apu_se.py revision 11700:7d4d424c9f17
1# 2# Copyright (c) 2015 Advanced Micro Devices, Inc. 3# All rights reserved. 4# 5# For use for simulation and test purposes only 6# 7# Redistribution and use in source and binary forms, with or without 8# modification, are permitted provided that the following conditions are met: 9# 10# 1. Redistributions of source code must retain the above copyright notice, 11# this list of conditions and the following disclaimer. 12# 13# 2. Redistributions in binary form must reproduce the above copyright notice, 14# this list of conditions and the following disclaimer in the documentation 15# and/or other materials provided with the distribution. 16# 17# 3. Neither the name of the copyright holder nor the names of its contributors 18# may be used to endorse or promote products derived from this software 19# without specific prior written permission. 20# 21# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 22# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 25# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31# POSSIBILITY OF SUCH DAMAGE. 32# 33# Author: Sooraj Puthoor 34# 35 36import optparse, os, re 37import math 38import glob 39import inspect 40 41import m5 42from m5.objects import * 43from m5.util import addToPath 44 45addToPath('../') 46 47from ruby import Ruby 48 49from common import Options 50from common import Simulation 51from common import GPUTLBOptions, GPUTLBConfig 52 53########################## Script Options ######################## 54def setOption(parser, opt_str, value = 1): 55 # check to make sure the option actually exists 56 if not parser.has_option(opt_str): 57 raise Exception("cannot find %s in list of possible options" % opt_str) 58 59 opt = parser.get_option(opt_str) 60 # set the value 61 exec("parser.values.%s = %s" % (opt.dest, value)) 62 63def getOption(parser, opt_str): 64 # check to make sure the option actually exists 65 if not parser.has_option(opt_str): 66 raise Exception("cannot find %s in list of possible options" % opt_str) 67 68 opt = parser.get_option(opt_str) 69 # get the value 70 exec("return_value = parser.values.%s" % opt.dest) 71 return return_value 72 73# Adding script options 74parser = optparse.OptionParser() 75Options.addCommonOptions(parser) 76Options.addSEOptions(parser) 77 78parser.add_option("--cpu-only-mode", action="store_true", default=False, 79 help="APU mode. Used to take care of problems in "\ 80 "Ruby.py while running APU protocols") 81parser.add_option("-k", "--kernel-files", 82 help="file(s) containing GPU kernel code (colon separated)") 83parser.add_option("-u", "--num-compute-units", type="int", default=1, 84 help="number of GPU compute units"), 85parser.add_option("--num-cp", type="int", default=0, 86 help="Number of GPU Command Processors (CP)") 87parser.add_option("--benchmark-root", help="Root of benchmark directory tree") 88 89# not super important now, but to avoid putting the number 4 everywhere, make 90# it an option/knob 91parser.add_option("--cu-per-sqc", type="int", default=4, help="number of CUs" \ 92 "sharing an SQC (icache, and thus icache TLB)") 93parser.add_option("--simds-per-cu", type="int", default=4, help="SIMD units" \ 94 "per CU") 95parser.add_option("--wf-size", type="int", default=64, 96 help="Wavefront size(in workitems)") 97parser.add_option("--sp-bypass-path-length", type="int", default=4, \ 98 help="Number of stages of bypass path in vector ALU for Single Precision ops") 99parser.add_option("--dp-bypass-path-length", type="int", default=4, \ 100 help="Number of stages of bypass path in vector ALU for Double Precision ops") 101# issue period per SIMD unit: number of cycles before issuing another vector 102parser.add_option("--issue-period", type="int", default=4, \ 103 help="Number of cycles per vector instruction