A Discrete-Event Network Simulator
API
ns3::PfifoFastQueueDisc Class Reference

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. More...
 
virtual ~PfifoFastQueueDisc ()
 
- Public Member Functions inherited from ns3::QueueDisc
 QueueDisc (QueueDiscSizePolicy policy=QueueDiscSizePolicy::SINGLE_INTERNAL_QUEUE)
 Constructor. More...
 
 QueueDisc (QueueDiscSizePolicy policy, QueueSizeUnit unit)
 Constructor. More...
 
virtual ~QueueDisc ()
 
void AddInternalQueue (Ptr< InternalQueue > queue)
 Add an internal queue to the tail of the list of queues. More...
 
void AddPacketFilter (Ptr< PacketFilter > filter)
 Add a packet filter to the tail of the list of filters used to classify packets. More...
 
void AddQueueDiscClass (Ptr< QueueDiscClass > qdClass)
 Add a queue disc class to the tail of the list of classes. More...
 
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. More...
 
Ptr< QueueDiscItemDequeue (void)
 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. More...
 
bool Enqueue (Ptr< QueueDiscItem > item)
 Pass a packet to store to the queue discipline. More...
 
QueueSize GetCurrentSize (void)
 Get the current size of the queue disc in bytes, if operating in bytes mode, or packets, otherwise. More...
 
Ptr< InternalQueueGetInternalQueue (std::size_t i) const
 Get the i-th internal queue. More...
 
QueueSize GetMaxSize (void) const
 Get the maximum size of the queue disc. More...
 
uint32_t GetNBytes (void) const
 Get the amount of bytes stored by the queue disc. More...
 
Ptr< NetDeviceQueueInterfaceGetNetDeviceQueueInterface (void) const
 
std::size_t GetNInternalQueues (void) const
 Get the number of internal queues. More...
 
std::size_t GetNPacketFilters (void) const
 Get the number of packet filters. More...
 
uint32_t GetNPackets (void) const
 Get the number of packets stored by the queue disc. More...
 
std::size_t GetNQueueDiscClasses (void) const
 Get the number of queue disc classes. More...
 
Ptr< PacketFilterGetPacketFilter (std::size_t i) const
 Get the i-th packet filter. More...
 
Ptr< QueueDiscClassGetQueueDiscClass (std::size_t i) const
 Get the i-th queue disc class. More...
 
virtual uint32_t GetQuota (void) const
 Get the maximum number of dequeue operations following a packet enqueue. More...
 
SendCallback GetSendCallback (void) const
 
const StatsGetStats (void)
 Retrieve all the collected statistics. More...
 
virtual WakeMode GetWakeMode (void) 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. More...
 
Ptr< const QueueDiscItemPeek (void)
 Get a copy of the next packet the queue discipline will extract. More...
 
void Run (void)
 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. More...
 
bool SetMaxSize (QueueSize size)
 Set the maximum size of the queue disc. More...
 
void SetNetDeviceQueueInterface (Ptr< NetDeviceQueueInterface > ndqi)
 
virtual void SetQuota (const uint32_t quota)
 Set the maximum number of dequeue operations following a packet enqueue. More...
 
void SetSendCallback (SendCallback func)
 
- Public Member Functions inherited from ns3::Object
 Object ()
 Constructor. More...
 
virtual ~Object ()
 Destructor. More...
 
void AggregateObject (Ptr< Object > other)
 Aggregate two Objects together. More...
 
void Dispose (void)
 Dispose of this Object. More...
 
AggregateIterator GetAggregateIterator (void) const
 Get an iterator to the Objects aggregated to this one. More...
 
virtual TypeId GetInstanceTypeId (void) const
 Get the most derived TypeId for this Object. More...
 
template<typename T >
Ptr< T > GetObject (void) const
 Get a pointer to the requested aggregated Object. More...
 
template<typename T >
Ptr< T > GetObject (TypeId tid) const
 Get a pointer to the requested aggregated Object by TypeId. More...
 
void Initialize (void)
 Invoke DoInitialize on all Objects aggregated to this one. More...
 
bool IsInitialized (void) const
 Check if the object has been initialized. More...
 
- Public Member Functions inherited from ns3::SimpleRefCount< Object, ObjectBase, ObjectDeleter >
 SimpleRefCount ()
 Default constructor. More...
 
 SimpleRefCount (const SimpleRefCount &o)
 Copy constructor. More...
 
uint32_t GetReferenceCount (void) const
 Get the reference count of the object. More...
 
