cpu: Fix bi-mode branch predictor thresholds

[gem5.git] / src / cpu / pred / BranchPredictor.py

diff --git a/src/cpu/pred/BranchPredictor.py b/src/cpu/pred/BranchPredictor.py
index 1bdc71d4d1fbfceafa9f0e9b638e638caf0a3088..1b400c2b769b64a95a512845ce1e66b64afa9d69 100644 (file)
--- a/src/cpu/pred/BranchPredictor.py
+++ b/src/cpu/pred/BranchPredictor.py
@@ -1,4 +1,5 @@
 # Copyright (c) 2012 Mark D. Hill and David A. Wood
+# Copyright (c) 2015 The University of Wisconsin
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -24,7 +25,7 @@
 # (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: Nilay Vaish
+# Authors: Nilay Vaish and Dibakar Gope
 
 from m5.SimObject import SimObject
 from m5.params import *
@@ -33,20 +34,71 @@ class BranchPredictor(SimObject):
     type = 'BranchPredictor'
     cxx_class = 'BPredUnit'
     cxx_header = "cpu/pred/bpred_unit.hh"
+    abstract = True
 
     numThreads = Param.Unsigned(1, "Number of threads")
-    predType = Param.String("tournament",
-        "Branch predictor type ('local', 'tournament', 'bi-mode')")
+    BTBEntries = Param.Unsigned(4096, "Number of BTB entries")
+    BTBTagSize = Param.Unsigned(16, "Size of the BTB tags, in bits")
+    RASSize = Param.Unsigned(16, "RAS size")
+    instShiftAmt = Param.Unsigned(2, "Number of bits to shift instructions by")
+
+    useIndirect = Param.Bool(True, "Use indirect branch predictor")
+    indirectHashGHR = Param.Bool(True, "Hash branch predictor GHR")
+    indirectHashTargets = Param.Bool(True, "Hash path history targets")
+    indirectSets = Param.Unsigned(256, "Cache sets for indirect predictor")
+    indirectWays = Param.Unsigned(2, "Ways for indirect predictor")
+    indirectTagSize = Param.Unsigned(16, "Indirect target cache tag bits")
+    indirectPathLength = Param.Unsigned(3,
+        "Previous indirect targets to use for path history")
+
+
+
+class LocalBP(BranchPredictor):
+    type = 'LocalBP'
+    cxx_class = 'LocalBP'
+    cxx_header = "cpu/pred/2bit_local.hh"
+
+    localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
+    localCtrBits = Param.Unsigned(2, "Bits per counter")
+
+
+class TournamentBP(BranchPredictor):
+    type = 'TournamentBP'
+    cxx_class = 'TournamentBP'
+    cxx_header = "cpu/pred/tournament.hh"
+
     localPredictorSize = Param.Unsigned(2048, "Size of local predictor")
     localCtrBits = Param.Unsigned(2, "Bits per counter")
-    localHistoryTableSize = Param.Unsigned(2048, "Size of local history table")
+    localHistoryTableSize = Param.Unsigned(2048, "size of local history table")
     globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
     globalCtrBits = Param.Unsigned(2, "Bits per counter")
     choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
     choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
 
-    BTBEntries = Param.Unsigned(4096, "Number of BTB entries")
-    BTBTagSize = Param.Unsigned(16, "Size of the BTB tags, in bits")
 
-    RASSize = Param.Unsigned(16, "RAS size")
-    instShiftAmt = Param.Unsigned(2, "Number of bits to shift instructions by")
+class BiModeBP(BranchPredictor):
+    type = 'BiModeBP'
+    cxx_class = 'BiModeBP'
+    cxx_header = "cpu/pred/bi_mode.hh"
+
+    globalPredictorSize = Param.Unsigned(8192, "Size of global predictor")
+    globalCtrBits = Param.Unsigned(2, "Bits per counter")
+    choicePredictorSize = Param.Unsigned(8192, "Size of choice predictor")
+    choiceCtrBits = Param.Unsigned(2, "Bits of choice counters")
+
+class LTAGE(BranchPredictor):
+    type = 'LTAGE'
+    cxx_class = 'LTAGE'
+    cxx_header = "cpu/pred/ltage.hh"
+
+    logSizeBiMP = Param.Unsigned(14, "Log size of Bimodal predictor in bits")
+    logSizeTagTables = Param.Unsigned(11, "Log size of tag table in LTAGE")
+    logSizeLoopPred = Param.Unsigned(8, "Log size of the loop predictor")
+    nHistoryTables = Param.Unsigned(12, "Number of history tables")
+    tagTableCounterBits = Param.Unsigned(3, "Number of tag table counter bits")
+    histBufferSize = Param.Unsigned(2097152,
+            "A large number to track all branch histories(2MEntries default)")
+    minHist = Param.Unsigned(4, "Minimum history size of LTAGE")
+    maxHist = Param.Unsigned(640, "Maximum history size of LTAGE")
+    minTagWidth = Param.Unsigned(7, "Minimum tag size in tag tables")
+