Base class used for synchronizing the simulation events to some real time "wall clock.". More...

#include <synchronizer.h>

Inheritance diagram for ns3::Synchronizer:

Collaboration diagram for ns3::Synchronizer:

Public Member Functions
	Synchronizer ()

virtual	~Synchronizer ()

uint64_t	EventEnd (void)
	Ask the synchronizer to return the time step between the instant remembered during EventStart and now. More...

void	EventStart (void)
	Ask the synchronizer to remember what time it is. More...

uint64_t	GetCurrentRealtime (void)
	Retrieve the value of the origin of the underlying normalized wall clock time in simulator timestep units. More...

int64_t	GetDrift (uint64_t ts)
	Retrieve the difference between the real time clock used to synchronize the simulation and the simulation time (in simulator timestep units). More...

uint64_t	GetOrigin (void)
	Retrieve the value of the origin of the simulation time in simulator timestep units. More...

bool	Realtime (void)
	Return true if this synchronizer is actually synchronizing to a realtime clock. More...

void	SetCondition (bool)
	Set the condition variable that tells a possible simulator thread waiting in the Synchronize method that an event has happened which demands a reevaluation of the wait time. More...

void	SetOrigin (uint64_t ts)
	Establish a correspondence between a simulation time and the synchronizer real time. More...

void	Signal (void)
	Tell a possible simulator thread waiting in the Synchronize method that an event has happened which demands a reevaluation of the wait time. More...

bool	Synchronize (uint64_t tsCurrent, uint64_t tsDelay)
	Wait until the real time is in sync with the specified simulation time or until the synchronizer is Sigalled. More...

Public Member Functions inherited from ns3::Object
	Object ()

virtual	~Object ()

void	AggregateObject (Ptr< Object > other)

void	Dispose (void)
	Run the DoDispose methods of this object and all the objects aggregated to it. More...

AggregateIterator	GetAggregateIterator (void) const

virtual TypeId	GetInstanceTypeId (void) const

template<typename T >
Ptr< T >	GetObject (void) const

template<typename T >
Ptr< T >	GetObject (TypeId tid) const

void	Initialize (void)
	This method calls the virtual DoInitialize method on all the objects aggregated to this object. More...

Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
	SimpleRefCount ()
	Constructor. More...

	SimpleRefCount (const SimpleRefCount &o)
	Copy constructor. More...

uint32_t	GetReferenceCount (void) const
	Get the reference count of the object. More...

SimpleRefCount &	operator= (const SimpleRefCount &o)
	Assignment. More...

void	Ref (void) const
	Increment the reference count. More...

void	Unref (void) const
	Decrement the reference count. More...

Public Member Functions inherited from ns3::ObjectBase
virtual	~ObjectBase ()
	Virtual destructor. More...

void	GetAttribute (std::string name, AttributeValue &value) const

bool	GetAttributeFailSafe (std::string name, AttributeValue &attribute) const

void	SetAttribute (std::string name, const AttributeValue &value)

bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)

bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)

bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)

bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)

bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)

Static Public Member Functions
static TypeId	GetTypeId (void)

Static Public Member Functions inherited from ns3::Object
static TypeId	GetTypeId (void)
	Register this type. More...

Static Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
static void	Cleanup (void)
	Noop. More...

Static Public Member Functions inherited from ns3::ObjectBase
static TypeId	GetTypeId (void)
	Get the type ID. More...

Protected Member Functions
virtual uint64_t	DoEventEnd (void)=0

virtual void	DoEventStart (void)=0

virtual uint64_t	DoGetCurrentRealtime (void)=0
	Retrieve the value of the origin of the underlying normalized wall clock time in simulator timestep units. More...

virtual int64_t	DoGetDrift (uint64_t ns)=0
	Declaration of method used to retrieve drift between the real time clock used to synchronize the simulation and the current simulation time. More...

virtual bool	DoRealtime (void)=0
	Return true if this synchronizer is actually synchronizing to a realtime clock. More...

virtual void	DoSetCondition (bool)=0
	Declaration of the method used to set the condition variable that tells a possible simulator thread waiting in the Synchronize method that an event has happened which demands a reevaluation of the wait time. More...

virtual void	DoSetOrigin (uint64_t ns)=0
	Establish a correspondence between a simulation time and a wall-clock (real) time. More...

virtual void	DoSignal (void)=0
	Declaration of the method used to tell a possible simulator thread waiting in the DoSynchronize method that an event has happened which demands a reevaluation of the wait time. More...

virtual bool	DoSynchronize (uint64_t nsCurrent, uint64_t nsDelay)=0
	Wait until the real time is in sync with the specified simulation time. More...

