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. More...

#include <traffic_gen.hh>

Inheritance diagram for gem5::TrafficGen:

Classes
struct	Transition
	Struct to represent a probabilistic transition during parsing. More...

Public Member Functions
	TrafficGen (const TrafficGenParams &p)

	~TrafficGen ()

void	init () override
	init() is called after all C++ SimObjects have been created and all ports are connected.

void	initState () override
	initState() is called on each SimObject when not restoring from a checkpoint.

void	serialize (CheckpointOut &cp) const override
	Serialize an object.

void	unserialize (CheckpointIn &cp) override
	Unserialize an object.

Public Member Functions inherited from gem5::BaseTrafficGen
	BaseTrafficGen (const BaseTrafficGenParams &p)

	~BaseTrafficGen ()

Port &	getPort (const std::string &if_name, PortID idx=InvalidPortID) override
	Get a port with a given name and index.

DrainState	drain () override
	Draining is the process of clearing out the states of SimObjects.These are the SimObjects that are partially executed or are partially in flight.

std::shared_ptr< BaseGen >	createIdle (Tick duration)

std::shared_ptr< BaseGen >	createExit (Tick duration)

std::shared_ptr< BaseGen >	createLinear (Tick duration, Addr start_addr, Addr end_addr, Addr blocksize, Tick min_period, Tick max_period, uint8_t read_percent, Addr data_limit)

std::shared_ptr< BaseGen >	createRandom (Tick duration, Addr start_addr, Addr end_addr, Addr blocksize, Tick min_period, Tick max_period, uint8_t read_percent, Addr data_limit)

std::shared_ptr< BaseGen >	createDram (Tick duration, Addr start_addr, Addr end_addr, Addr blocksize, Tick min_period, Tick max_period, uint8_t read_percent, Addr data_limit, unsigned int num_seq_pkts, unsigned int page_size, unsigned int nbr_of_banks, unsigned int nbr_of_banks_util, enums::AddrMap addr_mapping, unsigned int nbr_of_ranks)

std::shared_ptr< BaseGen >	createDramRot (Tick duration, Addr start_addr, Addr end_addr, Addr blocksize, Tick min_period, Tick max_period, uint8_t read_percent, Addr data_limit, unsigned int num_seq_pkts, unsigned int page_size, unsigned int nbr_of_banks, unsigned int nbr_of_banks_util, enums::AddrMap addr_mapping, unsigned int nbr_of_ranks, unsigned int max_seq_count_per_rank)

std::shared_ptr< BaseGen >	createHybrid (Tick duration, Addr start_addr_dram, Addr end_addr_dram, Addr blocksize_dram, Addr start_addr_nvm, Addr end_addr_nvm, Addr blocksize_nvm, Tick min_period, Tick max_period, uint8_t read_percent, Addr data_limit, unsigned int num_seq_pkts_dram, unsigned int page_size_dram, unsigned int nbr_of_banks_dram, unsigned int nbr_of_banks_util_dram, unsigned int num_seq_pkts_nvm, unsigned int buffer_size_nvm, unsigned int nbr_of_banks_nvm, unsigned int nbr_of_banks_util_nvm, enums::AddrMap addr_mapping, unsigned int nbr_of_ranks_dram, unsigned int nbr_of_ranks_nvm, uint8_t nvm_percent)

std::shared_ptr< BaseGen >	createNvm (Tick duration, Addr start_addr, Addr end_addr, Addr blocksize, Tick min_period, Tick max_period, uint8_t read_percent, Addr data_limit, unsigned int num_seq_pkts, unsigned int buffer_size, unsigned int nbr_of_banks, unsigned int nbr_of_banks_util, enums::AddrMap addr_mapping, unsigned int nbr_of_ranks)

std::shared_ptr< BaseGen >	createStrided (Tick duration, Addr start_addr, Addr end_addr, Addr offset, Addr block_size, Addr superblock_size, Addr stride_size, Tick min_period, Tick max_period, uint8_t read_percent, Addr data_limit)

std::shared_ptr< BaseGen >	createTrace (Tick duration, const std::string &trace_file, Addr addr_offset)

Public Member Functions inherited from gem5::ClockedObject
	ClockedObject (const ClockedObjectParams &p)

Public Member Functions inherited from gem5::SimObject
const Params &	params () const

	SimObject (const Params &p)

virtual	~SimObject ()

virtual void	loadState (CheckpointIn &cp)
	loadState() is called on each SimObject when restoring from a checkpoint.

virtual void	regProbePoints ()
	Register probe points for this object.

virtual void	regProbeListeners ()
	Register probe listeners for this object.

