Linux pfifo_fast is the default priority queue enabled on Linux systems. More...

#include "pfifo-fast-queue-disc.h"

Inheritance diagram for ns3::PfifoFastQueueDisc:

Collaboration diagram for ns3::PfifoFastQueueDisc:

Public Member Functions
	PfifoFastQueueDisc ()
	PfifoFastQueueDisc constructor.

	~PfifoFastQueueDisc () override

Public Member Functions inherited from ns3::QueueDisc
	QueueDisc (const QueueDisc &)=delete

	QueueDisc (QueueDiscSizePolicy policy, QueueSizeUnit unit)
	Constructor.

	QueueDisc (QueueDiscSizePolicy policy=QueueDiscSizePolicy::SINGLE_INTERNAL_QUEUE)
	Constructor.

	~QueueDisc () override

void	AddInternalQueue (Ptr< InternalQueue > queue)
	Add an internal queue to the tail of the list of queues.

void	AddPacketFilter (Ptr< PacketFilter > filter)
	Add a packet filter to the tail of the list of filters used to classify packets.

void	AddQueueDiscClass (Ptr< QueueDiscClass > qdClass)
	Add a queue disc class to the tail of the list of classes.

int32_t	Classify (Ptr< QueueDiscItem > item)
	Classify a packet by calling the packet filters, one at a time, until either a filter able to classify the packet is found or all the filters have been processed.

Ptr< QueueDiscItem >	Dequeue ()
	Extract from the queue disc the packet that has been dequeued by calling Peek, if any, or call the private DoDequeue method (which must be implemented by derived classes) to dequeue a packet, otherwise.

bool	Enqueue (Ptr< QueueDiscItem > item)
	Pass a packet to store to the queue discipline.

QueueSize	GetCurrentSize () const
	Get the current size of the queue disc in bytes, if operating in bytes mode, or packets, otherwise.

Ptr< InternalQueue >	GetInternalQueue (std::size_t i) const
	Get the i-th internal queue.

QueueSize	GetMaxSize () const
	Get the maximum size of the queue disc.

uint32_t	GetNBytes () const
	Get the amount of bytes stored by the queue disc.

Ptr< NetDeviceQueueInterface >	GetNetDeviceQueueInterface () const

std::size_t	GetNInternalQueues () const
	Get the number of internal queues.

std::size_t	GetNPacketFilters () const
	Get the number of packet filters.

uint32_t	GetNPackets () const
	Get the number of packets stored by the queue disc.

std::size_t	GetNQueueDiscClasses () const
	Get the number of queue disc classes.

Ptr< PacketFilter >	GetPacketFilter (std::size_t i) const
	Get the i-th packet filter.

Ptr< QueueDiscClass >	GetQueueDiscClass (std::size_t i) const
	Get the i-th queue disc class.

virtual uint32_t	GetQuota () const
	Get the maximum number of dequeue operations following a packet enqueue.

SendCallback	GetSendCallback () const

const Stats &	GetStats ()
	Retrieve all the collected statistics.

virtual WakeMode	GetWakeMode () const
	When setting up the wake callbacks on the netdevice queues, it is necessary to determine which queue disc (the root queue disc or one of its children) should be activated when the netdevice wakes one of its transmission queues.

QueueDisc &	operator= (const QueueDisc &)=delete

Ptr< const QueueDiscItem >	Peek ()
	Get a copy of the next packet the queue discipline will extract.

void	Run ()
	Modelled after the Linux function __qdisc_run (net/sched/sch_generic.c) Dequeues multiple packets, until a quota is exceeded or sending a packet to the device failed.

bool	SetMaxSize (QueueSize size)
	Set the maximum size of the queue disc.

void	SetNetDeviceQueueInterface (Ptr< NetDeviceQueueInterface > ndqi)

virtual void	SetQuota (const uint32_t quota)
	Set the maximum number of dequeue operations following a packet enqueue.

void	SetSendCallback (SendCallback func)

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

	~Object () override
	Destructor.

void	AggregateObject (Ptr< Object > other)
	Aggregate two Objects together.

void	Dispose ()
	Dispose of this Object.

