a calendar queue event scheduler More...
#include "calendar-scheduler.h"
Public Member Functions | |
CalendarScheduler () | |
Constructor. | |
~CalendarScheduler () override | |
Destructor. | |
void | Insert (const Scheduler::Event &ev) override |
Insert a new Event in the schedule. | |
bool | IsEmpty () const override |
Test if the schedule is empty. | |
Scheduler::Event | PeekNext () const override |
Get a pointer to the next event. | |
void | Remove (const Scheduler::Event &ev) override |
Remove a specific event from the event list. | |
Scheduler::Event | RemoveNext () override |
Remove the earliest event from the event list. | |
Public Member Functions inherited from ns3::Scheduler | |
~Scheduler () override=0 | |
Destructor. | |
virtual void | Insert (const Event &ev)=0 |
Insert a new Event in the schedule. | |
virtual bool | IsEmpty () const =0 |
Test if the schedule is empty. | |
virtual Event | PeekNext () const =0 |
Get a pointer to the next event. | |
virtual void | Remove (const Event &ev)=0 |
Remove a specific event from the event list. | |
virtual Event | RemoveNext ()=0 |
Remove the earliest event from the event list. | |
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. | |
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) 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. | |
virtual TypeId | GetInstanceTypeId () const =0 |
Get the most derived TypeId for this Object. | |
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 () |
Register this type. | |
Static Public Member Functions inherited from ns3::Scheduler | |
static TypeId | GetTypeId () |
Register this type. | |
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. | |
Private Types | |
typedef std::list< Scheduler::Event > | Bucket |
Calendar bucket type: a list of Events. | |
Private Member Functions | |
uint64_t | CalculateNewWidth () |
Compute the new bucket size, based on up to the first 25 entries. | |
void | DoInsert (const Scheduler::Event &ev) |
Insert a new event in to the correct bucket. | |
Scheduler::Event | DoRemoveNext () |
Remove the earliest event. | |
void | DoResize (uint32_t newSize, uint64_t newWidth) |
Resize the number of buckets and width. | |
uint32_t | Hash (uint64_t key) const |
Hash the dimensionless time to a bucket. | |
void | Init (uint32_t nBuckets, uint64_t width, uint64_t startPrio) |
Initialize the calendar queue. | |
void | PrintInfo () |
Print the configuration and bucket size distribution. | |
void | Resize (uint32_t newSize) |
Resize to a new number of buckets, with automatically computed width. | |
void | ResizeDown () |
Halve the number of buckets if necessary. | |
void | ResizeUp () |
Double the number of buckets if necessary. | |
void | SetReverse (bool reverse) |
Set the insertion order. | |
Private Attributes | |
Bucket * | m_buckets |
Array of buckets. | |
uint64_t | m_bucketTop |
Priority at the top of the bucket from which last event was dequeued. | |
uint32_t | m_lastBucket |
Bucket index from which the last event was dequeued. | |
uint64_t | m_lastPrio |
The priority of the last event removed. | |
uint32_t | m_nBuckets |
Number of buckets in the array. | |
uint32_t | m_qSize |
Number of events in queue. | |
bool | m_reverse = false |
Bucket ordering. | |
uint64_t | m_width |
Duration of a bucket, in dimensionless time units. | |
Scheduler::Event &(* | NextEvent )(Bucket &bucket) |
Get the next event from the bucket, according to m_reverse . | |
bool(* | Order )(const EventKey &newEvent, const EventKey &it) |
Ordering function to identify the insertion point, according to m_reverse . | |
void(* | Pop )(Bucket &) |
Pop the next event from the bucket, according to m_reverse . | |
Additional Inherited Members | |
Protected Member Functions inherited from ns3::Object | |
Object (const Object &o) | |
Copy an Object. | |
virtual void | DoDispose () |
Destructor implementation. | |
virtual void | DoInitialize () |
Initialize() implementation. | |
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 Functions inherited from ns3::ObjectBase | |
static TypeId | GetObjectIid () |
Ensure the TypeId for ObjectBase gets fully configured to anchor the inheritance tree properly. | |
a calendar queue event scheduler
Introspection did not find any typical Config paths.
This event scheduler is a direct implementation of the algorithm known as a calendar queue, first published in 1988 in "Calendar Queues: A Fast O(1) Priority Queue Implementation for the Simulation Event Set Problem" by Randy Brown. There are many refinements published later but this class implements the original algorithm (to the best of my knowledge).
This class uses a vector of buckets; each bucket covers a uniform time span. The bucket index for an event with timestamp ts
is (ts / m_width) % m_nBuckets
. This class automatically adjusts the number of buckets to keep the average occupancy around 2. Buckets themselves are implemented as a std::list<>
, and events are kept sorted within the buckets.
