1/*
2 * Copyright (c) 2012-2013, 2016-2018 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

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39 * Sascha Bischoff
40 */
41
42#ifndef __CPU_TRAFFIC_GEN_TRAFFIC_GEN_HH__
43#define __CPU_TRAFFIC_GEN_TRAFFIC_GEN_HH__
44
45#include <unordered_map>
46
47#include "cpu/testers/traffic_gen/base.hh"
48
49struct TrafficGenParams;
50
51/**
52 * The traffic generator is a master module that generates stimuli for
53 * the memory system, based on a collection of simple behaviours that
54 * are either probabilistic or based on traces. It can be used stand
55 * alone for creating test cases for interconnect and memory
56 * controllers, or function as a black-box replacement for system
57 * components that are not yet modelled in detail, e.g. a video engine
58 * or baseband subsystem in an SoC.
59 *
60 * The traffic generator has a single master port that is used to send
61 * requests, independent of the specific behaviour. The behaviour of
62 * the traffic generator is specified in a configuration file, and this
63 * file describes a state transition graph where each state is a
64 * specific generator behaviour. Examples include idling, generating
65 * linear address sequences, random sequences and replay of captured
66 * traces. By describing these behaviours as states, it is straight
67 * forward to create very complex behaviours, simply by arranging them
68 * in graphs. The graph transitions can also be annotated with
69 * probabilities, effectively making it a Markov Chain.
70 */
71class TrafficGen : public BaseTrafficGen
72{
73 private: // Params
74 /**
75 * The config file to parse.
76 */
77 const std::string configFile;
78
79 private:
80 /**
81 * Resolve a file path in the configuration file.
82 *
83 * This method resolves a relative path to a file that has been
84 * referenced in the configuration file. It first tries to resolve
85 * the file relative to the configuration file's path. If that
86 * fails, it falls back to constructing a path relative to the
87 * current working directory.
88 *
89 * Absolute paths are returned unmodified.
90 *
91 * @param name Path to resolve
92 */
93 std::string resolveFile(const std::string &name);
94
95 /**
96 * Parse the config file and build the state map and
97 * transition matrix.
98 */
99 void parseConfig();
100
101 /**
102 * Use the transition matrix to find the next state index.
103 */
104 size_t nextState();
105
106 /** Struct to represent a probabilistic transition during parsing. */
107 struct Transition {
108 uint32_t from;
109 uint32_t to;
110 double p;
111 };
112
113 /** State transition matrix */
114 std::vector<std::vector<double> > transitionMatrix;
115
116 /** Index of the current state */
117 uint32_t currState;
118
119 /** Map of generator states */
120 std::unordered_map<uint32_t, std::shared_ptr<BaseGen>> states;
121
122 protected: // BaseTrafficGen
123 std::shared_ptr<BaseGen> nextGenerator() override;
124
125 public:
126
127 TrafficGen(const TrafficGenParams* p);
128
129 ~TrafficGen() {}
130
131 void init() override;
132 void initState() override;
133
134 void serialize(CheckpointOut &cp) const override;
135 void unserialize(CheckpointIn &cp) override;
136
137};
138
139#endif //__CPU_TRAFFIC_GEN_TRAFFIC_GEN_HH__