Protected Member Functions inherited from ns3::Object
	Object (const Object &o)

virtual void	DoDispose (void)
	This method is called by Object::Dispose or by the object's destructor, whichever comes first. More...

virtual void	DoInitialize (void)
	This method is called only once by Object::Initialize. More...

virtual void	NotifyNewAggregate (void)
	This method is invoked whenever two sets of objects are aggregated together. More...

Protected Member Functions inherited from ns3::ObjectBase
void	ConstructSelf (const AttributeConstructionList &attributes)

virtual void	NotifyConstructionCompleted (void)
	This method is invoked once all member attributes have been initialized. More...

Protected Attributes
uint64_t	m_realtimeOriginNano

uint64_t	m_simOriginNano

Private Member Functions
uint64_t	NanosecondToTimeStep (uint64_t ns)
	Convert a normalized nanosecond count into a simulator time step (which can be steps of time in a user-specified unit). More...

uint64_t	TimeStepToNanosecond (uint64_t ts)
	Convert a simulator time step (which can be steps of time in a user-specified unit) to a normalized time step in nanosecond units. More...

Detailed Description

Base class used for synchronizing the simulation events to some real time "wall clock.".

Doxygen introspection did not find any typical Config paths.

The simulation clock is maintained as a 64-bit integer in a unit specified by the user through the TimeStepPrecision::Set function. This means that it is not possible to specify event expiration times with anything better than this user-specified accuracy. We use this clock for the simulation time.

The real-time clock is maintained as a 64-bit integer count of nanoseconds.

The synchronization between the simulation clock and the real-time clock is maintained using a combination of sleep-waiting, busy-waiting and a feedback loop.

No Attributes are defined for this type.
No TraceSources are defined for this type.

Definition at line 44 of file synchronizer.h.

Constructor & Destructor Documentation

ns3::Synchronizer::Synchronizer ( )

Definition at line 38 of file synchronizer.cc.

References NS_LOG_FUNCTION.

ns3::Synchronizer::~Synchronizer ( )

virtual

Definition at line 44 of file synchronizer.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

virtual uint64_t ns3::Synchronizer::DoEventEnd ( void )

protectedpure virtual

Implemented in ns3::WallClockSynchronizer.

Referenced by EventEnd().

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virtual void ns3::Synchronizer::DoEventStart ( void )

protectedpure virtual

Implemented in ns3::WallClockSynchronizer.

Referenced by EventStart().

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virtual uint64_t ns3::Synchronizer::DoGetCurrentRealtime ( void )

protectedpure virtual

Retrieve the value of the origin of the underlying normalized wall clock time in simulator timestep units.

Internal:

Subclasses are expected to implement this method to do the actual real-time-clock-specific work of getting the current time.

Returns: The normalized wall clock time (in nanosecond units).

See also: TimeStepPrecision::Get; Synchronizer::SetOrigin

Implemented in ns3::WallClockSynchronizer.

Referenced by GetCurrentRealtime().

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virtual int64_t ns3::Synchronizer::DoGetDrift ( uint64_t ns )

protectedpure virtual

Declaration of method used to retrieve drift between the real time clock used to synchronize the simulation and the current simulation time.

Internal:

Parameters

ns	Simulation timestep from the simulator normalized to nanosecond steps.

Returns: Drift in nanosecond units.

See also: TimeStepPrecision::Get; Synchronizer::SetOrigin; Synchronizer::GetDrift

Implemented in ns3::WallClockSynchronizer.

Referenced by GetDrift().

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virtual bool ns3::Synchronizer::DoRealtime ( void )

protectedpure virtual

Return true if this synchronizer is actually synchronizing to a realtime clock.

The simulator sometimes needs to know this.

Internal:

Subclasses are expected to implement this method to tell the outside world whether or not they are synchronizing to a realtime clock.

Returns: True if locked with realtime, false if not.