Operation | Amortized Time | Reason |
---|---|---|
Insert() | ~Constant | Ordering within bucket; possible resize |
IsEmpty() | Constant | Explicit queue size |
PeekNext() | ~Constant | Search buckets |
Remove() | ~Constant | Search within bucket; possible resize |
RemoveNext() | ~Constant | Search buckets; possible resize |
Category | Memory | Reason |
---|---|---|
Overhead | 2 x sizeof (*) + size_t (24 bytes) | std::list |
Per Event | 2 x sizeof (*) | std::list |
No TraceSources are defined for this type.
Size of this type is 120 bytes (on a 64-bit architecture).
Definition at line 93 of file calendar-scheduler.h.
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private |
Calendar bucket type: a list of Events.
Definition at line 169 of file calendar-scheduler.h.
ns3::CalendarScheduler::CalendarScheduler | ( | ) |
Constructor.
Definition at line 62 of file calendar-scheduler.cc.
References Init(), m_qSize, and NS_LOG_FUNCTION.
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override |
Destructor.
Definition at line 69 of file calendar-scheduler.cc.
References m_buckets, and NS_LOG_FUNCTION.
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private |
Compute the new bucket size, based on up to the first 25 entries.
Definition at line 309 of file calendar-scheduler.cc.
References DoInsert(), DoRemoveNext(), m_bucketTop, m_lastBucket, m_lastPrio, m_qSize, and NS_LOG_FUNCTION.
Referenced by Resize().
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private |
Insert a new event in to the correct bucket.
[in] | ev | The new Event. |
Definition at line 132 of file calendar-scheduler.cc.
References Hash(), ns3::Scheduler::Event::key, m_buckets, ns3::Scheduler::EventKey::m_ts, ns3::Scheduler::EventKey::m_uid, NS_LOG_FUNCTION, NS_LOG_LOGIC, and Order.
Referenced by CalculateNewWidth(), DoResize(), and Insert().
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private |
Remove the earliest event.
Definition at line 203 of file calendar-scheduler.cc.
References Hash(), IsEmpty(), ns3::Scheduler::Event::key, m_buckets, m_bucketTop, ns3::Scheduler::EventKey::m_context, m_lastBucket, m_lastPrio, m_nBuckets, ns3::Scheduler::EventKey::m_ts, ns3::Scheduler::EventKey::m_uid, m_width, NextEvent, NS_ASSERT, NS_LOG_FUNCTION, and Pop.
Referenced by CalculateNewWidth(), and RemoveNext().
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private |
Resize the number of buckets and width.
[in] | newSize | The number of buckets. |
[in] | newWidth | The size of the new buckets. |
Definition at line 388 of file calendar-scheduler.cc.
References DoInsert(), Init(), m_buckets, m_lastPrio, m_nBuckets, and NS_LOG_FUNCTION.
Referenced by Resize().
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static |
Register this type.
Definition at line 47 of file calendar-scheduler.cc.
References ns3::TypeId::ATTR_CONSTRUCT, ns3::MakeBooleanAccessor(), ns3::MakeBooleanChecker(), ns3::TypeId::SetParent(), and SetReverse().
Referenced by SimulatorTestSuite::SimulatorTestSuite().
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inlineprivate |
Hash the dimensionless time to a bucket.
[in] | key | The dimensionless time. |
Definition at line 123 of file calendar-scheduler.cc.
References m_nBuckets, m_width, and NS_LOG_FUNCTION.
Referenced by DoInsert(), DoRemoveNext(), Init(), and Remove().
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private |
Initialize the calendar queue.
[in] | nBuckets | The number of buckets. |
[in] | width | The bucket size, in dimensionless time units. |
[in] | startPrio | The starting time. |
Definition at line 97 of file calendar-scheduler.cc.
References Hash(), m_buckets, m_bucketTop, m_lastBucket, m_lastPrio, m_nBuckets, m_width, and NS_LOG_FUNCTION.
Referenced by CalendarScheduler(), and DoResize().
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overridevirtual |
Insert a new Event in the schedule.
[in] | ev | Event to store in the event list |
Implements ns3::Scheduler.
Definition at line 153 of file calendar-scheduler.cc.
References DoInsert(), m_qSize, NS_LOG_FUNCTION, and ResizeUp().
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overridevirtual |
Test if the schedule is empty.
true
if the event list is empty and false
otherwise. Implements ns3::Scheduler.
Definition at line 162 of file calendar-scheduler.cc.
References m_qSize, and NS_LOG_FUNCTION.
Referenced by DoRemoveNext(), PeekNext(), Remove(), and RemoveNext().
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overridevirtual |
Get a pointer to the next event.
This method cannot be invoked if the list is empty.
Implements ns3::Scheduler.
Definition at line 169 of file calendar-scheduler.cc.
References ns3::Scheduler::Event::impl, IsEmpty(), ns3::Scheduler::Event::key, m_buckets, m_bucketTop, ns3::Scheduler::EventKey::m_context, m_lastBucket, m_nBuckets, ns3::Scheduler::EventKey::m_ts, ns3::Scheduler::EventKey::m_uid, m_width, NextEvent, NS_ASSERT, and NS_LOG_FUNCTION.
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private |
Print the configuration and bucket size distribution.
