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
7 * property including but not limited to intellectual property relating
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
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
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
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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
46namespace 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 */
59class 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__
118