issue period") 104parser.add_option("--glbmem-wr-bus-width", type="int", default=32, \ 105 help="VGPR to Coalescer (Global Memory) data bus width in bytes") 106parser.add_option("--glbmem-rd-bus-width", type="int", default=32, \ 107 help="Coalescer to VGPR (Global Memory) data bus width in bytes") 108# Currently we only support 1 local memory pipe 109parser.add_option("--shr-mem-pipes-per-cu", type="int", default=1, \ 110 help="Number of Shared Memory pipelines per CU") 111# Currently we only support 1 global memory pipe 112parser.add_option("--glb-mem-pipes-per-cu", type="int", default=1, \ 113 help="Number of Global Memory pipelines per CU") 114parser.add_option("--wfs-per-simd", type="int", default=10, help="Number of " \ 115 "WF slots per SIMD") 116 117parser.add_option("--vreg-file-size", type="int", default=2048, 118 help="number of physical vector registers per SIMD") 119parser.add_option("--bw-scalor", type="int", default=0, 120 help="bandwidth scalor for scalability analysis") 121parser.add_option("--CPUClock", type="string", default="2GHz", 122 help="CPU clock") 123parser.add_option("--GPUClock", type="string", default="1GHz", 124 help="GPU clock") 125parser.add_option("--cpu-voltage", action="store", type="string", 126 default='1.0V', 127 help = """CPU voltage domain""") 128parser.add_option("--gpu-voltage", action="store", type="string", 129 default='1.0V', 130 help = """CPU voltage domain""") 131parser.add_option("--CUExecPolicy", type="string", default="OLDEST-FIRST", 132 help="WF exec policy (OLDEST-FIRST, ROUND-ROBIN)") 133parser.add_option("--xact-cas-mode", action="store_true", 134 help="enable load_compare mode (transactional CAS)") 135parser.add_option("--SegFaultDebug",action="store_true", 136 help="checks for GPU seg fault before TLB access") 137parser.add_option("--FunctionalTLB",action="store_true", 138 help="Assumes TLB has no latency") 139parser.add_option("--LocalMemBarrier",action="store_true", 140 help="Barrier does not wait for writethroughs to complete") 141parser.add_option("--countPages", action="store_true", 142 help="Count Page Accesses and output in per-CU output files") 143parser.add_option("--TLB-prefetch", type="int", help = "prefetch depth for"\ 144 "TLBs") 145parser.add_option("--pf-type", type="string", help="type of prefetch: "\ 146 "PF_CU, PF_WF, PF_PHASE, PF_STRIDE") 147parser.add_option("--pf-stride", type="int", help="set prefetch stride") 148parser.add_option("--numLdsBanks", type="int", default=32, 149 help="number of physical banks per LDS module") 150parser.add_option("--ldsBankConflictPenalty", type="int", default=1, 151 help="number of cycles per LDS bank conflict") 152parser.add_option('--fast-forward-pseudo-op', action='store_true', 153 help = 'fast forward using kvm until the m5_switchcpu' 154 ' pseudo-op is encountered, then switch cpus. subsequent' 155 ' m5_switchcpu pseudo-ops will toggle back and forth') 156parser.add_option('--outOfOrderDataDelivery', action='store_true', 157 default=False, help='enable OoO data delivery in the GM' 158 ' pipeline') 159 160Ruby.define_options(parser) 161 162#add TLB options to the parser 163GPUTLBOptions.tlb_options(parser) 164 165(options, args) = parser.parse_args() 166 167# The GPU cache coherence protocols only work with the backing store 168setOption(parser, "--access-backing-store") 169 170# if benchmark root is specified explicitly, that overrides the search path 171if options.benchmark_root: 172 benchmark_path = [options.benchmark_root] 173else: 174 # Set default benchmark search path to current dir 175 benchmark_path = ['.'] 