Split microtage perf

src/cpu/pred/BranchPredictor.py

@@ -1063,16 +1063,32 @@ class BTBTAGE(TimedBaseBTBPredictor):
     numDelay = 2
     usingMbtbBaseEiterTage = Param.Bool(True, "Whether using MBTB basetable either TAGE ")
 
-class MicroTAGE(BTBTAGE):
-    """A smaller TAGE predictor configuration to assist uBTB"""
-    enableSC = Param.Bool(False, "Enable SC or not")    # TODO: BTBTAGE doesn't support SC
-    numPredictors = 1
-    tableSizes = [512]
-    TTagBitSizes = [16]
-    TTagPcShifts = [1]
-
-    histLengths = [16]
-    numDelay = 0
+class MicroTAGE(TimedBaseBTBPredictor):
+    """Micro-sized BTB TAGE predictor used alongside uBTB"""
+    type = 'MicroTAGE'
+    cxx_class = 'gem5::branch_prediction::btb_pred::MicroTAGE'
+    cxx_header = "cpu/pred/btb/microtage.hh"
+
+    needMoreHistories = Param.Bool(True, "MicroTAGE needs more histories")
+    updateOnRead = Param.Bool(False,"Enable update on read, no need to save tage meta in FTQ")
+    # Keep vector parameters consistent with numPredictors to avoid constructor asserts.
+    numPredictors = Param.Unsigned(1, "Number of TAGE predictors")
+    tableSizes = VectorParam.Unsigned([512],"the TAGE T0~Tn length")
+    TTagBitSizes = VectorParam.Unsigned([16] ,"the T0~Tn entry's tag bit size")
+    TTagPcShifts = VectorParam.Unsigned([1] ,"when the T0~Tn entry's tag generating, PC right shift")
+    blockSize = Param.Unsigned(32,"tage index function uses 32B aligned block address")
+
+    histLengths = VectorParam.Unsigned([18],"the BTB TAGE T0~Tn history length")
+    maxHistLen = Param.Unsigned(970,"The length of history passed from DBP")
+    numTablesToAlloc = Param.Unsigned(1,"The number of table to allocated each time")
+    numWays = Param.Unsigned(2, "Number of ways per set")
+    baseTableSize = Param.Unsigned(256,"Base table size")
+    maxBranchPositions = Param.Unsigned(32,"Maximum branch positions per 64-byte block")
+    useAltOnNaSize = Param.Unsigned(128,"Size of the useAltOnNa table")
+    useAltOnNaWidth = Param.Unsigned(7,"Width of the useAltOnNa table")
+    numBanks = Param.Unsigned(4,"Number of banks for bank conflict simulation")
+    enableBankConflict = Param.Bool(False,"Enable bank conflict simulation")
+    numDelay = Param.Unsigned(0,"Prediction latency in cycles")
 
 class BTBITTAGE(TimedBaseBTBPredictor):
     type = 'BTBITTAGE'
@@ -1162,7 +1178,7 @@ class DecoupledBPUWithBTB(BranchPredictor):
     numStages = Param.Unsigned(4, "Maximum number of stages in the pipeline")
     ubtb = Param.UBTB(UBTB(), "UBTB predictor")
     abtb = Param.AheadBTB(AheadBTB(), "ABTB predictor")
-    microtage = Param.BTBTAGE(MicroTAGE(), "MicroTAGE predictor to assist uBTB")
+    microtage = Param.MicroTAGE(MicroTAGE(), "MicroTAGE predictor to assist uBTB")
     mbtb = Param.MBTB(MBTB(), "MBTB predictor")
     tage = Param.BTBTAGE(BTBTAGE(), "TAGE predictor")
     ittage = Param.BTBITTAGE(BTBITTAGE(), "ITTAGE predictor")

src/cpu/pred/SConscript

@@ -49,7 +49,8 @@ SimObject('BranchPredictor.py', sim_objects=[
     'DecoupledStreamBPU', 'DefaultFTB', 'DecoupledBPUWithFTB',
     'TimedBaseFTBPredictor', 'FTBTAGE', 'FTBRAS', 'FTBuRAS', 'FTBITTAGE',
     'AheadBTB', 'MBTB', 'UBTB', 'DecoupledBPUWithBTB',
-    'TimedBaseBTBPredictor', 'BTBRAS', 'BTBTAGE', 'BTBITTAGE', 'BTBMGSC'], enums=["BpType"])
+    'TimedBaseBTBPredictor', 'BTBRAS', 'BTBTAGE', 'MicroTAGE',
+    'BTBITTAGE', 'BTBMGSC'], enums=["BpType"])
 
 DebugFlag('Indirect')
 Source('bpred_unit.cc')
@@ -101,6 +102,7 @@ Source('btb/mbtb.cc')
 Source('btb/timed_base_pred.cc')
 Source('btb/fetch_target_queue.cc')
 Source('btb/btb_tage.cc')
+Source('btb/microtage.cc')
 Source('btb/btb_ittage.cc')
 Source('btb/btb_mgsc.cc')
 Source('btb/folded_hist.cc')

src/cpu/pred/btb/decoupled_bpred.hh

@@ -15,15 +15,16 @@
 #include "cpu/o3/dyn_inst_ptr.hh"
 #include "cpu/pred/bpred_unit.hh"
 #include "cpu/pred/btb/abtb.hh"
-#include "cpu/pred/btb/mbtb.hh"
 #include "cpu/pred/btb/btb_ittage.hh"
+#include "cpu/pred/btb/btb_mgsc.hh"
 #include "cpu/pred/btb/btb_tage.hh"
 #include "cpu/pred/btb/btb_ubtb.hh"
-#include "cpu/pred/btb/btb_mgsc.hh"
 #include "cpu/pred/btb/fetch_target_queue.hh"
 #include "cpu/pred/btb/jump_ahead_predictor.hh"
 #include "cpu/pred/btb/loop_buffer.hh"
 #include "cpu/pred/btb/loop_predictor.hh"
+#include "cpu/pred/btb/mbtb.hh"
+#include "cpu/pred/btb/microtage.hh"
 #include "cpu/pred/btb/ras.hh"
 #include "cpu/pred/general_arch_db.hh"
 
@@ -103,7 +104,7 @@ class DecoupledBPUWithBTB : public BPredUnit
     UBTB *ubtb{};
     AheadBTB *abtb{};
     MBTB *mbtb{};
-    BTBTAGE *microtage{};
+    MicroTAGE *microtage{};
     BTBTAGE *tage{};
     BTBITTAGE *ittage{};
     BTBMGSC *mgsc{};