AggregateIterator	GetAggregateIterator () const
	Get an iterator to the Objects aggregated to this one.

TypeId	GetInstanceTypeId () const override
	Get the most derived TypeId for this Object.

template<typename T >
Ptr< T >	GetObject () const
	Get a pointer to the requested aggregated Object.

template<>
Ptr< Object >	GetObject () const
	Specialization of () for objects of type ns3::Object.

template<typename T >
Ptr< T >	GetObject (TypeId tid) const
	Get a pointer to the requested aggregated Object by TypeId.

template<>
Ptr< Object >	GetObject (TypeId tid) const
	Specialization of (TypeId tid) for objects of type ns3::Object.

void	Initialize ()
	Invoke DoInitialize on all Objects aggregated to this one.

bool	IsInitialized () const
	Check if the object has been initialized.

void	UnidirectionalAggregateObject (Ptr< Object > other)
	Aggregate an Object to another Object.

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

	SimpleRefCount (const SimpleRefCount &o)
	Copy constructor.

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

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

void	Ref () const
	Increment the reference count.

void	Unref () const
	Decrement the reference count.

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

void	GetAttribute (std::string name, AttributeValue &value, bool permissive=false) const
	Get the value of an attribute, raising fatal errors if unsuccessful.

bool	GetAttributeFailSafe (std::string name, AttributeValue &value) const
	Get the value of an attribute without raising errors.

void	SetAttribute (std::string name, const AttributeValue &value)
	Set a single attribute, raising fatal errors if unsuccessful.

bool	SetAttributeFailSafe (std::string name, const AttributeValue &value)
	Set a single attribute without raising errors.

bool	TraceConnect (std::string name, std::string context, const CallbackBase &cb)
	Connect a TraceSource to a Callback with a context.

bool	TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
	Connect a TraceSource to a Callback without a context.

bool	TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected with a context.

bool	TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
	Disconnect from a TraceSource a Callback previously connected without a context.

Static Public Member Functions
static TypeId	GetTypeId ()
	Get the type ID.

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

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

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

Static Public Attributes
static constexpr const char *	LIMIT_EXCEEDED_DROP
	Packet dropped due to queue disc limit exceeded.

Static Public Attributes inherited from ns3::QueueDisc
static constexpr const char *	CHILD_QUEUE_DISC_DROP
	Packet dropped by a child queue disc.

static constexpr const char *	CHILD_QUEUE_DISC_MARK
	Packet marked by a child queue disc.

static constexpr const char *	INTERNAL_QUEUE_DROP
	Packet dropped by an internal queue.

Private Member Functions
bool	CheckConfig () override
	Check whether the current configuration is correct.

Ptr< QueueDiscItem >	DoDequeue () override
	This function actually extracts a packet from the queue disc.

bool	DoEnqueue (Ptr< QueueDiscItem > item) override
	This function actually enqueues a packet into the queue disc.

Ptr< const QueueDiscItem >	DoPeek () override
	Return a copy of the next packet the queue disc will extract.

void	InitializeParams () override
	Initialize parameters (if any) before the first packet is enqueued.

Static Private Attributes
static const uint32_t	prio2band [16] = {1, 2, 2, 2, 1, 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1}
	Priority to band map.

Additional Inherited Members
Public Types inherited from ns3::QueueDisc
typedef Queue< QueueDiscItem >	InternalQueue
	Internal queues store QueueDiscItem objects.

typedef std::function< void(Ptr< QueueDiscItem >)>	SendCallback
	Callback invoked to send a packet to the receiving object when Run is called.

enum	WakeMode { WAKE_ROOT = 0x00 , WAKE_CHILD = 0x01 }
	Used to determine whether the queue disc itself or its children must be activated when a netdevice wakes a transmission queue. More...