176 177########################## Sanity Check ######################## 178 179# Currently the gpu model requires ruby 180if buildEnv['PROTOCOL'] == 'None': 181 fatal("GPU model requires ruby") 182 183# Currently the gpu model requires only timing or detailed CPU 184if not (options.cpu_type == "timing" or 185 options.cpu_type == "detailed"): 186 fatal("GPU model requires timing or detailed CPU") 187 188# This file can support multiple compute units 189assert(options.num_compute_units >= 1) 190 191# Currently, the sqc (I-Cache of GPU) is shared by 192# multiple compute units(CUs). The protocol works just fine 193# even if sqc is not shared. Overriding this option here 194# so that the user need not explicitly set this (assuming 195# sharing sqc is the common usage) 196n_cu = options.num_compute_units 197num_sqc = int(math.ceil(float(n_cu) / options.cu_per_sqc)) 198options.num_sqc = num_sqc # pass this to Ruby 199 200########################## Creating the GPU system ######################## 201# shader is the GPU 202shader = Shader(n_wf = options.wfs_per_simd, 203 clk_domain = SrcClockDomain( 204 clock = options.GPUClock, 205 voltage_domain = VoltageDomain( 206 voltage = options.gpu_voltage))) 207 208# GPU_RfO(Read For Ownership) implements SC/TSO memory model. 209# Other GPU protocols implement release consistency at GPU side. 210# So, all GPU protocols other than GPU_RfO should make their writes 211# visible to the global memory and should read from global memory 212# during kernal boundary. The pipeline initiates(or do not initiate) 213# the acquire/release operation depending on this impl_kern_boundary_sync 214# flag. This flag=true means pipeline initiates a acquire/release operation 215# at kernel boundary. 216if buildEnv['PROTOCOL'] == 'GPU_RfO': 217 shader.impl_kern_boundary_sync = False 218else: 219 shader.impl_kern_boundary_sync = True 220 221# Switching off per-lane TLB by default 222per_lane = False 223if options.TLB_config == "perLane": 224 per_lane = True 225 226# List of compute units; one GPU can have multiple compute units 227compute_units = [] 228for i in xrange(n_cu): 229 compute_units.append(ComputeUnit(cu_id = i, perLaneTLB = per_lane, 230 num_SIMDs = options.simds_per_cu, 231 wfSize = options.wf_size, 232 spbypass_pipe_length = options.sp_bypass_path_length, 233 dpbypass_pipe_length = options.dp_bypass_path_length, 234 issue_period = options.issue_period, 235 coalescer_to_vrf_bus_width = \ 236 options.glbmem_rd_bus_width, 237 vrf_to_coalescer_bus_width = \ 238 options.glbmem_wr_bus_width, 239 num_global_mem_pipes = \ 240 options.glb_mem_pipes_per_cu, 241 num_shared_mem_pipes = \ 242 options.shr_mem_pipes_per_cu, 243 n_wf = options.wfs_per_simd, 244 execPolicy = options.CUExecPolicy, 245 xactCasMode = options.xact_cas_mode, 246 debugSegFault = options.SegFaultDebug, 247 functionalTLB = options.FunctionalTLB, 248 localMemBarrier = options.LocalMemBarrier, 249 countPages = options.countPages, 250 localDataStore = \ 251 LdsState(banks = options.numLdsBanks, 252 bankConflictPenalty = \ 253 options.ldsBankConflictPenalty), 254 out_of_order_data_delivery = 255 options.outOfOrderDataDelivery)) 256 wavefronts = [] 257 vrfs = [] 258 for j in xrange(options.simds_per_cu): 259 for k in xrange(shader.n_wf): 260 wavefronts.append(Wavefront(simdId = j, wf_slot_id = k, 261 wfSize = options.wf_size)) 262 vrfs.append(VectorRegisterFile(simd_id=j, 263 num_regs_per_simd=options.vreg_file_size)) 264 compute_units[-1].wavefronts = wavefronts 265 compute_units[-1].vector_register_file = vrfs 266 if options.TLB_prefetch: 267 compute_units[-1].prefetch_depth = options.TLB_prefetch 268 compute_units[-1].prefetch_prev_type = options.pf_type 269 270 # attach the LDS and the CU to the bus (actually a Bridge) 271 compute_units[-1].ldsPort = compute_units[-1].ldsBus.slave 272 compute_units[-1].ldsBus.master = compute_units[-1].localDataStore.cuPort 273 274# Attach compute units to GPU 275shader.CUs = compute_units 276 277########################## Creating