The traffic generator is a master module that generates stimuli for the memory system, based on a collection of simple generator behaviours that are either probabilistic or based on traces. More...

#include <traffic_gen.hh>

Inheritance diagram for TrafficGen:

Classes
class	TrafficGenPort
	Master port specialisation for the traffic generator. More...

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

Public Member Functions
	TrafficGen (const TrafficGenParams *p)

	~TrafficGen ()

BaseMasterPort &	getMasterPort (const std::string &if_name, PortID idx=InvalidPortID) override
	Get a master port with a given name and index. More...

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

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

DrainState	drain () override
	Notify an object that it needs to drain its state. More...

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

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

void	regStats () override
	Register statistics. More...

Public Member Functions inherited from MemObject
const Params *	params () const

	MemObject (const Params *params)

virtual BaseSlavePort &	getSlavePort (const std::string &if_name, PortID idx=InvalidPortID)
	Get a slave port with a given name and index. More...

Public Member Functions inherited from ClockedObject
	ClockedObject (const ClockedObjectParams *p)

const Params *	params () const

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

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

Enums::PwrState	pwrState () const

std::string	pwrStateName () const

std::vector< double >	pwrStateWeights () const
	Returns the percentage residency for each power state. More...

void	computeStats ()
	Record stats values like state residency by computing the time difference from previous update. More...

void	pwrState (Enums::PwrState)

void	regStats () override
	Register statistics for this object. More...

Public Member Functions inherited from SimObject
const Params *	params () const

	SimObject (const Params *_params)

virtual	~SimObject ()

virtual const std::string	name () const

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

virtual void	resetStats ()
	Reset statistics associated with this object. More...

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

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

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

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

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

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

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

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

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

Public Member Functions inherited from EventManager
	EventManager (EventManager &em)

	EventManager (EventManager *em)

	EventManager (EventQueue *eq)

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)

void	setCurTick (Tick newVal)

Public Member Functions inherited from Serializable
	Serializable ()

virtual	~Serializable ()

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

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

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

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

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

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

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

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. More...

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

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. More...

uint64_t	frequency () const

Tick	clockPeriod () const

double	voltage () const

Cycles	ticksToCycles (Tick t) const

Tick	cyclesToTicks (Cycles c) const

Private Member Functions
void	transition ()
	Determine next state and perform the transition. More...

void	enterState (uint32_t newState)
	Enter a new state. More...

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

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

void	update ()
	Schedules event for next update and executes an update on the state graph, either performing a state transition or executing the current state, depending on the current time. More...

void	recvReqRetry ()
	Receive a retry from the neighbouring port and attempt to resend the waiting packet. More...

void	noProgress ()
	Method to inform the user we have made no progress. More...

Private Attributes
System *	system
	The system used to determine which mode we are currently operating in. More...

MasterID	masterID
	MasterID used in generated requests. More...

const std::string	configFile
	The config file to parse. More...

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

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

EventWrapper< TrafficGen,&TrafficGen::noProgress >	noProgressEvent
	Event to keep track of our progress, or lack thereof. More...

Tick	nextTransitionTick
	Time of next transition. More...

Tick	nextPacketTick
	Time of the next packet. More...

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

uint32_t	currState
	Index of the current state. More...

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

TrafficGenPort	port
	The instance of master port used by the traffic generator. More...

PacketPtr	retryPkt
	Packet waiting to be sent. More...

Tick	retryPktTick
	Tick when the stalled packet was meant to be sent. More...

EventWrapper< TrafficGen,&TrafficGen::update >	updateEvent
	Event for scheduling updates. More...

uint64_t	numSuppressed

Stats::Scalar	numPackets
	Count the number of generated packets. More...

Stats::Scalar	numRetries
	Count the number of retries. More...

Stats::Scalar	retryTicks
	Count the time incurred from back-pressure. More...

Additional Inherited Members
Public Types inherited from MemObject
typedef MemObjectParams	Params

Public Types inherited from ClockedObject
typedef ClockedObjectParams	Params
	Parameters of ClockedObject. More...

Public Types inherited from SimObject
typedef SimObjectParams	Params

Static Public Member Functions inherited from SimObject
static void	serializeAll (CheckpointOut &cp)
	Serialize all SimObjects in the system. More...

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

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

static void	serializeAll (const std::string &cpt_dir)

static void	unserializeGlobals (CheckpointIn &cp)

Static Public Attributes inherited from Serializable
static int	ckptCount = 0

static int	ckptMaxCount = 0

static int	ckptPrevCount = -1

Protected Member Functions inherited from Drainable
	Drainable ()

virtual	~Drainable ()

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

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

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

	Clocked (Clocked &)=delete

Clocked &	operator= (Clocked &)=delete

virtual	~Clocked ()
	Virtual destructor due to inheritance. More...

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

Protected Attributes inherited from ClockedObject
Enums::PwrState	_currPwrState
	To keep track of the current power state. More...

Tick	prvEvalTick

Stats::Scalar	numPwrStateTransitions

Stats::Distribution	pwrStateClkGateDist

Stats::Vector	pwrStateResidencyTicks

Protected Attributes inherited from SimObject
const SimObjectParams *	_params
	Cached copy of the object parameters. More...

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

Detailed Description

The traffic generator is a master module that generates stimuli for the memory system, based on a collection of simple generator 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.

Definition at line 61 of file traffic_gen.hh.

Constructor & Destructor Documentation

TrafficGen::TrafficGen ( const TrafficGenParams * p )

Definition at line 57 of file traffic_gen.cc.

TrafficGen::~TrafficGen ( )

inline

Definition at line 226 of file traffic_gen.hh.