Protected Member Functions inherited from ns3::QueueDisc
void	DoDispose () override
	Dispose of the object.

void	DoInitialize () override
	Check whether the configuration is correct and initialize parameters.

void	DropAfterDequeue (Ptr< const QueueDiscItem > item, const char *reason)
	Perform the actions required when the queue disc is notified of a packet dropped after dequeue.

void	DropBeforeEnqueue (Ptr< const QueueDiscItem > item, const char *reason)
	Perform the actions required when the queue disc is notified of a packet dropped before enqueue.

bool	Mark (Ptr< QueueDiscItem > item, const char *reason)
	Marks the given packet and, if successful, updates the counters associated with the given reason.

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

virtual void	NotifyNewAggregate ()
	Notify all Objects aggregated to this one of a new Object being aggregated.

Protected Member Functions inherited from ns3::ObjectBase
void	ConstructSelf (const AttributeConstructionList &attributes)
	Complete construction of ObjectBase; invoked by derived classes.

virtual void	NotifyConstructionCompleted ()
	Notifier called once the ObjectBase is fully constructed.

Related Symbols inherited from ns3::ObjectBase
static TypeId	GetObjectIid ()
	Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly.

Detailed Description

Linux pfifo_fast is the default priority queue enabled on Linux systems.

Packets are enqueued in three FIFO droptail queues according to three priority bands based on the packet priority.

The system behaves similar to three ns3::DropTail queues operating together, in which packets from higher priority bands are always dequeued before a packet from a lower priority band is dequeued.

The queue disc capacity, i.e., the maximum number of packets that can be enqueued in the queue disc, is set through the limit attribute, which plays the same role as txqueuelen in Linux. If no internal queue is provided, three DropTail queues having each a capacity equal to limit are created by default. User is allowed to provide queues, but they must be three, operate in packet mode and each have a capacity not less than limit. No packet filter can be provided.

Definition at line 38 of file pfifo-fast-queue-disc.h.

Constructor & Destructor Documentation

◆ PfifoFastQueueDisc()

ns3::PfifoFastQueueDisc::PfifoFastQueueDisc ( )

PfifoFastQueueDisc constructor.

Creates a queue with a depth of 1000 packets per band by default

Definition at line 41 of file pfifo-fast-queue-disc.cc.

References NS_LOG_FUNCTION.

◆ ~PfifoFastQueueDisc()

ns3::PfifoFastQueueDisc::~PfifoFastQueueDisc ( )

override

Definition at line 47 of file pfifo-fast-queue-disc.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ CheckConfig()

bool ns3::PfifoFastQueueDisc::CheckConfig ( )

overrideprivatevirtual

Check whether the current configuration is correct.

Default objects (such as internal queues) might be created by this method to ensure the configuration is correct. This method is automatically called at simulation initialization time, and it is called before the InitializeParams () method. It is appropriate to promote parameter initialization to this method if it aids in checking for correct configuration.

See also: QueueDisc::InitializeParams

Returns: true if the configuration is correct, false otherwise

Implements ns3::QueueDisc.

Definition at line 133 of file pfifo-fast-queue-disc.cc.

References ns3::QueueDisc::AddInternalQueue(), ns3::ObjectFactory::Create(), ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetMaxSize(), ns3::QueueDisc::GetNInternalQueues(), ns3::QueueDisc::GetNPacketFilters(), ns3::QueueDisc::GetNQueueDiscClasses(), NS_LOG_ERROR, NS_LOG_FUNCTION, ns3::PACKETS, ns3::ObjectFactory::Set(), and ns3::ObjectFactory::SetTypeId().

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◆ DoDequeue()

Ptr< QueueDiscItem > ns3::PfifoFastQueueDisc::DoDequeue ( )

overrideprivatevirtual

This function actually extracts a packet from the queue disc.

Returns: 0 if the operation was not successful; the item otherwise.

Implements ns3::QueueDisc.

Definition at line 91 of file pfifo-fast-queue-disc.cc.

References ns3::QueueDisc::Dequeue(), ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetNInternalQueues(), ns3::QueueDisc::GetNPackets(), NS_LOG_FUNCTION, and NS_LOG_LOGIC.

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◆ DoEnqueue()

bool ns3::PfifoFastQueueDisc::DoEnqueue ( Ptr< QueueDiscItem > item )

overrideprivatevirtual

This function actually enqueues a packet into the queue disc.

