1# Copyright (c) 2012 Mark D. Hill and David A. Wood
2# Copyright (c) 2015 The University of Wisconsin
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions are
7# met: redistributions of source code must retain the above copyright
8# notice, this list of conditions and the following disclaimer;
9# redistributions in binary form must reproduce the above copyright
10# notice, this list of conditions and the following disclaimer in the
11# documentation and/or other materials provided with the distribution;
12# neither the name of the copyright holders nor the names of its
13# contributors may be used to endorse or promote products derived from
14# this software without specific prior written permission.
15#
16# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27#
28# Authors: Nilay Vaish and Dibakar Gope
29
30from m5.SimObject import SimObject
31from m5.params import *
32from m5.proxy import *
33
34class BranchPredictor(SimObject):
35 type = 'BranchPredictor'
36 cxx_class = 'BPredUnit'
37 cxx_header = "cpu/pred/bpred_unit.hh"
38 abstract = True
39
40 numThreads = Param.Unsigned(Parent.numThreads, "Number of threads")
41 BTBEntries = Param.Unsigned(4096, "Number of BTB entries")
42 BTBTagSize = Param.Unsigned(16, "Size of the BTB tags, in bits")
43 RASSize = Param.Unsigned(16, "RAS size")
44 instShiftAmt = Param.Unsigned(2, "Number of bits to shift instructions by")
45
46 useIndirect = Param.Bool(True, "Use indirect branch predictor")
47 indirectHashGHR = Param.Bool(True, "Hash branch predictor GHR")
48 indirectHashTargets = Param.Bool(True, "Hash path history targets")
49 indirectSets = Param.Unsigned(256, "Cache sets for indirect predictor")
50 indirectWays = Param.Unsigned(2, "Ways for indirect predictor")
51 indirectTagSize = Param.Unsigned(16, "Indirect target cache tag bits")
52 indirectPathLength = Param.Unsigned(3,
53 "Previous indirect targets to use for path history")
54
55
56
57class LocalBP(BranchPredictor):
58 type = 'LocalBP'
59 cxx_class = 'LocalBP'
60 cxx_header = "cpu/pred/2bit_local.hh"
61
62 localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
63 localCtrBits = Param.Unsigned(2, "Bits per counter")
64
65
66class TournamentBP(BranchPredictor):
67 type = 'TournamentBP'
68 cxx_class = 'TournamentBP'
69 cxx_header = "cpu/pred/tournament.hh"
70
71 localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
72 localCtrBits = Param.Unsigned(2, "Bits per counter")
73 localHistoryTableSize = Param.Unsigned(2048, "size of local history table")
74 globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
75 globalCtrBits = Param.Unsigned(2, "Bits per counter")
76 choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
77 choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
78
79
80class BiModeBP(BranchPredictor):
81 type = 'BiModeBP'
82 cxx_class = 'BiModeBP'
83 cxx_header = "cpu/pred/bi_mode.hh"
84
85 globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
86 globalCtrBits = Param.Unsigned(2, "Bits per counter")
87 choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
88 choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
89
| 1# Copyright (c) 2012 Mark D. Hill and David A. Wood
2# Copyright (c) 2015 The University of Wisconsin
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions are
7# met: redistributions of source code must retain the above copyright
8# notice, this list of conditions and the following disclaimer;
9# redistributions in binary form must reproduce the above copyright
10# notice, this list of conditions and the following disclaimer in the
11# documentation and/or other materials provided with the distribution;
12# neither the name of the copyright holders nor the names of its
13# contributors may be used to endorse or promote products derived from
14# this software without specific prior written permission.