SimpleRefCountoperator= (const SimpleRefCount &o)
 Assignment operator. 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
 Get the value of an attribute, raising fatal errors if unsuccessful. More...
 
bool GetAttributeFailSafe (std::string name, AttributeValue &value) const
 Get the value of an attribute without raising erros. More...
 
void SetAttribute (std::string name, const AttributeValue &value)
 Set a single attribute, raising fatal errors if unsuccessful. More...
 
bool SetAttributeFailSafe (std::string name, const AttributeValue &value)
 Set a single attribute without raising errors. More...
 
bool TraceConnect (std::string name, std::string context, const CallbackBase &cb)
 Connect a TraceSource to a Callback with a context. More...
 
bool TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
 Connect a TraceSource to a Callback without a context. More...
 
bool TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
 Disconnect from a TraceSource a Callback previously connected with a context. More...
 
bool TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
 Disconnect from a TraceSource a Callback previously connected without a context. More...
 

Static Public Member Functions

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

Static Public Attributes

static constexpr const char * LIMIT_EXCEEDED_DROP = "Queue disc limit exceeded"
 Packet dropped due to queue disc limit exceeded. More...
 
- Static Public Attributes inherited from ns3::QueueDisc
static constexpr const char * CHILD_QUEUE_DISC_DROP = "(Dropped by child queue disc) "
 Packet dropped by a child queue disc. More...
 
static constexpr const char * INTERNAL_QUEUE_DROP = "Dropped by internal queue"
 Packet dropped by an internal queue. More...
 

Private Member Functions

virtual bool CheckConfig (void)
 Check whether the current configuration is correct. More...
 
virtual Ptr< QueueDiscItemDoDequeue (void)
 This function actually extracts a packet from the queue disc. More...
 
virtual bool DoEnqueue (Ptr< QueueDiscItem > item)
 This function actually enqueues a packet into the queue disc. More...
 
virtual Ptr< const QueueDiscItemDoPeek (void)
 Return a copy of the next packet the queue disc will extract. More...
 
virtual void InitializeParams (void)
 Initialize parameters (if any) before the first packet is enqueued. More...
 

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. More...
 

Additional Inherited Members

- Public Types inherited from ns3::QueueDisc
typedef Queue< QueueDiscItemInternalQueue
 Internal queues store QueueDiscItem objects. More...
 
typedef std::function< void(Ptr< QueueDiscItem >)> SendCallback
 Callback invoked to send a packet to the receiving object when Run is called. More...
 
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
virtual void DoDispose (void)
 Dispose of the object. More...
 
void DoInitialize (void)
 Check whether the configuration is correct and initialize parameters. More...
 
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. More...
 
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. More...
 
bool Mark (Ptr< QueueDiscItem > item, const char *reason)
 Marks the given packet and, if successful, updates the counters associated with the given reason. More...
 
- Protected Member Functions inherited from ns3::Object
 Object (const Object &o)
 Copy an Object. More...
 
virtual void NotifyNewAggregate (void)
 Notify all Objects aggregated to this one of a new Object being aggregated. More...
 
- Protected Member Functions inherited from ns3::ObjectBase
void ConstructSelf (const AttributeConstructionList &attributes)
 Complete construction of ObjectBase; invoked by derived classes. More...
 
virtual void NotifyConstructionCompleted (void)
 Notifier called once the ObjectBase is fully constructed. More...
 

Detailed Description

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


Introspection did not find any typical Config paths.

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.


Attributes

  • MaxSize: The maximum number of packets accepted by this queue disc.

Attributes defined in parent class ns3::QueueDisc

No TraceSources are defined for this type.

TraceSources defined in parent class ns3::QueueDisc

Size of this type is 928 bytes (on a 64-bit architecture).

Definition at line 49 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 51 of file pfifo-fast-queue-disc.cc.

References NS_LOG_FUNCTION.

◆ ~PfifoFastQueueDisc()

ns3::PfifoFastQueueDisc::~PfifoFastQueueDisc ( )
virtual

Definition at line 57 of file pfifo-fast-queue-disc.cc.

References NS_LOG_FUNCTION.

Member Function Documentation

◆ CheckConfig()

bool ns3::PfifoFastQueueDisc::CheckConfig ( void  )
privatevirtual

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 143 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 ( void  )
privatevirtual

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 101 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)
privatevirtual

This function actually enqueues a packet into the queue disc.

Parameters
itemitem to enqueue
Returns
True if the operation was successful; false otherwise

Implements ns3::QueueDisc.

Definition at line 65 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 ( void  )
privatevirtual

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 122 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 ( void  )
static

Get the type ID.

Returns
the object TypeId

Definition at line 35 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 ( void  )
privatevirtual

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 196 of file pfifo-fast-queue-disc.cc.

References NS_LOG_FUNCTION.

Member Data Documentation

◆ LIMIT_EXCEEDED_DROP

constexpr const char* ns3::PfifoFastQueueDisc::LIMIT_EXCEEDED_DROP = "Queue disc limit exceeded"
static

Packet dropped due to queue disc limit exceeded.

Definition at line 66 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 73 of file pfifo-fast-queue-disc.h.

Referenced by DoEnqueue().


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