ProbeManager *	getProbeManager ()
	Get the probe manager for this object.

virtual void	startup ()
	startup() is the final initialization call before simulation.

DrainState	drain () override
	Provide a default implementation of the drain interface for objects that don't need draining.

virtual void	memWriteback ()
	Write back dirty buffers to memory using functional writes.

virtual void	memInvalidate ()
	Invalidate the contents of memory buffers.

Public Member Functions inherited from gem5::EventManager
EventQueue *	eventQueue () const

void	schedule (Event &event, Tick when)

void	deschedule (Event &event)

void	reschedule (Event &event, Tick when, bool always=false)

void	schedule (Event *event, Tick when)

void	deschedule (Event *event)

void	reschedule (Event *event, Tick when, bool always=false)

void	wakeupEventQueue (Tick when=(Tick) -1)
	This function is not needed by the usual gem5 event loop but may be necessary in derived EventQueues which host gem5 on other schedulers.

void	setCurTick (Tick newVal)

	EventManager (EventManager &em)
	Event manger manages events in the event queue.

	EventManager (EventManager *em)

	EventManager (EventQueue *eq)

Public Member Functions inherited from gem5::Serializable
	Serializable ()

virtual	~Serializable ()

void	serializeSection (CheckpointOut &cp, const char *name) const
	Serialize an object into a new section.

void	serializeSection (CheckpointOut &cp, const std::string &name) const

void	unserializeSection (CheckpointIn &cp, const char *name)
	Unserialize an a child object.

void	unserializeSection (CheckpointIn &cp, const std::string &name)

Public Member Functions inherited from gem5::Drainable
DrainState	drainState () const
	Return the current drain state of an object.

virtual void	notifyFork ()
	Notify a child process of a fork.

Public Member Functions inherited from gem5::statistics::Group
	Group (Group parent, const char name=nullptr)
	Construct a new statistics group.

virtual	~Group ()

virtual void	regStats ()
	Callback to set stat parameters.

virtual void	resetStats ()
	Callback to reset stats.

virtual void	preDumpStats ()
	Callback before stats are dumped.

void	addStat (statistics::Info *info)
	Register a stat with this group.

const std::map< std::string, Group * > &	getStatGroups () const
	Get all child groups associated with this object.

const std::vector< Info * > &	getStats () const
	Get all stats associated with this object.

void	addStatGroup (const char name, Group block)
	Add a stat block as a child of this block.

const Info *	resolveStat (std::string name) const
	Resolve a stat by its name within this group.

void	mergeStatGroup (Group *block)
	Merge the contents (stats & children) of a block to this block.

	Group ()=delete

	Group (const Group &)=delete

Group &	operator= (const Group &)=delete

Public Member Functions inherited from gem5::Named
	Named (const std::string &name_)

virtual	~Named ()=default

virtual std::string	name () const

Public Member Functions inherited from gem5::Clocked
void	updateClockPeriod ()
	Update the tick to the current tick.

Tick	clockEdge (Cycles cycles=Cycles(0)) const
	Determine the tick when a cycle begins, by default the current one, but the argument also enables the caller to determine a future cycle.

Cycles	curCycle () const
	Determine the current cycle, corresponding to a tick aligned to a clock edge.