15#
16# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27#
28# Authors: Nilay Vaish and Dibakar Gope
29
30from m5.SimObject import SimObject
31from m5.params import *
32from m5.proxy import *
33
34class BranchPredictor(SimObject):
35 type = 'BranchPredictor'
36 cxx_class = 'BPredUnit'
37 cxx_header = "cpu/pred/bpred_unit.hh"
38 abstract = True
39
40 numThreads = Param.Unsigned(Parent.numThreads, "Number of threads")
41 BTBEntries = Param.Unsigned(4096, "Number of BTB entries")
42 BTBTagSize = Param.Unsigned(16, "Size of the BTB tags, in bits")
43 RASSize = Param.Unsigned(16, "RAS size")
44 instShiftAmt = Param.Unsigned(2, "Number of bits to shift instructions by")
45
46 useIndirect = Param.Bool(True, "Use indirect branch predictor")
47 indirectHashGHR = Param.Bool(True, "Hash branch predictor GHR")
48 indirectHashTargets = Param.Bool(True, "Hash path history targets")
49 indirectSets = Param.Unsigned(256, "Cache sets for indirect predictor")
50 indirectWays = Param.Unsigned(2, "Ways for indirect predictor")
51 indirectTagSize = Param.Unsigned(16, "Indirect target cache tag bits")
52 indirectPathLength = Param.Unsigned(3,
53 "Previous indirect targets to use for path history")
54
55
56
57class LocalBP(BranchPredictor):
58 type = 'LocalBP'
59 cxx_class = 'LocalBP'
60 cxx_header = "cpu/pred/2bit_local.hh"
61
62 localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
63 localCtrBits = Param.Unsigned(2, "Bits per counter")
64
65
66class TournamentBP(BranchPredictor):
67 type = 'TournamentBP'
68 cxx_class = 'TournamentBP'
69 cxx_header = "cpu/pred/tournament.hh"
70
71 localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
72 localCtrBits = Param.Unsigned(2, "Bits per counter")
73 localHistoryTableSize = Param.Unsigned(2048, "size of local history table")
74 globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
75 globalCtrBits = Param.Unsigned(2, "Bits per counter")
76 choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
77 choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
78
79
80class BiModeBP(BranchPredictor):
81 type = 'BiModeBP'
82 cxx_class = 'BiModeBP'
83 cxx_header = "cpu/pred/bi_mode.hh"
84
85 globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
86 globalCtrBits = Param.Unsigned(2, "Bits per counter")
87 choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
88 choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
89
|
90# TAGE branch predictor as described in https://www.jilp.org/vol8/v8paper1.pdf
91# The default sizes below are for the 8C-TAGE configuration (63.5 Kbits)
92class TAGE(BranchPredictor):
93 type = 'TAGE'
94 cxx_class = 'TAGE'
95 cxx_header = "cpu/pred/tage.hh"
| 90class TAGEBase(SimObject):
91 type = 'TAGEBase'
92 cxx_class = 'TAGEBase'
93 cxx_header = "cpu/pred/tage_base.hh"
|
96
| 94
|
| 95 numThreads = Param.Unsigned(Parent.numThreads, "Number of threads")
96 instShiftAmt = Param.Unsigned(Parent.instShiftAmt,
97 "Number of bits to shift instructions by")
98
|
97 nHistoryTables = Param.Unsigned(7, "Number of history tables")
98 minHist = Param.Unsigned(5, "Minimum history size of TAGE")
99 maxHist = Param.Unsigned(130, "Maximum history size of TAGE")
100
101 tagTableTagWidths = VectorParam.Unsigned(
102 [0, 9, 9, 10, 10, 11, 11, 12], "Tag size in TAGE tag tables")
103 logTagTableSizes = VectorParam.Int(
104 [13, 9, 9, 9, 9, 9, 9, 9], "Log2 of TAGE table sizes")
105 logRatioBiModalHystEntries = Param.Unsigned(2,
106 "Log num of prediction entries for a shared hysteresis bit " \
107 "for the Bimodal")
108
109 tagTableCounterBits = Param.Unsigned(3, "Number of tag table counter bits")
110 tagTableUBits = Param.Unsigned(2, "Number of tag table u bits")
111
112 histBufferSize = Param.Unsigned(2097152,
113 "A large number to track all branch histories(2MEntries default)")
114
115 pathHistBits = Param.Unsigned(16, "Path history size")
116 logUResetPeriod = Param.Unsigned(18,
117 "Log period in number of branches to reset TAGE useful counters")
| 99 nHistoryTables = Param.Unsigned(7, "Number of history tables")
100 minHist = Param.Unsigned(5, "Minimum history size of TAGE")
101 maxHist = Param.Unsigned(130, "Maximum history size of TAGE")
102
103 tagTableTagWidths = VectorParam.Unsigned(
104 [0, 9, 9, 10, 10, 11, 11, 12], "Tag size in TAGE tag tables")
105 logTagTableSizes = VectorParam.Int(
106 [13, 9, 9, 9, 9, 9, 9, 9], "Log2 of TAGE table sizes")
107 logRatioBiModalHystEntries = Param.Unsigned(2,
108 "Log num of prediction entries for a shared hysteresis bit " \
109 "for the Bimodal")
110
111 tagTableCounterBits = Param.Unsigned(3, "Number of tag table counter bits")
112 tagTableUBits = Param.Unsigned(2, "Number of tag table u bits")
113
114 histBufferSize = Param.Unsigned(2097152,
