src/cpu/pred/multiperspective_perceptron_tage.hh - public/gem5 - Git at Google

 /*
  * Copyright 2019 Texas A&M University
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright notice,
  *    this list of conditions and the following disclaimer.
  *
  * 2. 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.
  *
  * 3. Neither the name of the copyright holder 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
  *  HOLDER 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.
  *
  *  Author: Daniel A. Jiménez
  *  Adapted to gem5 by: Javier Bueno Hedo
  *
  */

 /*
  * Multiperspective Perceptron Predictor with TAGE (by Daniel A. Jiménez)
  */

 #ifndef __CPU_PRED_MULTIPERSPECTIVE_PERCEPTRON_TAGE_HH__
 #define __CPU_PRED_MULTIPERSPECTIVE_PERCEPTRON_TAGE_HH__

 #include "cpu/pred/loop_predictor.hh"
 #include "cpu/pred/multiperspective_perceptron.hh"
 #include "cpu/pred/statistical_corrector.hh"
 #include "cpu/pred/tage_base.hh"
 #include "params/MPP_LoopPredictor.hh"
 #include "params/MPP_StatisticalCorrector.hh"
 #include "params/MPP_TAGE.hh"
 #include "params/MultiperspectivePerceptronTAGE.hh"

 namespace gem5
 {

 namespace branch_prediction
 {

 class MPP_TAGE : public TAGEBase
 {
     std::vector<unsigned int> tunedHistoryLengths;
   public:
     struct BranchInfo : public TAGEBase::BranchInfo
     {
         BranchInfo(TAGEBase &tage) : TAGEBase::BranchInfo(tage)
         {}
         virtual ~BranchInfo()
         {}
     };

     MPP_TAGE(const MPP_TAGEParams &p) : TAGEBase(p),
         tunedHistoryLengths(p.tunedHistoryLengths)
     {}

     void calculateParameters() override;
     void handleTAGEUpdate(Addr branch_pc, bool taken, TAGEBase::BranchInfo* bi)
         override;
     void handleAllocAndUReset(bool alloc, bool taken, TAGEBase::BranchInfo* bi,
                               int nrand) override;
     void handleUReset() override;
     void resetUctr(uint8_t &u) override;
     int bindex(Addr pc_in) const override;
     bool isHighConfidence(TAGEBase::BranchInfo *bi) const override;

     unsigned getUseAltIdx(TAGEBase::BranchInfo* bi, Addr branch_pc) override;
     void adjustAlloc(bool & alloc, bool taken, bool pred_taken) override;
     void updateHistories(ThreadID tid, Addr branch_pc, bool taken,
                          TAGEBase::BranchInfo* b, bool speculative,
                          const StaticInstPtr &inst, Addr target) override;

     void updatePathAndGlobalHistory(ThreadHistory& tHist, int brtype,
                                     bool taken, Addr branch_pc, Addr target);
 };

 class MPP_LoopPredictor : public LoopPredictor
 {
   public:
     MPP_LoopPredictor(const MPP_LoopPredictorParams &p) : LoopPredictor(p)
     {}

     bool calcConf(int index) const override;
     bool optionalAgeInc() const override;
 };

 class MPP_StatisticalCorrector : public StatisticalCorrector
 {
   protected:
     int8_t thirdH;
     // global branch history variation GEHL
     const unsigned pnb;
     const unsigned logPnb;
     std::vector<int> pm;
     std::vector<int8_t> * pgehl;
     std::vector<int8_t> wp;

     // global branch history GEHL
     const unsigned gnb;
     const unsigned logGnb;
     std::vector<int> gm;
     std::vector<int8_t> * ggehl;
     std::vector<int8_t> wg;

     struct MPP_SCThreadHistory : public StatisticalCorrector::SCThreadHistory
     {
         MPP_SCThreadHistory() : globalHist(0), historyStack(16, 0),
             historyStackPointer(0) {}
         int64_t globalHist; // global history
         std::vector<int64_t> historyStack;
         unsigned int historyStackPointer;

         int64_t getHistoryStackEntry() const
         {
             return historyStack[historyStackPointer];
         }

