xref: /gem5/configs/dram/low_power_sweep.py

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# Authors: Radhika Jagtap
#          Andreas Hansson

import argparse

import m5
from m5.objects import *
from m5.util import addToPath
from m5.stats import periodicStatDump

addToPath(os.getcwd() + '/configs/common')
import MemConfig

# This script aims at triggering low power state transitions in the DRAM
# controller. The traffic generator is used in DRAM mode and traffic
# states target a different levels of bank utilization and strides.
# At the end after sweeping through bank utilization and strides, we go
# through an idle state with no requests to enforce self-refresh.

parser = argparse.ArgumentParser(
  formatter_class=argparse.ArgumentDefaultsHelpFormatter)

# Use a single-channel DDR4-2400 in 16x4 configuration by default
parser.add_argument("--mem-type", default="DDR4_2400_16x4",
                    choices=MemConfig.mem_names(),
                    help = "type of memory to use")

parser.add_argument("--mem-ranks", "-r", type=int, default=1,
                    help = "Number of ranks to iterate across")

parser.add_argument("--page-policy", "-p",
                    choices=["close_adaptive", "open_adaptive"],
                    default="close_adaptive", help="controller page policy")

parser.add_argument("--itt-list", "-t", default="1 20 100",
                    help="a list of multipliers for the max value of itt, " \
                    "e.g. \"1 20 100\"")

parser.add_argument("--rd-perc", type=int, default=100,
                    help = "Percentage of read commands")

parser.add_argument("--addr-map", type=int, default=1,
                    help = "0: RoCoRaBaCh; 1: RoRaBaCoCh/RoRaBaChCo")

parser.add_argument("--idle-end", type=int, default=50000000,
                    help = "time in ps of an idle period at the end ")

args = parser.parse_args()

# Start with the system itself, using a multi-layer 2.0 GHz
# crossbar, delivering 64 bytes / 3 cycles (one header cycle)
# which amounts to 42.7 GByte/s per layer and thus per port.
system = System(membus = IOXBar(width = 32))
system.clk_domain = SrcClockDomain(clock = '2.0GHz',
                                   voltage_domain =
                                   VoltageDomain(voltage = '1V'))

# We are fine with 256 MB memory for now.
mem_range = AddrRange('256MB')
# Start address is 0
system.mem_ranges = [mem_range]

# Do not worry about reserving space for the backing store
system.mmap_using_noreserve = True

# Force a single channel to match the assumptions in the DRAM traffic
# generator
args.mem_channels = 1
args.external_memory_system = 0
args.tlm_memory = 0
args.elastic_trace_en = 0
MemConfig.config_mem(args, system)

# Sanity check for memory controller class.
if not isinstance(system.mem_ctrls[0], m5.objects.DRAMCtrl):
    fatal("This script assumes the memory is a DRAMCtrl subclass")

# There is no point slowing things down by saving any data.
system.mem_ctrls[0].null = True

# Set the address mapping based on input argument
# Default to RoRaBaCoCh
if args.addr_map == 0:
   system.mem_ctrls[0].addr_mapping = "RoCoRaBaCh"
elif args.addr_map == 1:
   system.mem_ctrls[0].addr_mapping = "RoRaBaCoCh"
else:
    fatal("Did not specify a valid address map argument")

system.mem_ctrls[0].page_policy = args.page_policy

# We create a traffic generator state for each param combination we want to
# test. Each traffic generator state is specified in the config file and the
# generator remains in the state for specific period. This period is 0.25 ms.
# Stats are dumped and reset at the state transition.
period = 250000000

# We specify the states in a config file input to the traffic generator.
cfg_file_name = "configs/dram/lowp_sweep.cfg"
cfg_file = open(cfg_file_name, 'w')

# Get the number of banks
nbr_banks = int(system.mem_ctrls[0].banks_per_rank.value)

# determine the burst size in bytes
burst_size = int((system.mem_ctrls[0].devices_per_rank.value *
                  system.mem_ctrls[0].device_bus_width.value *
                  system.mem_ctrls[0].burst_length.value) / 8)

# next, get the page size in bytes (the rowbuffer size is already in bytes)
page_size = system.mem_ctrls[0].devices_per_rank.value * \
    system.mem_ctrls[0].device_rowbuffer_size.value