Definition at line 109 of file calendar-scheduler.cc.
References m_buckets, m_nBuckets, m_width, and NS_LOG_FUNCTION.
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overridevirtual |
Remove a specific event from the event list.
This method cannot be invoked if the list is empty.
[in] | ev | The event to remove |
Implements ns3::Scheduler.
Definition at line 263 of file calendar-scheduler.cc.
References Hash(), ns3::Scheduler::Event::impl, IsEmpty(), ns3::Scheduler::Event::key, m_buckets, m_qSize, ns3::Scheduler::EventKey::m_ts, ns3::Scheduler::EventKey::m_uid, NS_ASSERT, NS_LOG_FUNCTION, and ResizeDown().
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overridevirtual |
Remove the earliest event from the event list.
This method cannot be invoked if the list is empty.
Implements ns3::Scheduler.
Definition at line 249 of file calendar-scheduler.cc.
References DoRemoveNext(), IsEmpty(), ns3::Scheduler::Event::key, m_bucketTop, m_lastBucket, m_qSize, ns3::Scheduler::EventKey::m_ts, ns3::Scheduler::EventKey::m_uid, NS_ASSERT, NS_LOG_FUNCTION, NS_LOG_LOGIC, and ResizeDown().
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private |
Resize to a new number of buckets, with automatically computed width.
[in] | newSize | The new number of buckets. |
Definition at line 408 of file calendar-scheduler.cc.
References CalculateNewWidth(), DoResize(), and NS_LOG_FUNCTION.
Referenced by ResizeDown(), and ResizeUp().
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private |
Halve the number of buckets if necessary.
Definition at line 298 of file calendar-scheduler.cc.
References m_nBuckets, m_qSize, NS_LOG_FUNCTION, and Resize().
Referenced by Remove(), and RemoveNext().
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private |
Double the number of buckets if necessary.
Definition at line 287 of file calendar-scheduler.cc.
References m_nBuckets, m_qSize, NS_LOG_FUNCTION, and Resize().
Referenced by Insert().
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private |
Set the insertion order.
This can only be used at construction, as invoked by the Attribute Reverse.
[in] | reverse | If true , store events in decreasing time stamp order. |
Definition at line 77 of file calendar-scheduler.cc.
References m_reverse, NextEvent, NS_LOG_FUNCTION, Order, and Pop.
Referenced by GetTypeId().
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private |
Array of buckets.
Definition at line 172 of file calendar-scheduler.h.
Referenced by ~CalendarScheduler(), DoInsert(), DoRemoveNext(), DoResize(), Init(), PeekNext(), PrintInfo(), and Remove().
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private |
Priority at the top of the bucket from which last event was dequeued.
Definition at line 180 of file calendar-scheduler.h.
Referenced by CalculateNewWidth(), DoRemoveNext(), Init(), PeekNext(), and RemoveNext().
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private |
Bucket index from which the last event was dequeued.
Definition at line 178 of file calendar-scheduler.h.
Referenced by CalculateNewWidth(), DoRemoveNext(), Init(), PeekNext(), and RemoveNext().
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private |
The priority of the last event removed.
Definition at line 182 of file calendar-scheduler.h.
Referenced by CalculateNewWidth(), DoRemoveNext(), DoResize(), and Init().
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private |
Number of buckets in the array.
Definition at line 174 of file calendar-scheduler.h.
Referenced by DoRemoveNext(), DoResize(), Hash(), Init(), PeekNext(), PrintInfo(), ResizeDown(), and ResizeUp().
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private |
Number of events in queue.
Definition at line 184 of file calendar-scheduler.h.
Referenced by CalendarScheduler(), CalculateNewWidth(), Insert(), IsEmpty(), Remove(), RemoveNext(), ResizeDown(), and ResizeUp().
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private |
Bucket ordering.
If false
(default), store events in increasing time stamp order. If true
, store events in decreasing time stamp order.
Definition at line 219 of file calendar-scheduler.h.
Referenced by SetReverse().
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private |
Duration of a bucket, in dimensionless time units.
Definition at line 176 of file calendar-scheduler.h.
Referenced by DoRemoveNext(), Hash(), Init(), PeekNext(), and PrintInfo().
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private |
Get the next event from the bucket, according to m_reverse
.
[in] | bucket | The bucket to draw from. |
bucket
. Definition at line 201 of file calendar-scheduler.h.
Referenced by DoRemoveNext(), PeekNext(), and SetReverse().
Ordering function to identify the insertion point, according to m_reverse
.
[in] | newEvent | The new event being inserted. |
[in] | it | The current position in the bucket being examined. |
true
if the newEvent
belongs before it
. Definition at line 208 of file calendar-scheduler.h.
Referenced by DoInsert(), and SetReverse().
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private |
Pop the next event from the bucket, according to m_reverse
.
[in] | bucket | The bucket to pop from. |
Definition at line 213 of file calendar-scheduler.h.
Referenced by DoRemoveNext(), and SetReverse().