         void updateHistoryStack(Addr target, bool taken, bool is_call,
                                 bool is_return)
         {
             unsigned int truncated_target = target;
             historyStack[historyStackPointer] =
                 (historyStack[historyStackPointer] << 1) ^ (truncated_target ^
                 (truncated_target >> 5) ^ taken);
             if (is_return) {
                 historyStackPointer = (historyStackPointer - 1) %
                     historyStack.size();
             }
             if (is_call) {
                 int index = (historyStackPointer + 1) % historyStack.size();
                 historyStack[index] = historyStack[historyStackPointer];
                 historyStackPointer = index;
             }
         }
         unsigned int getPointer() const { return historyStackPointer; }
     };

   public:
     struct BranchInfo : public StatisticalCorrector::BranchInfo
     {
         virtual ~BranchInfo()
         {}
     };
     MPP_StatisticalCorrector(const MPP_StatisticalCorrectorParams &p);

     void initBias() override;
     unsigned getIndBias(Addr branch_pc, StatisticalCorrector::BranchInfo* bi,
                         bool bias) const override;
     unsigned getIndBiasSK(Addr branch_pc, StatisticalCorrector::BranchInfo* bi)
             const override;
     unsigned getIndBiasBank(Addr branch_pc,
                             StatisticalCorrector::BranchInfo* bi, int hitBank,
                             int altBank) const override;
     unsigned getIndUpd(Addr branch_pc) const override;
     int gIndexLogsSubstr(int nbr, int i) override;

     bool scPredict(ThreadID tid, Addr branch_pc, bool cond_branch,
                    StatisticalCorrector::BranchInfo* bi, bool prev_pred_taken,
                    bool bias_bit, bool use_conf_ctr, int8_t conf_ctr,
                    unsigned conf_bits, int hitBank, int altBank, int64_t phist,
                    int init_lsum) override;

     void condBranchUpdate(ThreadID tid, Addr branch_pc, bool taken,
                           StatisticalCorrector::BranchInfo *bi,
                           Addr corrTarget, bool b, int hitBank, int altBank,
                           int64_t phist) override;

     virtual void getBiasLSUM(Addr branch_pc,
             StatisticalCorrector::BranchInfo *bi, int &lsum) const = 0;

     void gUpdate(
         Addr branch_pc, bool taken, int64_t hist, std::vector<int> & length,
         std::vector<int8_t> * tab, int nbr, int logs,
         std::vector<int8_t> &w, StatisticalCorrector::BranchInfo* bi) override;
 };

 class MultiperspectivePerceptronTAGE : public MultiperspectivePerceptron
 {
     TAGEBase *tage;
     LoopPredictor *loopPredictor;
     StatisticalCorrector *statisticalCorrector;

     /**
      * Branch information data type
      */
     struct MPPTAGEBranchInfo : public MPPBranchInfo
     {
         TAGEBase::BranchInfo *tageBranchInfo;
         LoopPredictor::BranchInfo *lpBranchInfo;
         StatisticalCorrector::BranchInfo *scBranchInfo;
         bool predictedTaken;
         MPPTAGEBranchInfo(Addr pc, int pcshift, bool cond, TAGEBase &tage,
                           LoopPredictor &loopPredictor,
                           StatisticalCorrector &statisticalCorrector)
           : MPPBranchInfo(pc, pcshift, cond),
             tageBranchInfo(tage.makeBranchInfo()),
             lpBranchInfo(loopPredictor.makeBranchInfo()),
             scBranchInfo(statisticalCorrector.makeBranchInfo()),
             predictedTaken(false)
         {}
         virtual ~MPPTAGEBranchInfo()
         {
             delete tageBranchInfo;
             delete lpBranchInfo;
             delete scBranchInfo;
         }
     };

     unsigned int getIndex(ThreadID tid, MPPTAGEBranchInfo &bi,
                           const HistorySpec &spec, int index) const;
     int computePartialSum(ThreadID tid, MPPTAGEBranchInfo &bi) const;
     void updatePartial(ThreadID tid, MPPTAGEBranchInfo &bi, bool taken);
     void updateHistories(ThreadID tid, MPPTAGEBranchInfo &bi, bool taken);

   public:
     MultiperspectivePerceptronTAGE(
         const MultiperspectivePerceptronTAGEParams &p);

     void init() override;

     bool lookup(ThreadID tid, Addr instPC, void * &bp_history) override;

     void update(ThreadID tid, Addr instPC, bool taken,
             void *bp_history, bool squashed,
             const StaticInstPtr & inst,
             Addr corrTarget) override;
     void uncondBranch(ThreadID tid, Addr pc, void * &bp_history) override;
     void squash(ThreadID tid, void *bp_history) override;

 };

