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/*
* Copyright (c) 2012-2013, 2016-2018 ARM Limited
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*
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*
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* this software without specific prior written permission.
*
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#ifndef __CPU_TRAFFIC_GEN_TRAFFIC_GEN_HH__
#define __CPU_TRAFFIC_GEN_TRAFFIC_GEN_HH__
#include <unordered_map>
#include "cpu/testers/traffic_gen/base.hh"
namespace gem5
{
struct TrafficGenParams;
/**
* The traffic generator is a module that generates stimuli for
* the memory system, based on a collection of simple behaviours that
* are either probabilistic or based on traces. It can be used stand
* alone for creating test cases for interconnect and memory
* controllers, or function as a black-box replacement for system
* components that are not yet modelled in detail, e.g. a video engine
* or baseband subsystem in an SoC.
*
* The traffic generator has a single request port that is used to send
* requests, independent of the specific behaviour. The behaviour of
* the traffic generator is specified in a configuration file, and this
* file describes a state transition graph where each state is a
* specific generator behaviour. Examples include idling, generating
* linear address sequences, random sequences and replay of captured
* traces. By describing these behaviours as states, it is straight
* forward to create very complex behaviours, simply by arranging them
* in graphs. The graph transitions can also be annotated with
* probabilities, effectively making it a Markov Chain.
*/
class TrafficGen : public BaseTrafficGen
{
private: // Params
/**
* The config file to parse.
*/
const std::string configFile;
private:
/**
* Resolve a file path in the configuration file.
*
* This method resolves a relative path to a file that has been
* referenced in the configuration file. It first tries to resolve
* the file relative to the configuration file's path. If that
* fails, it falls back to constructing a path relative to the
* current working directory.
*
* Absolute paths are returned unmodified.
*
* @param name Path to resolve
*/
std::string resolveFile(const std::string &name);
/**
* Parse the config file and build the state map and
* transition matrix.
*/
void parseConfig();
/**
* Use the transition matrix to find the next state index.
*/
size_t nextState();
/** Struct to represent a probabilistic transition during parsing. */
struct Transition
{
uint32_t from;
uint32_t to;
double p;
};
/** State transition matrix */
std::vector<std::vector<double> > transitionMatrix;
/** Index of the current state */
uint32_t currState;
/** Map of generator states */
std::unordered_map<uint32_t, std::shared_ptr<BaseGen>> states;
protected: // BaseTrafficGen
std::shared_ptr<BaseGen> nextGenerator() override;
public:
TrafficGen(const TrafficGenParams &p);
~TrafficGen() {}
void init() override;
void initState() override;
void serialize(CheckpointOut &cp) const override;
void unserialize(CheckpointIn &cp) override;
};
} // namespace gem5
#endif //__CPU_TRAFFIC_GEN_TRAFFIC_GEN_HH__