gem5/configs/example/memtest.py
Andreas Hansson 0d32940711 Bus: Split the bus into a non-coherent and coherent bus
This patch introduces a class hierarchy of buses, a non-coherent one,
and a coherent one, splitting the existing bus functionality. By doing
so it also enables further specialisation of the two types of buses.

A non-coherent bus connects a number of non-snooping masters and
slaves, and routes the request and response packets based on the
address. The request packets issued by the master connected to a
non-coherent bus could still snoop in caches attached to a coherent
bus, as is the case with the I/O bus and memory bus in most system
configurations. No snoops will, however, reach any master on the
non-coherent bus itself. The non-coherent bus can be used as a
template for modelling PCI, PCIe, and non-coherent AMBA and OCP buses,
and is typically used for the I/O buses.

A coherent bus connects a number of (potentially) snooping masters and
slaves, and routes the request and response packets based on the
address, and also forwards all requests to the snoopers and deals with
the snoop responses. The coherent bus can be used as a template for
modelling QPI, HyperTransport, ACE and coherent OCP buses, and is
typically used for the L1-to-L2 buses and as the main system
interconnect.

The configuration scripts are updated to use a NoncoherentBus for all
peripheral and I/O buses.

A bit of minor tidying up has also been done.

--HG--
rename : src/mem/bus.cc => src/mem/coherent_bus.cc
rename : src/mem/bus.hh => src/mem/coherent_bus.hh
rename : src/mem/bus.cc => src/mem/noncoherent_bus.cc
rename : src/mem/bus.hh => src/mem/noncoherent_bus.hh
2012-05-31 13:30:04 -04:00

199 lines
7.3 KiB
Python

# Copyright (c) 2006-2007 The Regents of The University of Michigan
# All rights reserved.
#
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# 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
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# 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
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# (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: Ron Dreslinski
import optparse
import sys
import m5
from m5.objects import *
parser = optparse.OptionParser()
parser.add_option("-a", "--atomic", action="store_true",
help="Use atomic (non-timing) mode")
parser.add_option("-b", "--blocking", action="store_true",
help="Use blocking caches")
parser.add_option("-l", "--maxloads", metavar="N", default=0,
help="Stop after N loads")
parser.add_option("-m", "--maxtick", type="int", default=m5.MaxTick,
metavar="T",
help="Stop after T ticks")
#
# The "tree" specification is a colon-separated list of one or more
# integers. The first integer is the number of caches/testers
# connected directly to main memory. The last integer in the list is
# the number of testers associated with the uppermost level of memory
# (L1 cache, if there are caches, or main memory if no caches). Thus
# if there is only one integer, there are no caches, and the integer
# specifies the number of testers connected directly to main memory.
# The other integers (if any) specify the number of caches at each
# level of the hierarchy between.
#
# Examples:
#
# "2:1" Two caches connected to memory with a single tester behind each
# (single-level hierarchy, two testers total)
#
# "2:2:1" Two-level hierarchy, 2 L1s behind each of 2 L2s, 4 testers total
#
parser.add_option("-t", "--treespec", type="string", default="8:1",
help="Colon-separated multilevel tree specification, "
"see script comments for details "
"[default: %default]")
parser.add_option("--force-bus", action="store_true",
help="Use bus between levels even with single cache")
parser.add_option("-f", "--functional", type="int", default=0,
metavar="PCT",
help="Target percentage of functional accesses "
"[default: %default]")
parser.add_option("-u", "--uncacheable", type="int", default=0,
metavar="PCT",
help="Target percentage of uncacheable accesses "
"[default: %default]")
parser.add_option("--progress", type="int", default=1000,
metavar="NLOADS",
help="Progress message interval "
"[default: %default]")
(options, args) = parser.parse_args()
if args:
print "Error: script doesn't take any positional arguments"
sys.exit(1)
block_size = 64
try:
treespec = [int(x) for x in options.treespec.split(':')]
numtesters = reduce(lambda x,y: x*y, treespec)
except:
print "Error parsing treespec option"
sys.exit(1)
if numtesters > block_size:
print "Error: Number of testers limited to %s because of false sharing" \
% (block_size)
sys.exit(1)
if len(treespec) < 1:
print "Error parsing treespec"
sys.exit(1)
# define prototype L1 cache
proto_l1 = BaseCache(size = '32kB', assoc = 4, block_size = block_size,
latency = '1ns', tgts_per_mshr = 8)
if options.blocking:
proto_l1.mshrs = 1
else:
proto_l1.mshrs = 4
# build a list of prototypes, one for each level of treespec, starting
# at the end (last entry is tester objects)
prototypes = [ MemTest(atomic=options.atomic, max_loads=options.maxloads,
percent_functional=options.functional,
percent_uncacheable=options.uncacheable,
progress_interval=options.progress) ]
# next comes L1 cache, if any
if len(treespec) > 1:
prototypes.insert(0, proto_l1)
# now add additional cache levels (if any) by scaling L1 params
for scale in treespec[:-2]:
# clone previous level and update params
prev = prototypes[0]
next = prev()
next.size = prev.size * scale
next.latency = prev.latency * 10
next.assoc = prev.assoc * scale
next.mshrs = prev.mshrs * scale
prototypes.insert(0, next)
# system simulated
system = System(funcmem = SimpleMemory(in_addr_map = False),
physmem = SimpleMemory(latency = "100ns"))
def make_level(spec, prototypes, attach_obj, attach_port):
fanout = spec[0]
parent = attach_obj # use attach obj as config parent too
if len(spec) > 1 and (fanout > 1 or options.force_bus):
port = getattr(attach_obj, attach_port)
new_bus = CoherentBus(clock="500MHz", width=16)
if (port.role == 'MASTER'):
new_bus.slave = port
attach_port = "master"
else:
new_bus.master = port
attach_port = "slave"
parent.cpu_side_bus = new_bus
attach_obj = new_bus
objs = [prototypes[0]() for i in xrange(fanout)]
if len(spec) > 1:
# we just built caches, more levels to go
parent.cache = objs
for cache in objs:
cache.mem_side = getattr(attach_obj, attach_port)
make_level(spec[1:], prototypes[1:], cache, "cpu_side")
else:
# we just built the MemTest objects
parent.cpu = objs
for t in objs:
t.test = getattr(attach_obj, attach_port)
t.functional = system.funcmem.port
make_level(treespec, prototypes, system.physmem, "port")
# -----------------------
# run simulation
# -----------------------
root = Root( full_system = False, system = system )
if options.atomic:
root.system.mem_mode = 'atomic'
else:
root.system.mem_mode = 'timing'
# The system port is never used in the tester so merely connect it
# to avoid problems
root.system.system_port = root.system.physmem.port
# Not much point in this being higher than the L1 latency
m5.ticks.setGlobalFrequency('1ns')
# instantiate configuration
m5.instantiate()
# simulate until program terminates
exit_event = m5.simulate(options.maxtick)
print 'Exiting @ tick', m5.curTick(), 'because', exit_event.getCause()