src/mem/qos/policy_pf.hh

   1 /*
   2  * Copyright (c) 2018 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
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   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
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  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Author: Giacomo Travaglini
  38  */
  39
  40 #ifndef __MEM_QOS_POLICY_PF_HH__
  41 #define __MEM_QOS_POLICY_PF_HH__
  42
  43 #include "mem/qos/policy.hh"
  44 #include "params/QoSPropFairPolicy.hh"
  45
  46 namespace QoS {
  47
  48 /**
  49  * Proportional Fair QoS Policy
  50  * Providing a configurable fair scheduling policy based on
  51  * utilization; utilization is directly proportional to a
  52  * score which is inversely proportional to the QoS priority
  53  * Users can tune the policy by adjusting the weight parameter
  54  * (weight of the formula)
  55  *
  56  * This is the formula used by the policy
  57  * ((1.0 - weight) * old_score) + (weight * served_bytes);
  58  */
  59 class PropFairPolicy : public Policy
  60 {
  61     using Params = QoSPropFairPolicyParams;
  62     const Params *params() const
  63     { return static_cast<const Params *>(_params); }
  64
  65   public:
  66     PropFairPolicy(const Params*);
  67     virtual ~PropFairPolicy();
  68
  69     /**
  70      * Initialize the master's score by providing
  71      * the master's name and initial score value.
  72      * The master's name has to match a name in the system.
  73      *
  74      * @param master master's name to lookup.
  75      * @param score initial score value for the master
  76      */
  77     void initMasterName(const std::string master, const double score);
  78
  79     /**
  80      * Initialize the master's score by providing
  81      * the master's SimObject pointer and initial score value.
  82      * The master's pointer has to match a master in the system.
  83      *
  84      * @param master master's SimObject pointer to lookup.
  85      * @param score initial score value for the master
  86      */
  87     void initMasterObj(const SimObject* master, const double score);
  88
  89     /**
  90      * Schedules a packet based on proportional fair configuration
  91      *
  92      * @param m_id master id to schedule
  93      * @param pkt_size size of the packet
  94      * @return QoS priority value
  95      */
  96     virtual uint8_t
  97     schedule(const MasterID m_id, const uint64_t pkt_size) override;
  98
  99   protected:
 100     template <typename Master>
 101     void initMaster(const Master master, const double score);
 102
 103     inline double
 104     updateScore(const double old_score, const uint64_t served_bytes) const;
 105
 106   protected:
 107     /** PF Policy weight */
 108     const double weight;
 109
 110     /** history is keeping track of every master's score */
 111     using MasterHistory = std::pair<MasterID, double>;
 112     std::vector<MasterHistory> history;
 113 };
 114
 115 } // namespace QoS
 116
 117 #endif // __MEM_QOS_POLICY_PF_HH__