Parameters

item	item to enqueue

Returns: True if the operation was successful; false otherwise

Implements ns3::QueueDisc.

Definition at line 55 of file pfifo-fast-queue-disc.cc.

References ns3::QueueDisc::DropBeforeEnqueue(), ns3::QueueDisc::GetCurrentSize(), ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetMaxSize(), ns3::QueueDisc::GetNPackets(), ns3::SocketPriorityTag::GetPriority(), LIMIT_EXCEEDED_DROP, NS_LOG_FUNCTION, NS_LOG_LOGIC, NS_LOG_WARN, and prio2band.

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◆ DoPeek()

Ptr< const QueueDiscItem > ns3::PfifoFastQueueDisc::DoPeek ( )

overrideprivatevirtual

Return a copy of the next packet the queue disc will extract.

The implementation of this method is based on the qdisc_peek_dequeued function of the Linux kernel, which dequeues a packet and retains it in the queue disc as a requeued packet. The packet is not traced as requeued, nor is the total count of requeued packets increased. The packet is still considered to be part of the queue disc and the dequeue trace is fired when Dequeue is called and the packet is actually extracted from the queue disc.

This approach is especially recommended for queue discs for which it is not obvious what is the next packet that will be dequeued (e.g., queue discs having multiple internal queues or child queue discs or queue discs that drop packets after dequeue). Subclasses can however provide their own implementation of this method that overrides the default one.

Returns: 0 if the operation was not successful; the packet otherwise.

Reimplemented from ns3::QueueDisc.

Definition at line 112 of file pfifo-fast-queue-disc.cc.

References ns3::QueueDisc::GetInternalQueue(), ns3::QueueDisc::GetNInternalQueues(), ns3::QueueDisc::GetNPackets(), NS_LOG_FUNCTION, NS_LOG_LOGIC, and ns3::QueueDisc::Peek().

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◆ GetTypeId()

TypeId ns3::PfifoFastQueueDisc::GetTypeId ( )

static

Get the type ID.

Returns: the object TypeId

Definition at line 26 of file pfifo-fast-queue-disc.cc.

References ns3::QueueDisc::GetMaxSize(), ns3::MakeQueueSizeAccessor(), ns3::MakeQueueSizeChecker(), ns3::QueueDisc::SetMaxSize(), and ns3::TypeId::SetParent().

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◆ InitializeParams()

void ns3::PfifoFastQueueDisc::InitializeParams ( )

overrideprivatevirtual

Initialize parameters (if any) before the first packet is enqueued.

This method is automatically called at simulation initialization time, after the CheckConfig() method has been called.

See also: QueueDisc::CheckConfig

Implements ns3::QueueDisc.

Definition at line 187 of file pfifo-fast-queue-disc.cc.

References NS_LOG_FUNCTION.

Member Data Documentation

◆ LIMIT_EXCEEDED_DROP

const char* ns3::PfifoFastQueueDisc::LIMIT_EXCEEDED_DROP

staticconstexpr

Initial value:

=

"Queue disc limit exceeded"

Packet dropped due to queue disc limit exceeded.

Definition at line 56 of file pfifo-fast-queue-disc.h.

Referenced by DoEnqueue().

◆ prio2band

const uint32_t ns3::PfifoFastQueueDisc::prio2band = {1, 2, 2, 2, 1, 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1}

staticprivate

Priority to band map.

Values are taken from the prio2band array used by the Linux pfifo_fast queue disc.

Definition at line 64 of file pfifo-fast-queue-disc.h.

Referenced by DoEnqueue().

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

src/traffic-control/model/pfifo-fast-queue-disc.h
src/traffic-control/model/pfifo-fast-queue-disc.cc

Public Member Functions

Static Public Member Functions

Static Public Attributes

Private Member Functions

Static Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ PfifoFastQueueDisc()

◆ ~PfifoFastQueueDisc()

Member Function Documentation

◆ CheckConfig()

◆ DoDequeue()

◆ DoEnqueue()

◆ DoPeek()

◆ GetTypeId()

◆ InitializeParams()

Member Data Documentation

◆ LIMIT_EXCEEDED_DROP

◆ prio2band