Implemented in ns3::WallClockSynchronizer.

Referenced by Realtime().

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virtual void ns3::Synchronizer::DoSetCondition ( bool )

protectedpure virtual

Declaration of the method used to set the condition variable that tells a possible simulator thread waiting in the Synchronize method that an event has happened which demands a reevaluation of the wait time.

See also: Synchronizer::SetCondition

Implemented in ns3::WallClockSynchronizer.

Referenced by SetCondition().

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virtual void ns3::Synchronizer::DoSetOrigin ( uint64_t ns )

protectedpure virtual

Establish a correspondence between a simulation time and a wall-clock (real) time.

Internal:

There are three timelines involved here: the simulation time, the (absolute) wall-clock time and the (relative) synchronizer real time. Calling this method makes a correspondence between the origin of the synchronizer time and the current wall-clock time.

This method is expected to be called at the "instant" before simulation begins. At this point, simulation time = 0, and synchronizer time is set = 0 in this method. We then associate this time with the current value of the real time clock that will be used to actually perform the synchronization.

Subclasses are expected to implement this method to do the actual real-time-clock-specific work of making the correspondence mentioned above. for example, this is where the differences between Time parameters and parameters to clock_nanosleep would be dealt with.

Parameters

ns	The simulation time we need to use as the origin (normalized to nanosecond units).

See also: Synchronizer::SetOrigin; TimeStepPrecision::Get

Implemented in ns3::WallClockSynchronizer.

Referenced by SetOrigin().

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virtual void ns3::Synchronizer::DoSignal ( void )

protectedpure virtual

Declaration of the method used to tell a possible simulator thread waiting in the DoSynchronize method that an event has happened which demands a reevaluation of the wait time.

See also: Synchronizer::Signal

Implemented in ns3::WallClockSynchronizer.

Referenced by Signal().

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virtual bool ns3::Synchronizer::DoSynchronize	(	uint64_t	nsCurrent,
		uint64_t	nsDelay
	)

protectedpure virtual

Wait until the real time is in sync with the specified simulation time.

Internal:

This is where the real work of synchronization is done. The Time passed in as a parameter is the simulation time. The job of Synchronize is to translate from simulation time to synchronizer time (in a perfect world this is the same time) and then figure out how long in real-time it needs to wait until that synchronizer / simulation time comes around.

Subclasses are expected to implement this method to do the actual real-time-clock-specific work of waiting (either busy-waiting or sleeping, or some combination) until the requested simulation time.

Parameters

nsCurrent	The current simulation time (normalized to nanosecond units).
nsDelay	The simulation time we need to wait for (normalized to nanosecond units).

Returns: True if the function ran to completion, false if it was interrupted by a Signal.

See also: Synchronizer::Synchronize; TimeStepPrecision::Get; Synchronizer::Signal

Implemented in ns3::WallClockSynchronizer.

Referenced by Synchronize().

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uint64_t ns3::Synchronizer::EventEnd ( void )

Ask the synchronizer to return the time step between the instant remembered during EventStart and now.

Used in conjunction with EventStart to determine the real execution time of a simulation event.

See also: Synchronizer::EventStart; TimeStepPrecision::Get

Definition at line 122 of file synchronizer.cc.

References DoEventEnd(), NanosecondToTimeStep(), and NS_LOG_FUNCTION.

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void ns3::Synchronizer::EventStart ( void )

Ask the synchronizer to remember what time it is.

Typically used with EventEnd to determine the real execution time of a simulation event.

See also: Synchronizer::EventEnd; TimeStepPrecision::Get

Definition at line 115 of file synchronizer.cc.

References DoEventStart(), and NS_LOG_FUNCTION.

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uint64_t ns3::Synchronizer::GetCurrentRealtime ( void )

Retrieve the value of the origin of the underlying normalized wall clock time in simulator timestep units.

Returns: The normalized wall clock time (in simulator timestep units).

See also: TimeStepPrecision::Get; Synchronizer::SetOrigin

Definition at line 57 of file synchronizer.cc.

References DoGetCurrentRealtime(), NanosecondToTimeStep(), and NS_LOG_FUNCTION.

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int64_t ns3::Synchronizer::GetDrift ( uint64_t ts )

Retrieve the difference between the real time clock used to synchronize the simulation and the simulation time (in simulator timestep units).