115 "A large number to track all branch histories(2MEntries default)")
116
117 pathHistBits = Param.Unsigned(16, "Path history size")
118 logUResetPeriod = Param.Unsigned(18,
119 "Log period in number of branches to reset TAGE useful counters")
|
| 120 numUseAltOnNa = Param.Unsigned(1, "Number of USE_ALT_ON_NA counters")
|
118 useAltOnNaBits = Param.Unsigned(4, "Size of the USE_ALT_ON_NA counter")
119
| 121 useAltOnNaBits = Param.Unsigned(4, "Size of the USE_ALT_ON_NA counter")
122
|
| 123 maxNumAlloc = Param.Unsigned(1,
124 "Max number of TAGE entries allocted on mispredict")
|
120
| 125
|
| 126 # List of enabled TAGE tables. If empty, all are enabled
127 noSkip = VectorParam.Bool([], "Vector of enabled TAGE tables")
128
129 speculativeHistUpdate = Param.Bool(True,
130 "Use speculative update for histories")
131
132# TAGE branch predictor as described in https://www.jilp.org/vol8/v8paper1.pdf
133# The default sizes below are for the 8C-TAGE configuration (63.5 Kbits)
134class TAGE(BranchPredictor):
135 type = 'TAGE'
136 cxx_class = 'TAGE'
137 cxx_header = "cpu/pred/tage.hh"
138 tage = Param.TAGEBase(TAGEBase(), "Tage object")
139
140class LTAGE_TAGE(TAGEBase):
141 nHistoryTables = 12
142 minHist = 4
143 maxHist = 640
144 tagTableTagWidths = [0, 7, 7, 8, 8, 9, 10, 11, 12, 12, 13, 14, 15]
145 logTagTableSizes = [14, 10, 10, 11, 11, 11, 11, 10, 10, 10, 10, 9, 9]
146 logUResetPeriod = 19
147
|
121# LTAGE branch predictor as described in
122# https://www.irisa.fr/caps/people/seznec/L-TAGE.pdf
123# It is basically a TAGE predictor plus a loop predictor
124# The differnt TAGE sizes are updated according to the paper values (256 Kbits)
125class LTAGE(TAGE):
126 type = 'LTAGE'
127 cxx_class = 'LTAGE'
128 cxx_header = "cpu/pred/ltage.hh"
129
| 148# LTAGE branch predictor as described in
149# https://www.irisa.fr/caps/people/seznec/L-TAGE.pdf
150# It is basically a TAGE predictor plus a loop predictor
151# The differnt TAGE sizes are updated according to the paper values (256 Kbits)
152class LTAGE(TAGE):
153 type = 'LTAGE'
154 cxx_class = 'LTAGE'
155 cxx_header = "cpu/pred/ltage.hh"
156
|
130 nHistoryTables = 12
131 minHist = 4
132 maxHist = 640
133 tagTableTagWidths = [0, 7, 7, 8, 8, 9, 10, 11, 12, 12, 13, 14, 15]
134 logTagTableSizes = [14, 10, 10, 11, 11, 11, 11, 10, 10, 10, 10, 9, 9]
135 logUResetPeriod = 19
| 157 tage = LTAGE_TAGE()
|
136
137 logSizeLoopPred = Param.Unsigned(8, "Log size of the loop predictor")
138 withLoopBits = Param.Unsigned(7, "Size of the WITHLOOP counter")
139 loopTableAgeBits = Param.Unsigned(8, "Number of age bits per loop entry")
140 loopTableConfidenceBits = Param.Unsigned(2,
141 "Number of confidence bits per loop entry")
142 loopTableTagBits = Param.Unsigned(14, "Number of tag bits per loop entry")
143 loopTableIterBits = Param.Unsigned(14, "Nuber of iteration bits per loop")
144 logLoopTableAssoc = Param.Unsigned(2, "Log loop predictor associativity")
145
146 # Parameters for enabling modifications to the loop predictor
147 # They have been copied from ISL-TAGE
148 # (https://www.jilp.org/jwac-2/program/03_seznec.tgz)
149 #
150 # All of them should be disabled to match the original LTAGE implementation
151 # (http://hpca23.cse.tamu.edu/taco/camino/cbp2/cbp-src/realistic-seznec.h)
152
153 # Add speculation
154 useSpeculation = Param.Bool(False, "Use speculation")
155
156 # Add hashing for calculating the loop table index
157 useHashing = Param.Bool(False, "Use hashing")
158
159 # Add a direction bit to the loop table entries
160 useDirectionBit = Param.Bool(False, "Use direction info")
161
| 158
159 logSizeLoopPred = Param.Unsigned(8, "Log size of the loop predictor")
160 withLoopBits = Param.Unsigned(7, "Size of the WITHLOOP counter")
161 loopTableAgeBits = Param.Unsigned(8, "Number of age bits per loop entry")
162 loopTableConfidenceBits = Param.Unsigned(2,
163 "Number of confidence bits per loop entry")
164 loopTableTagBits = Param.Unsigned(14, "Number of tag bits per loop entry")
165 loopTableIterBits = Param.Unsigned(14, "Nuber of iteration bits per loop")
166 logLoopTableAssoc = Param.Unsigned(2, "Log loop predictor associativity")
167
168 # Parameters for enabling modifications to the loop predictor
169 # They have been copied from ISL-TAGE
170 # (https://www.jilp.org/jwac-2/program/03_seznec.tgz)
171 #
172 # All of them should be disabled to match the original LTAGE implementation
173 # (http://hpca23.cse.tamu.edu/taco/camino/cbp2/cbp-src/realistic-seznec.h)
174
175 # Add speculation
176 useSpeculation = Param.Bool(False, "Use speculation")
177
178 # Add hashing for calculating the loop table index
179 useHashing = Param.Bool(False, "Use hashing")
180
181 # Add a direction bit to the loop table entries
182 useDirectionBit = Param.Bool(False, "Use direction info")
183
|