gem5/configs/common/MemConfig.py
Andreas Hansson bf2f178f85 mem: Add a wrapped DRAMSim2 memory controller
This patch adds DRAMSim2 as a memory controller by wrapping the
external library and creating a sublass of AbstractMemory that bridges
between the semantics of gem5 and the DRAMSim2 interface.

The DRAMSim2 wrapper extracts the clock period from the config
file. There is no way of extracting this information from DRAMSim2
itself, so we simply read the same config file and get it from there.

To properly model the response queue, the wrapper keeps track of how
many transactions are in the actual controller, and how many are
stacking up waiting to be sent back as responses (in the wrapper). The
latter requires us to move away from the queued port and manage the
packets ourselves. This is due to DRAMSim2 not having any flow control
on the response path.

DRAMSim2 assumes that the transactions it is given are matching the
burst size of the choosen memory. The wrapper checks to ensure the
cache line size of the system matches the burst size of DRAMSim2 as
there are currently no provisions to split the system requests. In
theory we could allow a cache line size smaller than the burst size,
but that would lead to inefficient use of the DRAM, so for not we
fatal also in this case.
2014-02-18 05:50:53 -05:00

194 lines
7.6 KiB
Python

# Copyright (c) 2013 ARM Limited
# All rights reserved.
#
# The license below extends only to copyright in the software and shall
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# property including but not limited to intellectual property relating
# to a hardware implementation of the functionality of the software
# licensed hereunder. You may use the software subject to the license
# terms below provided that you ensure that this notice is replicated
# unmodified and in its entirety in all distributions of the software,
# modified or unmodified, in source code or in binary form.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
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# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: Andreas Sandberg
# Andreas Hansson
import m5.objects
import inspect
import sys
from textwrap import TextWrapper
# Dictionary of mapping names of real memory controller models to
# classes.
_mem_classes = {}
# Memory aliases. We make sure they exist before we add them to the
# fina; list. A target may be specified as a tuple, in which case the
# first available memory controller model in the tuple will be used.
_mem_aliases_all = [
("simple_mem", "SimpleMemory"),
("ddr3_1600_x64", "DDR3_1600_x64"),
("lpddr2_s4_1066_x32", "LPDDR2_S4_1066_x32"),
("lpddr3_1600_x32", "LPDDR3_1600_x32"),
("wio_200_x128", "WideIO_200_x128"),
("dramsim2", "DRAMSim2")
]
# Filtered list of aliases. Only aliases for existing memory
# controllers exist in this list.
_mem_aliases = {}
def is_mem_class(cls):
"""Determine if a class is a memory controller that can be instantiated"""
# We can't use the normal inspect.isclass because the ParamFactory
# and ProxyFactory classes have a tendency to confuse it.
try:
return issubclass(cls, m5.objects.AbstractMemory) and \
not cls.abstract
except TypeError:
return False
def get(name):
"""Get a memory class from a user provided class name or alias."""
real_name = _mem_aliases.get(name, name)
try:
mem_class = _mem_classes[real_name]
return mem_class
except KeyError:
print "%s is not a valid memory controller." % (name,)
sys.exit(1)
def print_mem_list():
"""Print a list of available memory classes including their aliases."""
print "Available memory classes:"
doc_wrapper = TextWrapper(initial_indent="\t\t", subsequent_indent="\t\t")
for name, cls in _mem_classes.items():
print "\t%s" % name
# Try to extract the class documentation from the class help
# string.
doc = inspect.getdoc(cls)
if doc:
for line in doc_wrapper.wrap(doc):
print line
if _mem_aliases:
print "\nMemory aliases:"
for alias, target in _mem_aliases.items():
print "\t%s => %s" % (alias, target)
def mem_names():
"""Return a list of valid memory names."""
return _mem_classes.keys() + _mem_aliases.keys()
# Add all memory controllers in the object hierarchy.
for name, cls in inspect.getmembers(m5.objects, is_mem_class):
_mem_classes[name] = cls
for alias, target in _mem_aliases_all:
if isinstance(target, tuple):
# Some aliases contain a list of memory controller models
# sorted in priority order. Use the first target that's
# available.
for t in target:
if t in _mem_classes:
_mem_aliases[alias] = t
break
elif target in _mem_classes:
# Normal alias
_mem_aliases[alias] = target
def config_mem(options, system):
"""
Create the memory controllers based on the options and attach them.
If requested, we make a multi-channel configuration of the
selected memory controller class by creating multiple instances of
the specific class. The individual controllers have their
parameters set such that the address range is interleaved between
them.
"""
nbr_mem_ctrls = options.mem_channels
import math
from m5.util import fatal
intlv_bits = int(math.log(nbr_mem_ctrls, 2))
if 2 ** intlv_bits != nbr_mem_ctrls:
fatal("Number of memory channels must be a power of 2")
cls = get(options.mem_type)
mem_ctrls = []
# The default behaviour is to interleave on cache line granularity
cache_line_bit = int(math.log(system.cache_line_size.value, 2)) - 1
intlv_low_bit = cache_line_bit
# For every range (most systems will only have one), create an
# array of controllers and set their parameters to match their
# address mapping in the case of a DRAM
for r in system.mem_ranges:
for i in xrange(nbr_mem_ctrls):
# Create an instance so we can figure out the address
# mapping and row-buffer size
ctrl = cls()
# Only do this for DRAMs
if issubclass(cls, m5.objects.SimpleDRAM):
# Inform each controller how many channels to account
# for
ctrl.channels = nbr_mem_ctrls
# If the channel bits are appearing after the column
# bits, we need to add the appropriate number of bits
# for the row buffer size
if ctrl.addr_mapping.value == 'RaBaChCo':
# This computation only really needs to happen
# once, but as we rely on having an instance we
# end up having to repeat it for each and every
# one
rowbuffer_size = ctrl.device_rowbuffer_size.value * \
ctrl.devices_per_rank.value
intlv_low_bit = int(math.log(rowbuffer_size, 2)) - 1
# We got all we need to configure the appropriate address
# range
ctrl.range = m5.objects.AddrRange(r.start, size = r.size(),
intlvHighBit = \
intlv_low_bit + intlv_bits,
intlvBits = intlv_bits,
intlvMatch = i)
mem_ctrls.append(ctrl)
system.mem_ctrls = mem_ctrls
# Connect the controllers to the membus
for i in xrange(len(system.mem_ctrls)):
system.mem_ctrls[i].port = system.membus.master