Tick	nextCycle () const
	Based on the clock of the object, determine the start tick of the first cycle that is at least one cycle in the future.

uint64_t	frequency () const

Tick	clockPeriod () const

double	voltage () const

Cycles	ticksToCycles (Tick t) const

Tick	cyclesToTicks (Cycles c) const

Protected Member Functions
std::shared_ptr< BaseGen >	nextGenerator () override

Protected Member Functions inherited from gem5::BaseTrafficGen
void	start ()

Protected Member Functions inherited from gem5::Drainable
	Drainable ()

virtual	~Drainable ()

virtual void	drainResume ()
	Resume execution after a successful drain.

void	signalDrainDone () const
	Signal that an object is drained.

Protected Member Functions inherited from gem5::Clocked
	Clocked (ClockDomain &clk_domain)
	Create a clocked object and set the clock domain based on the parameters.

	Clocked (Clocked &)=delete

Clocked &	operator= (Clocked &)=delete

virtual	~Clocked ()
	Virtual destructor due to inheritance.

void	resetClock () const
	Reset the object's clock using the current global tick value.

virtual void	clockPeriodUpdated ()
	A hook subclasses can implement so they can do any extra work that's needed when the clock rate is changed.

Private Member Functions
std::string	resolveFile (const std::string &name)
	Resolve a file path in the configuration file.

void	parseConfig ()
	Parse the config file and build the state map and transition matrix.

size_t	nextState ()
	Use the transition matrix to find the next state index.

Private Attributes
const std::string	configFile
	The config file to parse.

std::vector< std::vector< double > >	transitionMatrix
	State transition matrix.

uint32_t	currState
	Index of the current state.

std::unordered_map< uint32_t, std::shared_ptr< BaseGen > >	states
	Map of generator states.

Additional Inherited Members
Public Types inherited from gem5::ClockedObject
using	Params = ClockedObjectParams
	Parameters of ClockedObject.

Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params

Static Public Member Functions inherited from gem5::SimObject
static void	serializeAll (const std::string &cpt_dir)
	Create a checkpoint by serializing all SimObjects in the system.

static SimObject *	find (const char *name)
	Find the SimObject with the given name and return a pointer to it.

static void	setSimObjectResolver (SimObjectResolver *resolver)
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.

static SimObjectResolver *	getSimObjectResolver ()
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.

Static Public Member Functions inherited from gem5::Serializable
static const std::string &	currentSection ()
	Gets the fully-qualified name of the active section.

static void	generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
	Generate a checkpoint file so that the serialization can be routed to it.

Public Attributes inherited from gem5::ClockedObject
PowerState *	powerState

Protected Attributes inherited from gem5::BaseTrafficGen
System *const	system
	The system used to determine which mode we are currently operating in.

const bool	elasticReq
	Determine whether to add elasticity in the request injection, thus responding to backpressure by slowing things down.

const Tick	progressCheck
	Time to tolerate waiting for retries (not making progress), until we declare things broken.

std::unordered_map< RequestPtr, Tick >	waitingResp
	Reqs waiting for response.

gem5::BaseTrafficGen::StatGroup	stats

const RequestorID	requestorId
	RequestorID used in generated requests.

std::shared_ptr< BaseGen >	activeGenerator
	Currently active generator.

std::unique_ptr< StreamGen >	streamGenerator
	Stream/SubstreamID Generator.

Protected Attributes inherited from gem5::SimObject
const SimObjectParams &	_params
	Cached copy of the object parameters.

Protected Attributes inherited from gem5::EventManager
EventQueue *	eventq
	A pointer to this object's event queue.

Detailed Description

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.

Definition at line 70 of file traffic_gen.hh.

Constructor & Destructor Documentation

◆ TrafficGen()

gem5::TrafficGen::TrafficGen ( const TrafficGenParams & p )

Definition at line 56 of file traffic_gen.cc.

◆ ~TrafficGen()

gem5::TrafficGen::~TrafficGen ( )

inline

Definition at line 129 of file traffic_gen.hh.

Member Function Documentation

◆ init()

void gem5::TrafficGen::init ( )

overridevirtual

init() is called after all C++ SimObjects have been created and all ports are connected.

Initializations that are independent of unserialization but rely on a fully instantiated and connected SimObject graph should be done here.

Reimplemented from gem5::BaseTrafficGen.

Definition at line 64 of file traffic_gen.cc.