the CPU system ######################## 278options.num_cpus = options.num_cpus 279 280# The shader core will be whatever is after the CPU cores are accounted for 281shader_idx = options.num_cpus 282 283# The command processor will be whatever is after the shader is accounted for 284cp_idx = shader_idx + 1 285cp_list = [] 286 287# List of CPUs 288cpu_list = [] 289 290CpuClass, mem_mode = Simulation.getCPUClass(options.cpu_type) 291if CpuClass == AtomicSimpleCPU: 292 fatal("AtomicSimpleCPU is not supported") 293if mem_mode != 'timing': 294 fatal("Only the timing memory mode is supported") 295shader.timing = True 296 297if options.fast_forward and options.fast_forward_pseudo_op: 298 fatal("Cannot fast-forward based both on the number of instructions and" 299 " on pseudo-ops") 300fast_forward = options.fast_forward or options.fast_forward_pseudo_op 301 302if fast_forward: 303 FutureCpuClass, future_mem_mode = CpuClass, mem_mode 304 305 CpuClass = X86KvmCPU 306 mem_mode = 'atomic_noncaching' 307 # Leave shader.timing untouched, because its value only matters at the 308 # start of the simulation and because we require switching cpus 309 # *before* the first kernel launch. 310 311 future_cpu_list = [] 312 313 # Initial CPUs to be used during fast-forwarding. 314 for i in xrange(options.num_cpus): 315 cpu = CpuClass(cpu_id = i, 316 clk_domain = SrcClockDomain( 317 clock = options.CPUClock, 318 voltage_domain = VoltageDomain( 319 voltage = options.cpu_voltage))) 320 cpu_list.append(cpu) 321 322 if options.fast_forward: 323 cpu.max_insts_any_thread = int(options.fast_forward) 324 325if fast_forward: 326 MainCpuClass = FutureCpuClass 327else: 328 MainCpuClass = CpuClass 329 330# CPs to be used throughout the simulation. 331for i in xrange(options.num_cp): 332 cp = MainCpuClass(cpu_id = options.num_cpus + i, 333 clk_domain = SrcClockDomain( 334 clock = options.CPUClock, 335 voltage_domain = VoltageDomain( 336 voltage = options.cpu_voltage))) 337 cp_list.append(cp) 338 339# Main CPUs (to be used after fast-forwarding if fast-forwarding is specified). 340for i in xrange(options.num_cpus): 341 cpu = MainCpuClass(cpu_id = i, 342 clk_domain = SrcClockDomain( 343 clock = options.CPUClock, 344 voltage_domain = VoltageDomain( 345 voltage = options.cpu_voltage))) 346 if fast_forward: 347 cpu.switched_out = True 348 future_cpu_list.append(cpu) 349 else: 350 cpu_list.append(cpu) 351 352########################## Creating the GPU dispatcher ######################## 353# Dispatcher dispatches work from host CPU to GPU 354host_cpu = cpu_list[0] 355dispatcher = GpuDispatcher() 356 357########################## Create and assign the workload ######################## 358# Check for rel_path in elements of base_list using test, returning 359# the first full path that satisfies test 360def find_path(base_list, rel_path, test): 361 for base in base_list: 362 if not base: 363 # base could be None if environment var not set 364 continue 365 full_path = os.path.join(base, rel_path) 366 if test(full_path): 367 return full_path 368 fatal("%s not found in %s" % (rel_path, base_list)) 369 370def find_file(base_list, rel_path): 371 return find_path(base_list, rel_path, os.path.isfile) 372 373executable = find_path(benchmark_path, options.cmd, os.path.exists) 374# it's common for a benchmark to be in a directory with the same 375# name as the executable, so we handle that automatically 376if os.path.isdir(executable): 377 benchmark_path = [executable] 378 executable = find_file(benchmark_path, options.cmd) 379if options.kernel_files: 380 kernel_files = [find_file(benchmark_path, f) 381 for f in options.kernel_files.split(':')] 382else: 383 # if kernel_files is not set, see if there's a unique .asm file 384 # in the same directory as the executable 385 kernel_path = os.path.dirname(executable) 386 kernel_files = glob.glob(os.path.join(kernel_path, '*.asm')) 387 if kernel_files: 388 print "Using GPU kernel code file(s)", ",".join(kernel_files) 389 else: 390 fatal("Can't locate kernel code (.asm) in " + kernel_path) 391 392# OpenCL driver 393driver = ClDriver(filename="hsa", codefile=kernel_files) 394for cpu in cpu_list: 395 cpu.workload = LiveProcess(executable = executable, 396 cmd = [options.cmd] + options.options.split(), 397 drivers = [driver]) 398for cp in cp_list: 399 cp.workload = host_cpu.workload 400 401if fast_forward: 402 for i in xrange(len(future_cpu_list)): 403 future_cpu_list[i].workload = cpu_list[i].workload 404 405########################## Create the overall system ######################## 406# List of CPUs that must be switched when moving between KVM and simulation 407if fast_forward: 408 switch_cpu_list = \ 409 [(cpu_list[i], future_cpu_list[i]) for i in xrange(options.num_cpus)] 410 411# Full list of processing cores in the system. Note that 412# dispatcher is also added to cpu_list although it is 413# not a processing element 414cpu_list = cpu_list + [shader] + cp_list + [dispatcher] 415 416# creating the overall system 417# notice the cpu list is explicitly added as a parameter to System 418system = System(cpu = cpu_list, 419 mem_ranges = [AddrRange(options.mem_size)], 420 cache_line_size = options.cacheline_size, 421 mem_mode = mem_mode) 422if fast_forward: 423 system.future_cpu = future_cpu_list 424system.voltage_domain = VoltageDomain(voltage = options.sys_voltage) 425system.clk_domain = SrcClockDomain(clock = options.sys_clock, 426 voltage_domain = system.voltage_domain) 427 428if fast_forward: 429 have_kvm_support = 'BaseKvmCPU' in globals() 430 if have_kvm_support and buildEnv['TARGET_ISA'] == "x86": 431 system.vm = KvmVM() 432 for i in xrange(len(host_cpu.workload)): 433 host_cpu.workload[i].useArchPT = True 434 host_cpu.workload[i].kvmInSE = True 435 else: 436 fatal("KvmCPU can only be used in SE mode with x86") 437 438# configure the TLB hierarchy 439GPUTLBConfig.config_tlb_hierarchy(options, system, shader_idx) 440 441# create Ruby system 442system.piobus = IOXBar(width=32, response_latency=0, 443 frontend_latency=0, forward_latency=0) 444Ruby.create_system(options, None, system) 445system.ruby.clk_domain = SrcClockDomain(clock = options.ruby_clock, 446 voltage_domain = system.voltage_domain) 447 448# attach the CPU ports to Ruby 449for i in range(options.num_cpus): 450 ruby_port = system.ruby._cpu_ports[i] 451 452 # Create interrupt controller 453 system.cpu[i].createInterruptController() 454 455 # Connect cache port's to ruby 456 system.cpu[i].icache_port = ruby_port.slave 457 system.cpu[i].dcache_port = ruby_port.slave 458 459 ruby_port.mem_master_port = system.piobus.slave 460 if buildEnv['TARGET_ISA'] == "x86": 461 system.cpu[i].interrupts[0].pio = system.piobus.master 462 system.cpu[i].interrupts[0].int_master = system.piobus.slave 463 system.cpu[i].interrupts[0].int_slave = system.piobus.master 464 if fast_forward: 465 system.cpu[i].itb.walker.port = ruby_port.slave 466 system.cpu[i].dtb.walker.port = ruby_port.slave 467 468# attach CU ports to Ruby 469# Because of the peculiarities of the CP core, you may have 1 CPU but 2 470# sequencers and thus 2 _cpu_ports created. Your GPUs shouldn't be 471# hooked up until after the CP. To make this script generic, figure out 472# the index as below, but note that this assumes there is one sequencer 473# per compute unit and one sequencer per SQC for the math to work out 474# correctly. 475gpu_port_idx = len(system.ruby._cpu_ports) \ 476 - options.num_compute_units - options.num_sqc 477gpu_port_idx = gpu_port_idx - options.num_cp * 2 478 479wavefront_size = options.wf_size 480for i in xrange(n_cu): 481 # The pipeline issues wavefront_size number of uncoalesced requests 482 # in one GPU issue cycle. Hence wavefront_size mem ports. 