   help="Stop after T ticks")
  68
  69 # The tree specification consists of two colon-separated lists of one
  70 # or more integers, one for the caches, and one for the testers. The
  71 # first integer is the number of caches/testers closest to main
  72 # memory. Each cache then fans out to a subtree. The last integer in
  73 # the list is the number of caches/testers associated with the
  74 # uppermost level of memory. The other integers (if any) specify the
  75 # number of caches/testers connected at each level of the crossbar
  76 # hierarchy. The tester string should have one element more than the
  77 # cache string as there should always be testers attached to the
  78 # uppermost caches.
  79
  80 parser.add_option("-c", "--caches", type="string", default="2:2:1",
  81                   help="Colon-separated cache hierarchy specification, "
  82                   "see script comments for details "
  83                   "[default: %default]")
  84 parser.add_option("-t", "--testers", type="string", default="1:1:0:2",
  85                   help="Colon-separated tester hierarchy specification, "
  86                   "see script comments for details "
  87                   "[default: %default]")
  88 parser.add_option("-f", "--functional", type="int", default=0,
  89                   metavar="PCT",
  90                   help="Target percentage of functional accesses "
  91                   "[default: %default]")
  92 parser.add_option("-u", "--uncacheable", type="int", default=0,
  93                   metavar="PCT",
  94                   help="Target percentage of uncacheable accesses "
  95                   "[default: %default]")
  96 parser.add_option("-r", "--random", action="store_true",
  97                   help="Generate a random tree topology")
  98 parser.add_option("--progress", type="int", default=100000,
  99                   metavar="NLOADS",
 100                   help="Progress message interval "
 101                   "[default: %default]")
 102 parser.add_option("--sys-clock", action="store", type="string",
 103                   default='1GHz',
 104                   help = """Top-level clock for blocks running at system
 105                   speed""")
 106
 107 (options, args) = parser.parse_args()
 108
 109 if args:
 110      print "Error: script doesn't take any positional arguments"
 111      sys.exit(1)
 112
 113 # Get the total number of testers
 114 def numtesters(cachespec, testerspec):
 115      # Determine the tester multiplier for each level as the
 116      # elements are per subsystem and it fans out
 117      multiplier = [1]
 118      for c in cachespec:
 119           multiplier.append(multiplier[-1] * c)
 120
 121      total = 0
 122      for t, m in zip(testerspec, multiplier):
 123           total += t * m
 124
 125      return total
 126
 127 block_size = 64
 128
 129 # Start by parsing the command line options and do some basic sanity
 130 # checking
 131 if options.random:
 132      # Generate a tree with a valid number of testers
 133      while True:
 134           tree_depth = random.randint(1, 4)
 135           cachespec = [random.randint(1, 3) for i in range(tree_depth)]
 136           testerspec = [random.randint(1, 3) for i in range(tree_depth + 1)]
 137           if numtesters(cachespec, testerspec) < block_size:
 138                break
 139
 140      print "Generated random tree -c", ':'.join(map(str, cachespec)), \
 141          "-t", ':'.join(map(str, testerspec))
 142 else:
 143      try:
 144           cachespec = [int(x) for x in options.caches.split(':')]
 145           testerspec = [int(x) for x in options.testers.split(':')]
 146      except:
 147           print "Error: Unable to parse caches or testers option"
 148           sys.exit(1)
 149
 150      if len(cachespec) < 1:
 151           print "Error: Must have at least one level of caches"
 152           sys.exit(1)
 153
 154      if len(cachespec) != len(testerspec) - 1:
 155           print "Error: Testers must have one element more than caches"
 156           sys.exit(1)
 157
 158      if testerspec[-1] == 0:
 159           print "Error: Must have testers at the uppermost level"
 160           sys.exit(1)
 161
 162      for t in testerspec:
 163           if t < 0:
 164                print "Error: Cannot have a negative number of testers"
 165                sys.exit(1)
 166
 167      for c in cachespec:
 168           if c < 1:
 169                print "Error: Must have 1 or more caches at each level"
 170                sys.exit(1)
 171
 172      if numtesters(cachespec, testerspec) > block_size:
 173           print "Error: Limited to %s testers because of false sharing" \
 174               % (block_size)
 175           sys.exit(1)
 176
 177 # Define a prototype L1 cache that we scale for all successive levels
 178 proto_l1 = Cache(size = '32kB', assoc = 4,
 179                  hit_latency = 1, response_latency = 1,
 180                  tgts_per_mshr = 8)
 181
 182 if options.blocking:
 183      proto_l1.mshrs = 1
 184 else:
 185      proto_l1.mshrs = 4
 186
 187 cache_proto = [proto_l1]
 188