 } // namespace branch_prediction
 } // namespace gem5

 #endif//__CPU_PRED_MULTIPERSPECTIVE_PERCEPTRON_TAGE_HH__
	/*
	* Copyright 2019 Texas A&M University
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	*
	* 2. 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.
	*
	* 3. Neither the name of the copyright holder 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
	* HOLDER 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.
	*
	* Author: Daniel A. Jiménez
	* Adapted to gem5 by: Javier Bueno Hedo
	*
	*/

	/*
	* Multiperspective Perceptron Predictor with TAGE (by Daniel A. Jiménez)
	*/

	#ifndef __CPU_PRED_MULTIPERSPECTIVE_PERCEPTRON_TAGE_HH__
	#define __CPU_PRED_MULTIPERSPECTIVE_PERCEPTRON_TAGE_HH__

	#include "cpu/pred/loop_predictor.hh"
	#include "cpu/pred/multiperspective_perceptron.hh"
	#include "cpu/pred/statistical_corrector.hh"
	#include "cpu/pred/tage_base.hh"
	#include "params/MPP_LoopPredictor.hh"
	#include "params/MPP_StatisticalCorrector.hh"
	#include "params/MPP_TAGE.hh"
	#include "params/MultiperspectivePerceptronTAGE.hh"

	namespace gem5
	{

	namespace branch_prediction
	{

	class MPP_TAGE : public TAGEBase
	{
	std::vector<unsigned int> tunedHistoryLengths;
	public:
	struct BranchInfo : public TAGEBase::BranchInfo
	{
	BranchInfo(TAGEBase &tage) : TAGEBase::BranchInfo(tage)
	{}
	virtual ~BranchInfo()
	{}
	};

	MPP_TAGE(const MPP_TAGEParams &p) : TAGEBase(p),
	tunedHistoryLengths(p.tunedHistoryLengths)
	{}

	void calculateParameters() override;
	void handleTAGEUpdate(Addr branch_pc, bool taken, TAGEBase::BranchInfo* bi)
	override;
	void handleAllocAndUReset(bool alloc, bool taken, TAGEBase::BranchInfo* bi,
	int nrand) override;
	void handleUReset() override;
	void resetUctr(uint8_t &u) override;
	int bindex(Addr pc_in) const override;
	bool isHighConfidence(TAGEBase::BranchInfo *bi) const override;

	unsigned getUseAltIdx(TAGEBase::BranchInfo* bi, Addr branch_pc) override;
	void adjustAlloc(bool & alloc, bool taken, bool pred_taken) override;
	void updateHistories(ThreadID tid, Addr branch_pc, bool taken,
	TAGEBase::BranchInfo* b, bool speculative,
	const StaticInstPtr &inst, Addr target) override;

	void updatePathAndGlobalHistory(ThreadHistory& tHist, int brtype,
	bool taken, Addr branch_pc, Addr target);
	};

	class MPP_LoopPredictor : public LoopPredictor
	{
	public:
	MPP_LoopPredictor(const MPP_LoopPredictorParams &p) : LoopPredictor(p)
	{}

	bool calcConf(int index) const override;
	bool optionalAgeInc() const override;
	};

	class MPP_StatisticalCorrector : public StatisticalCorrector
	{
	protected:
	int8_t thirdH;
	// global branch history variation GEHL
	const unsigned pnb;
	const unsigned logPnb;
	std::vector<int> pm;
	std::vector<int8_t> * pgehl;
	std::vector<int8_t> wp;

	// global branch history GEHL
	const unsigned gnb;
	const unsigned logGnb;
	std::vector<int> gm;
	std::vector<int8_t> * ggehl;
	std::vector<int8_t> wg;

	struct MPP_SCThreadHistory : public StatisticalCorrector::SCThreadHistory
	{
	MPP_SCThreadHistory() : globalHist(0), historyStack(16, 0),
	historyStackPointer(0) {}
	int64_t globalHist; // global history
	std::vector<int64_t> historyStack;
	unsigned int historyStackPointer;

	int64_t getHistoryStackEntry() const
	{
	return historyStack[historyStackPointer];
	}

	void updateHistoryStack(Addr target, bool taken, bool is_call,
	bool is_return)
	{
	unsigned int truncated_target = target;
	historyStack[historyStackPointer] =
	(historyStack[historyStackPointer] << 1) ^ (truncated_target ^
	(truncated_target >> 5) ^ taken);
	if (is_return) {
	historyStackPointer = (historyStackPointer - 1) %
	historyStack.size();
	}
	if (is_call) {
	int index = (historyStackPointer + 1) % historyStack.size();
	historyStack[index] = historyStack[historyStackPointer];
	historyStackPointer = index;
	}
	}
	unsigned int getPointer() const { return historyStackPointer; }
	};

