36dc93a5fa
This patch introduces a few subclasses to the CoherentXBar and NoncoherentXBar to distinguish the different uses in the system. We use the crossbar in a wide range of places: interfacing cores to the L2, as a system interconnect, connecting I/O and peripherals, etc. Needless to say, these crossbars have very different performance, and the clock frequency alone is not enough to distinguish these scenarios. Instead of trying to capture every possible case, this patch introduces dedicated subclasses for the three primary use-cases: L2XBar, SystemXBar and IOXbar. More can be added if needed, and the defaults can be overridden.
202 lines
7.7 KiB
Python
202 lines
7.7 KiB
Python
# Copyright (c) 2014 ARM Limited
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# All rights reserved.
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#
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# The license below extends only to copyright in the software and shall
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# not be construed as granting a license to any other intellectual
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# property including but not limited to intellectual property relating
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# to a hardware implementation of the functionality of the software
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# licensed hereunder. You may use the software subject to the license
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# terms below provided that you ensure that this notice is replicated
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# unmodified and in its entirety in all distributions of the software,
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# modified or unmodified, in source code or in binary form.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met: redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer;
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# redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution;
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# neither the name of the copyright holders nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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# Authors: Andreas Hansson
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import optparse
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import m5
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from m5.objects import *
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from m5.util import addToPath
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from m5.internal.stats import periodicStatDump
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addToPath('../common')
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import MemConfig
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# this script is helpful to sweep the efficiency of a specific memory
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# controller configuration, by varying the number of banks accessed,
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# and the sequential stride size (how many bytes per activate), and
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# observe what bus utilisation (bandwidth) is achieved
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parser = optparse.OptionParser()
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# Use a single-channel DDR3-1600 x64 by default
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parser.add_option("--mem-type", type="choice", default="ddr3_1600_x64",
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choices=MemConfig.mem_names(),
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help = "type of memory to use")
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parser.add_option("--ranks", "-r", type="int", default=1,
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help = "Number of ranks to iterate across")
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parser.add_option("--rd_perc", type="int", default=100,
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help = "Percentage of read commands")
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parser.add_option("--mode", type="choice", default="DRAM",
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choices=["DRAM", "DRAM_ROTATE"],
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help = "DRAM: Random traffic; \
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DRAM_ROTATE: Traffic rotating across banks and ranks")
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parser.add_option("--addr_map", type="int", default=1,
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help = "0: RoCoRaBaCh; 1: RoRaBaCoCh/RoRaBaChCo")
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(options, args) = parser.parse_args()
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if args:
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print "Error: script doesn't take any positional arguments"
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sys.exit(1)
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# at the moment we stay with the default open-adaptive page policy,
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# and address mapping
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# start with the system itself, using a multi-layer 1.5 GHz
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# crossbar, delivering 64 bytes / 5 cycles (one header cycle)
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# which amounts to 19.2 GByte/s per layer and thus per port
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system = System(membus = IOXBar(width = 16))
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system.clk_domain = SrcClockDomain(clock = '1.5GHz',
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voltage_domain =
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VoltageDomain(voltage = '1V'))
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# we are fine with 256 MB memory for now
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mem_range = AddrRange('256MB')
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system.mem_ranges = [mem_range]
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# force a single channel to match the assumptions in the DRAM traffic
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# generator
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options.mem_channels = 1
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MemConfig.config_mem(options, system)
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# the following assumes that we are using the native DRAM
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# controller, check to be sure
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if not isinstance(system.mem_ctrls[0], m5.objects.DRAMCtrl):
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fatal("This script assumes the memory is a DRAMCtrl subclass")
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# Set number of ranks based on input argument; default is 1 rank
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system.mem_ctrls[0].ranks_per_channel = options.ranks
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# Set the address mapping based on input argument
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# Default to RoRaBaCoCh
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if options.addr_map == 0:
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system.mem_ctrls[0].addr_mapping = "RoCoRaBaCh"
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elif options.addr_map == 1:
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system.mem_ctrls[0].addr_mapping = "RoRaBaCoCh"
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else:
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fatal("Did not specify a valid address map argument")
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# stay in each state for 0.25 ms, long enough to warm things up, and
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# short enough to avoid hitting a refresh
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period = 250000000
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# this is where we go off piste, and print the traffic generator
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# configuration that we will later use, crazy but it works
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cfg_file_name = "configs/dram/sweep.cfg"
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cfg_file = open(cfg_file_name, 'w')
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# stay in each state as long as the dump/reset period, use the entire
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# range, issue transactions of the right DRAM burst size, and match
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# the DRAM maximum bandwidth to ensure that it is saturated
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# get the number of banks
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nbr_banks = system.mem_ctrls[0].banks_per_rank.value
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# determine the burst length in bytes
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burst_size = int((system.mem_ctrls[0].devices_per_rank.value *
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system.mem_ctrls[0].device_bus_width.value *
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system.mem_ctrls[0].burst_length.value) / 8)
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# next, get the page size in bytes
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page_size = system.mem_ctrls[0].devices_per_rank.value * \
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system.mem_ctrls[0].device_rowbuffer_size.value
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# match the maximum bandwidth of the memory, the parameter is in ns
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# and we need it in ticks
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itt = system.mem_ctrls[0].tBURST.value * 1000000000000
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# assume we start at 0
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max_addr = mem_range.end
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# use min of the page size and 512 bytes as that should be more than
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# enough
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max_stride = min(512, page_size)
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# now we create the state by iterating over the stride size from burst
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# size to the max stride, and from using only a single bank up to the
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# number of banks available
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nxt_state = 0
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for bank in range(1, nbr_banks + 1):
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for stride_size in range(burst_size, max_stride + 1, burst_size):
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cfg_file.write("STATE %d %d %s %d 0 %d %d "
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"%d %d %d %d %d %d %d %d %d\n" %
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(nxt_state, period, options.mode, options.rd_perc,
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max_addr, burst_size, itt, itt, 0, stride_size,
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page_size, nbr_banks, bank, options.addr_map,
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options.ranks))
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nxt_state = nxt_state + 1
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cfg_file.write("INIT 0\n")
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# go through the states one by one
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for state in range(1, nxt_state):
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cfg_file.write("TRANSITION %d %d 1\n" % (state - 1, state))
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cfg_file.write("TRANSITION %d %d 1\n" % (nxt_state - 1, nxt_state - 1))
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cfg_file.close()
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# create a traffic generator, and point it to the file we just created
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system.tgen = TrafficGen(config_file = cfg_file_name)
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# add a communication monitor
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system.monitor = CommMonitor()
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# connect the traffic generator to the bus via a communication monitor
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system.tgen.port = system.monitor.slave
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system.monitor.master = system.membus.slave
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# connect the system port even if it is not used in this example
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system.system_port = system.membus.slave
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# every period, dump and reset all stats
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periodicStatDump(period)
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# run Forrest, run!
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root = Root(full_system = False, system = system)
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root.system.mem_mode = 'timing'
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m5.instantiate()
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m5.simulate(nxt_state * period)
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print "DRAM sweep with burst: %d, banks: %d, max stride: %d" % \
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(burst_size, nbr_banks, max_stride)
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