Maintain the event list. More...
#include "scheduler.h"
Classes | |
struct | Event |
Scheduler event. More... | |
struct | EventKey |
Structure for sorting and comparing Events. More... | |
Public Member Functions | |
~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::Object | |
static TypeId | GetTypeId () |
Register this type. | |
Static Public Member Functions inherited from ns3::ObjectBase | |
static TypeId | GetTypeId () |
Get the type ID. | |
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. | |
Maintain the event list.
Introspection did not find any typical Config paths.
In ns-3 the Scheduler manages the future event list. There are several different Scheduler implementations with different time and space tradeoffs. Which one is "best" depends in part on the characteristics of the model being executed. For optimized production work common practice is to benchmark each Scheduler on the model of interest. The utility program utils/bench-scheduler.cc can do simple benchmarking of each SchedulerImpl against an exponential or user-provided event time distribution.
The most important Scheduler functions for time performance are (usually) Scheduler::Insert (for new events) and Scheduler::RemoveNext (for pulling off the next event to execute). Simulator::Cancel is usually implemented by simply setting a bit on the Event, but leaving it in the Scheduler; the Simulator just skips those events as they are encountered.
For models which need a large event list the Scheduler overhead and per-event memory cost could also be important. Some models rely heavily on Scheduler::Cancel, however, and these might benefit from using Scheduler::Remove instead, to reduce the size of the event list, at the time cost of actually removing events from the list.
A summary of the main characteristics of each SchedulerImpl is provided below. See the individual Scheduler pages for details on the complexity of the other API calls. (Memory overheads assume pointers and std::size_t
are both 8 bytes.)
Scheduler Type | Complexity | ||||
---|---|---|---|---|---|
SchedulerImpl | Method | Time | Space | ||
Insert() | RemoveNext() | Overhead | Per Event | ||
CalendarScheduler | <std::list> [] | Constant | Constant | 24 bytes | 16 bytes |
HeapScheduler | Heap on std::vector | Logarithmic | Logarithmic | 24 bytes | 0 |
ListScheduler | std::list | Linear | Constant | 24 bytes | 16 bytes |
MapScheduler | std::map | Logarithmic | Constant | 40 bytes | 32 bytes |
PriorityQueueScheduler | std::priority_queue<,std::vector> | Logarithmic | Logarithmic | 24 bytes | 0 |
It is possible to change the Scheduler choice during a simulation, via Simulator::SetScheduler.
The Scheduler base class specifies the interface used to maintain the event list. If you want to provide a new event list scheduler, you need to create a subclass of this base class and implement all the pure virtual methods defined here.
The only tricky aspect of this API is the memory management of the EventImpl pointer which is a member of the Event data structure. The lifetime of this pointer is assumed to always be longer than the lifetime of the Scheduler class which means that the caller is responsible for ensuring that this invariant holds through calling EventId::Ref and SimpleRefCount::Unref at the right time. Typically, EventId::Ref is called before Insert and SimpleRefCount::Unref is called after a call to one of the Remove methods.
No Attributes are defined for this type.
No TraceSources are defined for this type.
Size of this type is 32 bytes (on a 64-bit architecture).
Definition at line 156 of file scheduler.h.
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overridepure virtual |
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static |
Register this type.
Definition at line 44 of file scheduler.cc.
References ns3::TypeId::SetParent().
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pure virtual |
Insert a new Event in the schedule.
[in] | ev | Event to store in the event list |
Implemented in ns3::CalendarScheduler, ns3::HeapScheduler, ns3::ListScheduler, ns3::MapScheduler, and ns3::PriorityQueueScheduler.
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pure virtual |
Test if the schedule is empty.
true
if the event list is empty and false
otherwise. Implemented in ns3::CalendarScheduler, ns3::HeapScheduler, ns3::ListScheduler, ns3::MapScheduler, and ns3::PriorityQueueScheduler.
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pure virtual |
Get a pointer to the next event.
This method cannot be invoked if the list is empty.
Implemented in ns3::CalendarScheduler, ns3::HeapScheduler, ns3::ListScheduler, ns3::MapScheduler, and ns3::PriorityQueueScheduler.
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pure virtual |
Remove a specific event from the event list.
This method cannot be invoked if the list is empty.
[in] | ev | The event to remove |
Implemented in ns3::CalendarScheduler, ns3::HeapScheduler, ns3::ListScheduler, ns3::MapScheduler, and ns3::PriorityQueueScheduler.
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pure virtual |
Remove the earliest event from the event list.
This method cannot be invoked if the list is empty.
Implemented in ns3::CalendarScheduler, ns3::HeapScheduler, ns3::ListScheduler, ns3::MapScheduler, and ns3::PriorityQueueScheduler.