483 for j in xrange(wavefront_size): 484 system.cpu[shader_idx].CUs[i].memory_port[j] = \ 485 system.ruby._cpu_ports[gpu_port_idx].slave[j] 486 gpu_port_idx += 1 487 488for i in xrange(n_cu): 489 if i > 0 and not i % options.cu_per_sqc: 490 print "incrementing idx on ", i 491 gpu_port_idx += 1 492 system.cpu[shader_idx].CUs[i].sqc_port = \ 493 system.ruby._cpu_ports[gpu_port_idx].slave 494gpu_port_idx = gpu_port_idx + 1 495 496# attach CP ports to Ruby 497for i in xrange(options.num_cp): 498 system.cpu[cp_idx].createInterruptController() 499 system.cpu[cp_idx].dcache_port = \ 500 system.ruby._cpu_ports[gpu_port_idx + i * 2].slave 501 system.cpu[cp_idx].icache_port = \ 502 system.ruby._cpu_ports[gpu_port_idx + i * 2 + 1].slave 503 system.cpu[cp_idx].interrupts[0].pio = system.piobus.master 504 system.cpu[cp_idx].interrupts[0].int_master = system.piobus.slave 505 system.cpu[cp_idx].interrupts[0].int_slave = system.piobus.master 506 cp_idx = cp_idx + 1 507 508# connect dispatcher to the system.piobus 509dispatcher.pio = system.piobus.master 510dispatcher.dma = system.piobus.slave 511 512################# Connect the CPU and GPU via GPU Dispatcher ################### 513# CPU rings the GPU doorbell to notify a pending task 514# using this interface. 515# And GPU uses this interface to notify the CPU of task completion 516# The communcation happens through emulated driver. 517 518# Note this implicit setting of the cpu_pointer, shader_pointer and tlb array 519# parameters must be after the explicit setting of the System cpu list 520if fast_forward: 521 shader.cpu_pointer = future_cpu_list[0] 522 dispatcher.cpu = future_cpu_list[0] 523else: 524 shader.cpu_pointer = host_cpu 525 dispatcher.cpu = host_cpu 526dispatcher.shader_pointer = shader 527dispatcher.cl_driver = driver 528 529########################## Start simulation ######################## 530 531root = Root(system=system, full_system=False) 532m5.ticks.setGlobalFrequency('1THz') 533if options.abs_max_tick: 534 maxtick = options.abs_max_tick 535else: 536 maxtick = m5.MaxTick 537 538# Benchmarks support work item annotations 539Simulation.setWorkCountOptions(system, options) 540 541# Checkpointing is not supported by APU model 542if (options.checkpoint_dir != None or 543 options.checkpoint_restore != None): 544 fatal("Checkpointing not supported by apu model") 545 546checkpoint_dir = None 547m5.instantiate(checkpoint_dir) 548 549# Map workload to this address space 550host_cpu.workload[0].map(0x10000000, 0x200000000, 4096) 551 552if options.fast_forward: 553 print "Switch at instruction count: %d" % \ 554 cpu_list[0].max_insts_any_thread 555 556exit_event = m5.simulate(maxtick) 557 558if options.fast_forward: 559 if exit_event.getCause() == "a thread reached the max instruction count": 560 m5.switchCpus(system, switch_cpu_list) 561 print "Switched CPUS @ tick %s" % (m5.curTick()) 562 m5.stats.reset() 563 exit_event = m5.simulate(maxtick - m5.curTick()) 564elif options.fast_forward_pseudo_op: 565 while exit_event.getCause() == "switchcpu": 566 # If we are switching *to* kvm, then the current stats are meaningful 567 # Note that we don't do any warmup by default 568 if type(switch_cpu_list[0][0]) == FutureCpuClass: 569 print "Dumping stats..." 570 m5.stats.dump() 571 m5.switchCpus(system, switch_cpu_list) 572 print "Switched CPUS @ tick %s" % (m5.curTick()) 573 m5.stats.reset() 574 # This lets us switch back and forth without keeping a counter 575 switch_cpu_list = [(x[1], x[0]) for x in switch_cpu_list] 576 exit_event = m5.simulate(maxtick - m5.curTick()) 577 578print "Ticks:", m5.curTick() 579print 'Exiting because ', exit_event.getCause() 580sys.exit(exit_event.getCode()) 581