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#include "mem/qos/policy_pf.hh"
41
42#include "mem/request.hh"
43
44namespace QoS {
45
46PropFairPolicy::PropFairPolicy(const Params* p)
47  : Policy(p), weight(p->weight)
48{
49    fatal_if(weight < 0 || weight > 1,
50        "weight must be a value between 0 and 1");
51}
52
53PropFairPolicy::~PropFairPolicy()
54{}
55
56template <typename Master>
57void
58PropFairPolicy::initMaster(const Master master, const double score)
59{
60    MasterID m_id = memCtrl->system()->lookupMasterId(master);
61
62    assert(m_id != Request::invldMasterId);
63
64    // Setting the Initial score for the selected master.
65    history.push_back(std::make_pair(m_id, score));
66
67    fatal_if(history.size() > memCtrl->numPriorities(),
68        "Policy's maximum number of masters is currently dictated "
69        "by the maximum number of priorities\n");
70}
71
72void
73PropFairPolicy::initMasterName(const std::string master, const double score)
74{
75    initMaster(master, score);
76}
77
78void
79PropFairPolicy::initMasterObj(const SimObject* master, const double score)
80{
81    initMaster(master, score);
82}
83
84double
85PropFairPolicy::updateScore(
86    const double old_score, const uint64_t served_bytes) const
87{
88    return ((1.0 - weight) * old_score) + (weight * served_bytes);
89}
90
91uint8_t
92PropFairPolicy::schedule(const MasterID pkt_mid, const uint64_t pkt_size)
93{
94    auto sort_pred =
95    [] (const MasterHistory& lhs, const MasterHistory& rhs)
96    { return lhs.second > rhs.second; };
97
98    // Sorting in reverse in base of personal history:
99    // First elements have higher history/score -> lower priority.
100    // The qos priority is the position in the sorted vector.
101    std::sort(history.begin(), history.end(), sort_pred);
102
103    const double served_bytes = static_cast<double>(pkt_size);
104
105    uint8_t pkt_priority = 0;
106    for (auto m_hist = history.begin(); m_hist != history.end(); m_hist++) {
107
108        MasterID curr_mid = m_hist->first;
109        double& curr_score = m_hist->second;
110
111        if (curr_mid == pkt_mid) {
112            // The qos priority is the position in the sorted vector.
113            pkt_priority = std::distance(history.begin(), m_hist);
114
115            curr_score = updateScore(curr_score, served_bytes);
116        } else {
117            curr_score = updateScore(curr_score, 0);
118        }
119    }
120
121    return pkt_priority;
122}
123
124} // namespace QoS
125
126QoS::PropFairPolicy *
127QoSPropFairPolicyParams::create()
128{
129    return new QoS::PropFairPolicy(this);
130}
131