gem5/configs/common/O3_ARM_v7a.py
Andreas Hansson 554ddc7c07 arch, cpu: Do not forward snoops to table walker
This patch simplifies the overall CPU by changing the TLB caches such
that they do not forward snoops to the table walker port(s). Note that
only ARM and X86 are affected.

There is no reason for the ports to snoop as they do not actually take
any action, and from a performance point of view we are better of not
snooping more than we have to.

Should it at a later point be required to snoop for a particular TLB
design it is easy enough to add it back.
2015-05-05 03:22:27 -04:00

191 lines
6.1 KiB
Python

# Copyright (c) 2012 The Regents of The University of Michigan
# All rights reserved.
#
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# neither the name of the copyright holders nor the names of its
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# Authors: Ron Dreslinski
from m5.objects import *
# Simple ALU Instructions have a latency of 1
class O3_ARM_v7a_Simple_Int(FUDesc):
opList = [ OpDesc(opClass='IntAlu', opLat=1) ]
count = 2
# Complex ALU instructions have a variable latencies
class O3_ARM_v7a_Complex_Int(FUDesc):
opList = [ OpDesc(opClass='IntMult', opLat=3, pipelined=True),
OpDesc(opClass='IntDiv', opLat=12, pipelined=False),
OpDesc(opClass='IprAccess', opLat=3, pipelined=True) ]
count = 1
# Floating point and SIMD instructions
class O3_ARM_v7a_FP(FUDesc):
opList = [ OpDesc(opClass='SimdAdd', opLat=4),
OpDesc(opClass='SimdAddAcc', opLat=4),
OpDesc(opClass='SimdAlu', opLat=4),
OpDesc(opClass='SimdCmp', opLat=4),
OpDesc(opClass='SimdCvt', opLat=3),
OpDesc(opClass='SimdMisc', opLat=3),
OpDesc(opClass='SimdMult',opLat=5),
OpDesc(opClass='SimdMultAcc',opLat=5),
OpDesc(opClass='SimdShift',opLat=3),
OpDesc(opClass='SimdShiftAcc', opLat=3),
OpDesc(opClass='SimdSqrt', opLat=9),
OpDesc(opClass='SimdFloatAdd',opLat=5),
OpDesc(opClass='SimdFloatAlu',opLat=5),
OpDesc(opClass='SimdFloatCmp', opLat=3),
OpDesc(opClass='SimdFloatCvt', opLat=3),
OpDesc(opClass='SimdFloatDiv', opLat=3),
OpDesc(opClass='SimdFloatMisc', opLat=3),
OpDesc(opClass='SimdFloatMult', opLat=3),
OpDesc(opClass='SimdFloatMultAcc',opLat=1),
OpDesc(opClass='SimdFloatSqrt', opLat=9),
OpDesc(opClass='FloatAdd', opLat=5),
OpDesc(opClass='FloatCmp', opLat=5),
OpDesc(opClass='FloatCvt', opLat=5),
OpDesc(opClass='FloatDiv', opLat=9, pipelined=False),
OpDesc(opClass='FloatSqrt', opLat=33, pipelined=False),
OpDesc(opClass='FloatMult', opLat=4) ]
count = 2
# Load/Store Units
class O3_ARM_v7a_Load(FUDesc):
opList = [ OpDesc(opClass='MemRead',opLat=2) ]
count = 1
class O3_ARM_v7a_Store(FUDesc):
opList = [OpDesc(opClass='MemWrite',opLat=2) ]
count = 1
# Functional Units for this CPU
class O3_ARM_v7a_FUP(FUPool):
FUList = [O3_ARM_v7a_Simple_Int(), O3_ARM_v7a_Complex_Int(),
O3_ARM_v7a_Load(), O3_ARM_v7a_Store(), O3_ARM_v7a_FP()]
# Bi-Mode Branch Predictor
class O3_ARM_v7a_BP(BiModeBP):
globalPredictorSize = 8192
globalCtrBits = 2
choicePredictorSize = 8192
choiceCtrBits = 2
BTBEntries = 2048
BTBTagSize = 18
RASSize = 16
instShiftAmt = 2
class O3_ARM_v7a_3(DerivO3CPU):
LQEntries = 16
SQEntries = 16
LSQDepCheckShift = 0
LFSTSize = 1024
SSITSize = 1024
decodeToFetchDelay = 1
renameToFetchDelay = 1
iewToFetchDelay = 1
commitToFetchDelay = 1
renameToDecodeDelay = 1
iewToDecodeDelay = 1
commitToDecodeDelay = 1
iewToRenameDelay = 1
commitToRenameDelay = 1
commitToIEWDelay = 1
fetchWidth = 3
fetchBufferSize = 16
fetchToDecodeDelay = 3
decodeWidth = 3
decodeToRenameDelay = 2
renameWidth = 3
renameToIEWDelay = 1
issueToExecuteDelay = 1
dispatchWidth = 6
issueWidth = 8
wbWidth = 8
fuPool = O3_ARM_v7a_FUP()
iewToCommitDelay = 1
renameToROBDelay = 1
commitWidth = 8
squashWidth = 8
trapLatency = 13
backComSize = 5
forwardComSize = 5
numPhysIntRegs = 128
numPhysFloatRegs = 192
numIQEntries = 32
numROBEntries = 40
switched_out = False
branchPred = O3_ARM_v7a_BP()
# Instruction Cache
class O3_ARM_v7a_ICache(BaseCache):
hit_latency = 1
response_latency = 1
mshrs = 2
tgts_per_mshr = 8
size = '32kB'
assoc = 2
is_top_level = True
forward_snoops = False
# Data Cache
class O3_ARM_v7a_DCache(BaseCache):
hit_latency = 2
response_latency = 2
mshrs = 6
tgts_per_mshr = 8
size = '32kB'
assoc = 2
write_buffers = 16
is_top_level = True
# TLB Cache
# Use a cache as a L2 TLB
class O3_ARM_v7aWalkCache(BaseCache):
hit_latency = 4
response_latency = 4
mshrs = 6
tgts_per_mshr = 8
size = '1kB'
assoc = 8
write_buffers = 16
is_top_level = True
forward_snoops = False
# L2 Cache
class O3_ARM_v7aL2(BaseCache):
hit_latency = 12
response_latency = 12
mshrs = 16
tgts_per_mshr = 8
size = '1MB'
assoc = 16
write_buffers = 8
prefetch_on_access = True
# Simple stride prefetcher
prefetcher = StridePrefetcher(degree=8, latency = 1)
tags = RandomRepl()