hybrid_pred.hh

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· HH 代码 · 共 205 行

/*
 * Copyright (c) 2001, 2002, 2003, 2004, 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 *
 * Authors: Steven E. Raasch
 *          Steven K. Reinhardt
 */

//==========================================================================
//
//  This predictor takes the AND of a "local" and a "global" predictor
//  in order to determine its prediction.
//
//
//
//

#ifndef __HYBRID_PRED_HH__
#define __HYBRID_PRED_HH__

#include <string>

#include "base/sat_counter.hh"
#include "base/statistics.hh"

class HybridPredictor : public GenericPredictor
{
  private:
    std::string pred_name;
    std::string one_name;
    std::string zero_name;
    bool reg_individual_stats;

    SaturatingCounterPred *local;
    SaturatingCounterPred *global;

    unsigned long max_index;

    //
    //  Stats
    //
    Stats::Scalar<> pred_one; //num_one_preds
    Stats::Scalar<> pred_zero; //num_zero_preds
    Stats::Scalar<> correct_pred_one; //num_one_correct
    Stats::Scalar<> correct_pred_zero; //num_zero_correct
    Stats::Scalar<> record_one; //num_one_updates
    Stats::Scalar<> record_zero; //num_zero_updates

    Stats::Formula total_preds;
    Stats::Formula frac_preds_zero;
    Stats::Formula frac_preds_one;
    Stats::Formula total_correct;
    Stats::Formula total_accuracy;
    Stats::Formula zero_accuracy;
    Stats::Formula one_accuracy;
    Stats::Formula zero_coverage;
    Stats::Formula one_coverage;

  public:
    HybridPredictor(const char *_p_name, const char *_z_name,
                    const char *_o_name,
                    unsigned _index_bits, unsigned _counter_bits,
                    unsigned _zero_change, unsigned _one_change,
                    unsigned _thresh,
                    unsigned _global_bits, unsigned _global_thresh,
                    bool _reg_individual_stats = false);

    void clear() {
        global->clear();
        local->clear();
    }

    unsigned peek(unsigned long _index) {
        unsigned l = local->peek(_index);
        unsigned g = global->peek(_index);

        if (l && g)
            return 1;

        return 0;
    }

    unsigned value(unsigned long _index) {
        unsigned l = local->peek(_index);
        unsigned g = global->peek(_index);

        l = l & 0xFFFF;
        g = g & 0xFFFF;

        return  (l << 16) | g;

    }

    unsigned predict(unsigned long _index) {
        unsigned l = local->predict(_index);
        unsigned g = global->predict(_index);

        if (l && g) {
            ++pred_one;
            return 1;
        }

        ++pred_zero;
        return 0;
    }


    //
    //  This version need only be used if local/global statistics
    //  will be maintained
    //
    unsigned predict(unsigned long _index, unsigned &_pdata) {
        unsigned l = local->predict(_index);
        unsigned g = global->predict(_index);

        //
        //  bit 0 => local predictor result
        //  bit 1 => global predictor result
        //
        _pdata = 0;
        if (l)
            _pdata |= 1;
        if (g)
            _pdata |= 2;
        if (l && g) {
            ++pred_one;
            return 1;
        }

        ++pred_zero;
        return 0;
    }

    void record(unsigned long _index, unsigned _val, unsigned _predicted) {

        if (_val) {
            local->record(_index, _val, 0);
            global->record(_index, _val, 0);
            ++record_one;

            if (_val == _predicted) {
                ++correct_pred_one;
            }
        } else {
            local->record(_index, _val, 0);
            global->record(_index, _val, 0);
            ++record_zero;

            if (_val == _predicted)
                ++correct_pred_zero;
        }
    }

    void record(unsigned long _index, unsigned _val, unsigned _predicted,
                unsigned _pdata)
    {

        local->record(_index, _val, (_pdata & 1));
        global->record(_index, _val, ((_pdata & 2) ? 1 : 0));


        if (_val) {
            ++record_one;

            if (_val == _predicted)
                ++correct_pred_one;
        } else {
            ++record_zero;

            if (_val == _predicted)
                ++correct_pred_zero;
        }
    }

    void regStats();
    void regFormulas();
};


#endif  // _HYBRID_PRED_HH__