Files
gem5/configs/common/CpuConfig.py
Andreas Sandberg 719eb033fe cpu: Replace the fastmem with a new CPU model
The AtomicSimpleCPU used to be able to access memory directly to speed
up simulation if no caches are used. This is fine as long as no
switching between CPU models is required. In order to switch to a new
CPU model that requires caches, we currently need to checkpoint the
system and restore it into a new configuration. The new
'atomic_noncaching' memory mode provides a solution that avoids this
issue since caches are bypassed in this mode. This changeset removes
the old fastmem option from the AtomicSimpleCPU and introduces a new
CPU, NonCachingSimpleCPU, which derives from the AtomicSimpleCPU.

The NonCachingSimpleCPU uses the same mechanism as the AtomicSimpleCPU
used to use when accessing memory in when fastmem was enabled.

This changeset also introduces a new switcheroo test that tests
switching between a NonCachingSimpleCPU and a TimingSimpleCPU with
caches.

Change-Id: If01893f9b37528b14f530c11ce6f53c097582c21
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/12419
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
2018-09-12 09:25:26 +00:00

144 lines
5.7 KiB
Python

# Copyright (c) 2012, 2017-2018 ARM Limited
# All rights reserved.
#
# The license below extends only to copyright in the software and shall
# not be construed as granting a license to any other intellectual
# 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
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# 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
from __future__ import print_function
from m5 import fatal
import m5.objects
import inspect
import sys
from textwrap import TextWrapper
# Dictionary of mapping names of real CPU models to classes.
_cpu_classes = {}
def is_cpu_class(cls):
"""Determine if a class is a CPU 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.BaseCPU) and \
not cls.abstract and \
not issubclass(cls, m5.objects.CheckerCPU)
except (TypeError, AttributeError):
return False
def _cpu_subclass_tester(name):
cpu_class = getattr(m5.objects, name, None)
def tester(cls):
return cpu_class is not None and cls is not None and \
issubclass(cls, cpu_class)
return tester
is_kvm_cpu = _cpu_subclass_tester("BaseKvmCPU")
is_atomic_cpu = _cpu_subclass_tester("AtomicSimpleCPU")
def get(name):
"""Get a CPU class from a user provided class name or alias."""
try:
cpu_class = _cpu_classes[name]
return cpu_class
except KeyError:
print("%s is not a valid CPU model." % (name,))
sys.exit(1)
def print_cpu_list():
"""Print a list of available CPU classes including their aliases."""
print("Available CPU classes:")
doc_wrapper = TextWrapper(initial_indent="\t\t", subsequent_indent="\t\t")
for name, cls in _cpu_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)
def cpu_names():
"""Return a list of valid CPU names."""
return _cpu_classes.keys()
def config_etrace(cpu_cls, cpu_list, options):
if issubclass(cpu_cls, m5.objects.DerivO3CPU):
# Assign the same file name to all cpus for now. This must be
# revisited when creating elastic traces for multi processor systems.
for cpu in cpu_list:
# Attach the elastic trace probe listener. Set the protobuf trace
# file names. Set the dependency window size equal to the cpu it
# is attached to.
cpu.traceListener = m5.objects.ElasticTrace(
instFetchTraceFile = options.inst_trace_file,
dataDepTraceFile = options.data_trace_file,
depWindowSize = 3 * cpu.numROBEntries)
# Make the number of entries in the ROB, LQ and SQ very
# large so that there are no stalls due to resource
# limitation as such stalls will get captured in the trace
# as compute delay. For replay, ROB, LQ and SQ sizes are
# modelled in the Trace CPU.
cpu.numROBEntries = 512;
cpu.LQEntries = 128;
cpu.SQEntries = 128;
else:
fatal("%s does not support data dependency tracing. Use a CPU model of"
" type or inherited from DerivO3CPU.", cpu_cls)
# Add all CPUs in the object hierarchy.
for name, cls in inspect.getmembers(m5.objects, is_cpu_class):
_cpu_classes[name] = cls
from m5.defines import buildEnv
from importlib import import_module
for package in [ "generic", buildEnv['TARGET_ISA']]:
try:
package = import_module(".cores." + package, package=__package__)
except ImportError:
# No timing models for this ISA
continue
for mod_name, module in inspect.getmembers(package, inspect.ismodule):
for name, cls in inspect.getmembers(module, is_cpu_class):
_cpu_classes[name] = cls