# Inter-request delay should be such that we can hit as many transitions
# to/from low power states as possible to. We provide a min and max itt to the
# traffic generator and it randomises in the range. The parameter is in
# seconds and we need it in ticks (ps).
itt_min = system.mem_ctrls[0].tBURST.value * 1000000000000

#The itt value when set to (tRAS + tRP + tCK) covers the case where
# a read command is delayed beyond the delay from ACT to PRE_PDN entry of the
# previous command. For write command followed by precharge, this delay
# between a write and power down entry will be tRCD + tCL + tWR + tRP + tCK.
# As we use this delay as a unit and create multiples of it as bigger delays
# for the sweep, this parameter works for reads, writes and mix of them.
pd_entry_time = (system.mem_ctrls[0].tRAS.value +
                 system.mem_ctrls[0].tRP.value +
                 system.mem_ctrls[0].tCK.value) * 1000000000000

# We sweep itt max using the multipliers specified by the user.
itt_max_str = args.itt_list.strip().split()
itt_max_multiples = map(lambda x : int(x), itt_max_str)
if len(itt_max_multiples) == 0:
    fatal("String for itt-max-list detected empty\n")

itt_max_values = map(lambda m : pd_entry_time * m, itt_max_multiples)

# Generate request addresses in the entire range, assume we start at 0
max_addr = mem_range.end

# For max stride, use min of the page size and 512 bytes as that should be
# more than enough
max_stride = min(512, page_size)
mid_stride = 4 * burst_size
stride_values = [burst_size, mid_stride, max_stride]

# be selective about bank utilization instead of going from 1 to the number of
# banks
bank_util_values = [1, int(nbr_banks/2), nbr_banks]

# Next we create the config file, but first a comment
cfg_file.write("""# STATE state# period mode=DRAM
# read_percent start_addr end_addr req_size min_itt max_itt data_limit
# stride_size page_size #banks #banks_util addr_map #ranks\n""")

nxt_state = 0
for itt_max in itt_max_values:
    for bank in bank_util_values:
        for stride_size in stride_values:
            cfg_file.write("STATE %d %d %s %d 0 %d %d "
                           "%d %d %d %d %d %d %d %d %d\n" %
                           (nxt_state, period, "DRAM", args.rd_perc, max_addr,
                            burst_size, itt_min, itt_max, 0, stride_size,
                            page_size, nbr_banks, bank, args.addr_map,
                            args.mem_ranks))
            nxt_state = nxt_state + 1

# State for idle period
idle_period = args.idle_end
cfg_file.write("STATE %d %d IDLE\n" % (nxt_state, idle_period))

# Init state is state 0
cfg_file.write("INIT 0\n")

# Go through the states one by one
for state in range(1, nxt_state + 1):
    cfg_file.write("TRANSITION %d %d 1\n" % (state - 1, state))

# Transition from last state to itself to not break the probability math
cfg_file.write("TRANSITION %d %d 1\n" % (nxt_state, nxt_state))
cfg_file.close()

# create a traffic generator, and point it to the file we just created
system.tgen = TrafficGen(config_file = cfg_file_name)

# add a communication monitor
system.monitor = CommMonitor()

# connect the traffic generator to the bus via a communication monitor
system.tgen.port = system.monitor.slave
system.monitor.master = system.membus.slave

# connect the system port even if it is not used in this example
system.system_port = system.membus.slave

# every period, dump and reset all stats
periodicStatDump(period)

root = Root(full_system = False, system = system)
root.system.mem_mode = 'timing'

m5.instantiate()

# Simulate for exactly as long as it takes to go through all the states
# This is why sim exists.
m5.simulate(nxt_state * period + idle_period)
print "--- Done DRAM low power sweep ---"
print "Fixed params - "
print "\tburst: %d, banks: %d, max stride: %d, itt min: %s ns" %  \
  (burst_size, nbr_banks, max_stride, itt_min)
print "Swept params - "
print "\titt max multiples input:", itt_max_multiples
print "\titt max values", itt_max_values
print "\tbank utilization values", bank_util_values
print "\tstride values:", stride_values
print "Traffic gen config file:", cfg_file_name