References gem5::BaseTrafficGen::init(), and parseConfig().

◆ initState()

void gem5::TrafficGen::initState ( )

overridevirtual

initState() is called on each SimObject when not restoring from a checkpoint.

This provides a hook for state initializations that are only required for a "cold start".

Reimplemented from gem5::SimObject.

Definition at line 72 of file traffic_gen.cc.

References DPRINTF, gem5::SimObject::initState(), gem5::System::isTimingMode(), gem5::BaseTrafficGen::start(), and gem5::BaseTrafficGen::system.

◆ nextGenerator()

std::shared_ptr< BaseGen > gem5::TrafficGen::nextGenerator ( )

overrideprotectedvirtual

Implements gem5::BaseTrafficGen.

Definition at line 393 of file traffic_gen.cc.

References gem5::BaseTrafficGen::activeGenerator, currState, DPRINTF, nextState(), and states.

◆ nextState()

size_t gem5::TrafficGen::nextState ( )

private

Use the transition matrix to find the next state index.

Definition at line 378 of file traffic_gen.cc.

References currState, gem5::ArmISA::i, gem5::MipsISA::p, gem5::Random::random(), gem5::random_mt, and transitionMatrix.

Referenced by nextGenerator().

◆ parseConfig()

void gem5::TrafficGen::parseConfig ( )

private

Parse the config file and build the state map and transition matrix.

Definition at line 127 of file traffic_gen.cc.

Referenced by init().

◆ resolveFile()

std::string gem5::TrafficGen::resolveFile ( const std::string & name )

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.

Parameters

name	Path to resolve

Definition at line 106 of file traffic_gen.cc.

References configFile, gem5::csprintf(), and gem5::Named::name().

Referenced by parseConfig().

◆ serialize()

void gem5::TrafficGen::serialize ( CheckpointOut & cp ) const

overridevirtual

Serialize an object.

Output an object's state into the current checkpoint section.

Parameters

cp	Checkpoint state

Reimplemented from gem5::BaseTrafficGen.

Definition at line 87 of file traffic_gen.cc.

References currState, gem5::BaseTrafficGen::serialize(), and SERIALIZE_SCALAR.

◆ unserialize()

void gem5::TrafficGen::unserialize ( CheckpointIn & cp )

overridevirtual

Unserialize an object.

Read an object's state from the current checkpoint section.

Parameters

cp	Checkpoint state

Reimplemented from gem5::BaseTrafficGen.

Definition at line 95 of file traffic_gen.cc.

References currState, gem5::BaseTrafficGen::unserialize(), and UNSERIALIZE_SCALAR.

Member Data Documentation

◆ configFile

const std::string gem5::TrafficGen::configFile

private

The config file to parse.

Definition at line 76 of file traffic_gen.hh.

Referenced by parseConfig(), and resolveFile().

◆ currState

uint32_t gem5::TrafficGen::currState

private

Index of the current state.

Definition at line 117 of file traffic_gen.hh.

Referenced by nextGenerator(), nextState(), parseConfig(), serialize(), and unserialize().

◆ states

std::unordered_map<uint32_t, std::shared_ptr<BaseGen> > gem5::TrafficGen::states

private

Map of generator states.

Definition at line 120 of file traffic_gen.hh.

Referenced by nextGenerator(), and parseConfig().

◆ transitionMatrix

std::vector<std::vector<double> > gem5::TrafficGen::transitionMatrix

private

State transition matrix.

Definition at line 114 of file traffic_gen.hh.

Referenced by nextState(), and parseConfig().

The documentation for this class was generated from the following files:

cpu/testers/traffic_gen/traffic_gen.hh
cpu/testers/traffic_gen/traffic_gen.cc

Classes

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ TrafficGen()

◆ ~TrafficGen()

Member Function Documentation

◆ init()

◆ initState()

◆ nextGenerator()

◆ nextState()

◆ parseConfig()

◆ resolveFile()

◆ serialize()

◆ unserialize()

Member Data Documentation

◆ configFile

◆ currState

◆ states

◆ transitionMatrix