	public:
	struct BranchInfo : public StatisticalCorrector::BranchInfo
	{
	virtual ~BranchInfo()
	{}
	};
	MPP_StatisticalCorrector(const MPP_StatisticalCorrectorParams &p);

	void initBias() override;
	unsigned getIndBias(Addr branch_pc, StatisticalCorrector::BranchInfo* bi,
	bool bias) const override;
	unsigned getIndBiasSK(Addr branch_pc, StatisticalCorrector::BranchInfo* bi)
	const override;
	unsigned getIndBiasBank(Addr branch_pc,
	StatisticalCorrector::BranchInfo* bi, int hitBank,
	int altBank) const override;
	unsigned getIndUpd(Addr branch_pc) const override;
	int gIndexLogsSubstr(int nbr, int i) override;

	bool scPredict(ThreadID tid, Addr branch_pc, bool cond_branch,
	StatisticalCorrector::BranchInfo* bi, bool prev_pred_taken,
	bool bias_bit, bool use_conf_ctr, int8_t conf_ctr,
	unsigned conf_bits, int hitBank, int altBank, int64_t phist,
	int init_lsum) override;

	void condBranchUpdate(ThreadID tid, Addr branch_pc, bool taken,
	StatisticalCorrector::BranchInfo *bi,
	Addr corrTarget, bool b, int hitBank, int altBank,
	int64_t phist) override;

	virtual void getBiasLSUM(Addr branch_pc,
	StatisticalCorrector::BranchInfo *bi, int &lsum) const = 0;

	void gUpdate(
	Addr branch_pc, bool taken, int64_t hist, std::vector<int> & length,
	std::vector<int8_t> * tab, int nbr, int logs,
	std::vector<int8_t> &w, StatisticalCorrector::BranchInfo* bi) override;
	};

	class MultiperspectivePerceptronTAGE : public MultiperspectivePerceptron
	{
	TAGEBase *tage;
	LoopPredictor *loopPredictor;
	StatisticalCorrector *statisticalCorrector;

	/**
	* Branch information data type
	*/
	struct MPPTAGEBranchInfo : public MPPBranchInfo
	{
	TAGEBase::BranchInfo *tageBranchInfo;
	LoopPredictor::BranchInfo *lpBranchInfo;
	StatisticalCorrector::BranchInfo *scBranchInfo;
	bool predictedTaken;
	MPPTAGEBranchInfo(Addr pc, int pcshift, bool cond, TAGEBase &tage,
	LoopPredictor &loopPredictor,
	StatisticalCorrector &statisticalCorrector)
	: MPPBranchInfo(pc, pcshift, cond),
	tageBranchInfo(tage.makeBranchInfo()),
	lpBranchInfo(loopPredictor.makeBranchInfo()),
	scBranchInfo(statisticalCorrector.makeBranchInfo()),
	predictedTaken(false)
	{}
	virtual ~MPPTAGEBranchInfo()
	{
	delete tageBranchInfo;
	delete lpBranchInfo;
	delete scBranchInfo;
	}
	};

	unsigned int getIndex(ThreadID tid, MPPTAGEBranchInfo &bi,
	const HistorySpec &spec, int index) const;
	int computePartialSum(ThreadID tid, MPPTAGEBranchInfo &bi) const;
	void updatePartial(ThreadID tid, MPPTAGEBranchInfo &bi, bool taken);
	void updateHistories(ThreadID tid, MPPTAGEBranchInfo &bi, bool taken);

	public:
	MultiperspectivePerceptronTAGE(
	const MultiperspectivePerceptronTAGEParams &p);

	void init() override;

	bool lookup(ThreadID tid, Addr instPC, void * &bp_history) override;

	void update(ThreadID tid, Addr instPC, bool taken,
	void *bp_history, bool squashed,
	const StaticInstPtr & inst,
	Addr corrTarget) override;
	void uncondBranch(ThreadID tid, Addr pc, void * &bp_history) override;
	void squash(ThreadID tid, void *bp_history) override;

	};

	} // namespace branch_prediction
	} // namespace gem5

	#endif//__CPU_PRED_MULTIPERSPECTIVE_PERCEPTRON_TAGE_HH__