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# Copyright (c) 2012-2013, 2015, 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.
#
# Copyright (c) 2005-2007 The Regents of The University of Michigan
# All rights reserved.
#
# 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: Nathan Binkert
# Andreas Hansson
from m5.params import *
from m5.proxy import *
from m5.SimObject import SimObject
from MemObject import MemObject
from Prefetcher import BasePrefetcher
from ReplacementPolicies import *
from Tags import *
# Enum for cache clusivity, currently mostly inclusive or mostly
# exclusive.
class Clusivity(Enum): vals = ['mostly_incl', 'mostly_excl']
class WriteAllocator(SimObject):
type = 'WriteAllocator'
cxx_header = "mem/cache/cache.hh"
# Control the limits for when the cache introduces extra delays to
# allow whole-line write coalescing, and eventually switches to a
# write-no-allocate policy.
coalesce_limit = Param.Unsigned(2, "Consecutive lines written before "
"delaying for coalescing")
no_allocate_limit = Param.Unsigned(12, "Consecutive lines written before"
" skipping allocation")
delay_threshold = Param.Unsigned(8, "Number of delay quanta imposed on an "
"MSHR with write requests to allow for "
"write coalescing")
block_size = Param.Int(Parent.cache_line_size, "block size in bytes")
class BaseCache(MemObject):
type = 'BaseCache'
abstract = True
cxx_header = "mem/cache/base.hh"
size = Param.MemorySize("Capacity")
assoc = Param.Unsigned("Associativity")
tag_latency = Param.Cycles("Tag lookup latency")
data_latency = Param.Cycles("Data access latency")
response_latency = Param.Cycles("Latency for the return path on a miss");
warmup_percentage = Param.Percent(0,
"Percentage of tags to be touched to warm up the cache")
max_miss_count = Param.Counter(0,
"Number of misses to handle before calling exit")
mshrs = Param.Unsigned("Number of MSHRs (max outstanding requests)")
demand_mshr_reserve = Param.Unsigned(1, "MSHRs reserved for demand access")
tgts_per_mshr = Param.Unsigned("Max number of accesses per MSHR")
write_buffers = Param.Unsigned(8, "Number of write buffers")
is_read_only = Param.Bool(False, "Is this cache read only (e.g. inst)")
prefetcher = Param.BasePrefetcher(NULL,"Prefetcher attached to cache")
prefetch_on_access = Param.Bool(False,
"Notify the hardware prefetcher on every access (not just misses)")
tags = Param.BaseTags(BaseSetAssoc(), "Tag store")
replacement_policy = Param.BaseReplacementPolicy(LRURP(),
"Replacement policy")
sequential_access = Param.Bool(False,
"Whether to access tags and data sequentially")
cpu_side = SlavePort("Upstream port closer to the CPU and/or device")
mem_side = MasterPort("Downstream port closer to memory")
addr_ranges = VectorParam.AddrRange([AllMemory],
"Address range for the CPU-side port (to allow striping)")
system = Param.System(Parent.any, "System we belong to")
# Determine if this cache sends out writebacks for clean lines, or
# simply clean evicts. In cases where a downstream cache is mostly
# exclusive with respect to this cache (acting as a victim cache),
# the clean writebacks are essential for performance. In general
# this should be set to True for anything but the last-level
# cache.
writeback_clean = Param.Bool(False, "Writeback clean lines")
# Control whether this cache should be mostly inclusive or mostly
# exclusive with respect to upstream caches. The behaviour on a
# fill is determined accordingly. For a mostly inclusive cache,
# blocks are allocated on all fill operations. Thus, L1 caches
# should be set as mostly inclusive even if they have no upstream
# caches. In the case of a mostly exclusive cache, fills are not
# allocating unless they came directly from a non-caching source,
# e.g. a table walker. Additionally, on a hit from an upstream
# cache a line is dropped for a mostly exclusive cache.
clusivity = Param.Clusivity('mostly_incl',
"Clusivity with upstream cache")
# The write allocator enables optimizations for streaming write
# accesses by first coalescing writes and then avoiding allocation
# in the current cache. Typically, this would be enabled in the
# data cache.
write_allocator = Param.WriteAllocator(NULL, "Write allocator")
class Cache(BaseCache):
type = 'Cache'
cxx_header = 'mem/cache/cache.hh'
class NoncoherentCache(BaseCache):
type = 'NoncoherentCache'
cxx_header = 'mem/cache/noncoherent_cache.hh'
# This is typically a last level cache and any clean
# writebacks would be unnecessary traffic to the main memory.
writeback_clean = False
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