Parameters

ts	Simulation timestep from the simulator interpreted as current time in the simulator.

Returns: Simulation timestep (in simulator timestep units) minus origin time (stored internally in nanosecond units).

See also: TimeStepPrecision::Get; Synchronizer::SetOrigin; Synchronizer::DoGetDrift

Definition at line 79 of file synchronizer.cc.

References DoGetDrift(), NanosecondToTimeStep(), NS_LOG_FUNCTION, and TimeStepToNanosecond().

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uint64_t ns3::Synchronizer::GetOrigin ( void )

Retrieve the value of the origin of the simulation time in simulator timestep units.

Returns: The simulation time used as the origin (in simulator timestep units).

See also: TimeStepPrecision::Get; Synchronizer::SetOrigin

Definition at line 72 of file synchronizer.cc.

References m_simOriginNano, NanosecondToTimeStep(), and NS_LOG_FUNCTION.

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TypeId ns3::Synchronizer::GetTypeId ( void )

static

Definition at line 30 of file synchronizer.cc.

References ns3::TypeId::SetParent().

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uint64_t ns3::Synchronizer::NanosecondToTimeStep ( uint64_t ns )

private

Convert a normalized nanosecond count into a simulator time step (which can be steps of time in a user-specified unit).

Internal:

Parameters

ns	The nanosecond count step to be converted

Returns: The simulation time step to be interpreted in appropriate units.

See also: TimeStepPrecision::Get

Definition at line 136 of file synchronizer.cc.

References NS_LOG_FUNCTION.

Referenced by EventEnd(), GetCurrentRealtime(), GetDrift(), and GetOrigin().

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bool ns3::Synchronizer::Realtime ( void )

Return true if this synchronizer is actually synchronizing to a realtime clock.

The simulator sometimes needs to know this.

Returns: True if locked with realtime, false if not.

Definition at line 50 of file synchronizer.cc.

References DoRealtime(), and NS_LOG_FUNCTION.

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void ns3::Synchronizer::SetCondition ( bool cond )

Set the condition variable that tells a possible simulator thread waiting in the Synchronize method that an event has happened which demands a reevaluation of the wait time.

See also: Synchronizer::Signal

Definition at line 108 of file synchronizer.cc.

References DoSetCondition(), and NS_LOG_FUNCTION.

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void ns3::Synchronizer::SetOrigin ( uint64_t ts )

Establish a correspondence between a simulation time and the synchronizer real time.

This method is expected to be called at the "instant" before simulation begins. At this point, simulation time = 0, and a set = 0 in this method. We then associate this time with the current value of the real time clock that will be used to actually perform the synchronization.

Subclasses are expected to implement the corresponding DoSetOrigin pure virtual method to do the actual real-time-clock-specific work of making the correspondence mentioned above.

Parameters

ts	The simulation time we should use as the origin (in simulator timestep units).

See also: TimeStepPrecision::Get; TimeStepPrecision::DoSetOrigin

Definition at line 64 of file synchronizer.cc.

References DoSetOrigin(), m_simOriginNano, NS_LOG_FUNCTION, and TimeStepToNanosecond().

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void ns3::Synchronizer::Signal ( void )

Tell a possible simulator thread waiting in the Synchronize method that an event has happened which demands a reevaluation of the wait time.

This will cause the thread to wake and return to the simulator proper where it can get its bearings.

See also: Synchronizer::Synchronize; Synchronizer::DoSignal

Definition at line 101 of file synchronizer.cc.

References DoSignal(), and NS_LOG_FUNCTION.

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bool ns3::Synchronizer::Synchronize	(	uint64_t	tsCurrent,
		uint64_t	tsDelay
	)

Wait until the real time is in sync with the specified simulation time or until the synchronizer is Sigalled.

This is where the real work of synchronization is done. The Time passed in as a parameter is the simulation time. The job of Synchronize is to translate from simulation time to synchronizer time (in a perfect world this is the same time) and then figure out how long in real-time it needs to wait until that synchronizer / simulation time comes around.

Subclasses are expected to implement the corresponding DoSynchronize pure virtual method to do the actual real-time-clock-specific work of waiting (either busy-waiting or sleeping, or some combination thereof) until the requested simulation time.

Parameters