Member Function Documentation

DrainState TrafficGen::drain ( )

overridevirtual

Notify an object that it needs to drain its state.

If the object does not need further simulation to drain internal buffers, it returns DrainState::Drained and automatically switches to the Drained state. If the object needs more simulation, it returns DrainState::Draining and automatically enters the Draining state. Other return values are invalid.

Note: An object that has entered the Drained state can be disturbed by other objects in the system and consequently stop being drained. These perturbations are not visible in the drain state. The simulator therefore repeats the draining process until all objects return DrainState::Drained on the first call to drain().

Returns: DrainState::Drained if the object is drained at this point in time, DrainState::Draining if it needs further simulation.

Implements Drainable.

Definition at line 127 of file traffic_gen.cc.

References EventManager::deschedule(), Drained, Draining, MaxTick, nextPacketTick, nextTransitionTick, retryPkt, Event::scheduled(), and updateEvent.

void TrafficGen::enterState ( uint32_t newState )

private

Enter a new state.

Parameters

newState identifier of state to enter

Definition at line 499 of file traffic_gen.cc.

References currState, curTick(), DPRINTF, nextTransitionTick, and states.

Referenced by init(), and transition().

BaseMasterPort & TrafficGen::getMasterPort	(	const std::string &	if_name,
		PortID	idx = `InvalidPortID`
	)

overridevirtual

Get a master port with a given name and index.

This is used at binding time and returns a reference to a protocol-agnostic base master port.

Parameters

if_name	Port name
idx	Index in the case of a VectorPort

Returns: A reference to the given port

Reimplemented from MemObject.

Definition at line 83 of file traffic_gen.cc.

References MemObject::getMasterPort(), and port.

void 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 SimObject.

Definition at line 93 of file traffic_gen.cc.

References currState, DPRINTF, enterState(), fatal, BaseMasterPort::isConnected(), System::isTimingMode(), SimObject::name(), parseConfig(), port, and system.

void 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 SimObject.

Definition at line 113 of file traffic_gen.cc.

References currState, DPRINTF, elasticReq, System::isTimingMode(), nextPacketTick, nextTransitionTick, EventManager::schedule(), states, system, and updateEvent.

void TrafficGen::noProgress ( )

private

Method to inform the user we have made no progress.

Definition at line 545 of file traffic_gen.cc.

References fatal, SimObject::name(), and progressCheck.

void TrafficGen::parseConfig ( )

private

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

Definition at line 257 of file traffic_gen.cc.

References System::cacheLineSize(), configFile, currState, divCeil(), DPRINTF, fatal, TrafficGen::Transition::from, ArmISA::i, SparcISA::id, MipsISA::is, ArmISA::j, masterID, ArmISA::mode, SimObject::name(), TrafficGen::Transition::p, resolveFile(), states, Stats::sum(), system, ArmISA::t, TrafficGen::Transition::to, transition(), transitionMatrix, and warn.

Referenced by init().

void TrafficGen::recvReqRetry ( )

private

Receive a retry from the neighbouring port and attempt to resend the waiting packet.

Definition at line 512 of file traffic_gen.cc.

References currState, curTick(), DPRINTF, Draining, Drainable::drainState(), elasticReq, MaxTick, nextPacketTick, nextTransitionTick, numRetries, port, retryPkt, retryPktTick, retryTicks, EventManager::schedule(), MasterPort::sendTimingReq(), Drainable::signalDrainDone(), states, and updateEvent.

Referenced by TrafficGen::TrafficGenPort::recvReqRetry().

void TrafficGen::regStats ( )

overridevirtual

Register statistics.

Reimplemented from SimObject.

Definition at line 552 of file traffic_gen.cc.

References Stats::DataWrap< Derived, InfoProxyType >::desc(), SimObject::name(), Stats::DataWrap< Derived, InfoProxyType >::name(), numPackets, numRetries, ClockedObject::regStats(), and retryTicks.

std::string 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 236 of file traffic_gen.cc.

References configFile, csprintf(), and SimObject::name().

Referenced by parseConfig().

void TrafficGen::serialize ( CheckpointOut & cp ) const

overridevirtual

Serialize an object.

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

Parameters

cp	Checkpoint state

Implements Serializable.

Definition at line 146 of file traffic_gen.cc.

References currState, DPRINTF, nextPacketTick, nextTransitionTick, Event::scheduled(), SERIALIZE_SCALAR, updateEvent, and Event::when().

void TrafficGen::transition ( )

private

Determine next state and perform the transition.

Definition at line 480 of file traffic_gen.cc.

References currState, enterState(), ArmISA::i, MipsISA::p, Random::random(), random_mt, X86ISA::size(), states, and transitionMatrix.

Referenced by parseConfig(), and update().

void TrafficGen::unserialize ( CheckpointIn & cp )

overridevirtual

Unserialize an object.

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

Parameters

cp	Checkpoint state

Implements Serializable.

Definition at line 165 of file traffic_gen.cc.

References currState, nextPacketTick, nextTransitionTick, EventManager::schedule(), UNSERIALIZE_SCALAR, and updateEvent.

void TrafficGen::update ( )

private

Schedules event for next update and executes an update on the state graph, either performing a state transition or executing the current state, depending on the current time.

Definition at line 185 of file traffic_gen.cc.

References Packet::cmdString(), currState, curTick(), DPRINTF, elasticReq, Packet::getAddr(), System::isMemAddr(), SimObject::name(), nextPacketTick, nextTransitionTick, noProgressEvent, numPackets, numSuppressed, port, progressCheck, Packet::req, EventManager::reschedule(), retryPkt, retryPktTick, EventManager::schedule(), MasterPort::sendTimingReq(), states, system, transition(), updateEvent, and warn.