 189 # Now add additional cache levels (if any) by scaling L1 params, the
 190 # first element is Ln, and the last element L1
 191 for scale in cachespec[:-1]:
 192      # Clone previous level and update params
 193      prev = cache_proto[0]
 194      next = prev()
 195      next.size = prev.size * scale
 196      next.hit_latency = prev.hit_latency * 10
 197      next.response_latency = prev.response_latency * 10
 198      next.assoc = prev.assoc * scale
 199      next.mshrs = prev.mshrs * scale
 200      cache_proto.insert(0, next)
 201
 202 # Make a prototype for the tester to be used throughout
 203 proto_tester = MemTest(max_loads = options.maxloads,
 204                        percent_functional = options.functional,
 205                        percent_uncacheable = options.uncacheable,
 206                        progress_interval = options.progress)
 207
 208 # Set up the system along with a simple memory and reference memory
 209 system = System(physmem = SimpleMemory(),
 210                 cache_line_size = block_size)
 211
 212 system.voltage_domain = VoltageDomain(voltage = '1V')
 213
 214 system.clk_domain = SrcClockDomain(clock =  options.sys_clock,
 215                         voltage_domain = system.voltage_domain)
 216
 217 # For each level, track the next subsys index to use
 218 next_subsys_index = [0] * (len(cachespec) + 1)
 219
 220 # Recursive function to create a sub-tree of the cache and tester
 221 # hierarchy
 222 def make_cache_level(ncaches, prototypes, level, next_cache):
 223      global next_subsys_index, proto_l1, testerspec, proto_tester
 224
 225      index = next_subsys_index[level]
 226      next_subsys_index[level] += 1
 227
 228      # Create a subsystem to contain the crossbar and caches, and
 229      # any testers
 230      subsys = SubSystem()
 231      setattr(system, 'l%dsubsys%d' % (level, index), subsys)
 232
 233      # The levels are indexing backwards through the list
 234      ntesters = testerspec[len(cachespec) - level]
 235
 236      # Scale the progress threshold as testers higher up in the tree
 237      # (smaller level) get a smaller portion of the overall bandwidth,
 238      # and also make the interval of packet injection longer for the
 239      # testers closer to the memory (larger level) to prevent them
 240      # hogging all the bandwidth
 241      limit = (len(cachespec) - level + 1) * 100000000
 242      testers = [proto_tester(interval = 10 * (level * level + 1),
 243                              progress_check = limit) \
 244                      for i in xrange(ntesters)]
 245      if ntesters:
 246           subsys.tester = testers
 247
 248      if level != 0:
 249           # Create a crossbar and add it to the subsystem, note that
 250           # we do this even with a single element on this level
 251           xbar = L2XBar()
 252           subsys.xbar = xbar
 253           if next_cache:
 254                xbar.master = next_cache.cpu_side
 255
 256           # Create and connect the caches, both the ones fanning out
 257           # to create the tree, and the ones used to connect testers
 258           # on this level
 259           tree_caches = [prototypes[0]() for i in xrange(ncaches[0])]
 260           tester_caches = [proto_l1() for i in xrange(ntesters)]
 261
 262           subsys.cache = tester_caches + tree_caches
 263           for cache in tree_caches:
 264                cache.mem_side = xbar.slave
 265                make_cache_level(ncaches[1:], prototypes[1:], level - 1, cache)
 266           for tester, cache in zip(testers, tester_caches):
 267                tester.port = cache.cpu_side
 268                cache.mem_side = xbar.slave
 269      else:
 270           if not next_cache:
 271                print "Error: No next-level cache at top level"
 272                sys.exit(1)
 273
 274           if ntesters > 1:
 275                # Create a crossbar and add it to the subsystem
 276                xbar = L2XBar()
 277                subsys.xbar = xbar
 278                xbar.master = next_cache.cpu_side
 279                for tester in testers:
 280                     tester.port = xbar.slave
 281           else:
 282                # Single tester
 283                testers[0].port = next_cache.cpu_side
 284
 285 # Top level call to create the cache hierarchy, bottom up
 286 make_cache_level(cachespec, cache_proto, len(cachespec), None)
 287
 288 # Connect the lowest level crossbar to the memory
 289 last_subsys = getattr(system, 'l%dsubsys0' % len(cachespec))
 290 last_subsys.xbar.master = system.physmem.port
 291
 292 root = Root(full_system = False, system = system)
 293 if options.atomic:
 294     root.system.mem_mode = 'atomic'
 295 else:
 296     root.system.mem_mode = 'timing'
 297
 298 # The system port is never used in the tester so merely connect it
 299 # to avoid problems
 300 root.system.system_port = last_subsys.xbar.slave
 301
 302 # Instantiate configuration
 303 m5.instantiate()
 304
 305 # Simulate until program terminates
 306 exit_event = m5.simulate(options.maxtick)
 307
 308 print 'Exiting @ tick', m5.curTick(), 'because', exit_event.getCause()