gem5  v22.0.0.2
Classes | Public Member Functions | Private Attributes | List of all members
gem5::SysBridge Class Reference

Each System object in gem5 is responsible for a set of RequestorIDs which identify different sources for memory requests within that System. More...

#include <sys_bridge.hh>

Inheritance diagram for gem5::SysBridge:
gem5::SimObject gem5::EventManager gem5::Serializable gem5::Drainable gem5::statistics::Group gem5::Named

Classes

class  BridgingPort
 
struct  PacketData
 
class  SysBridgeSenderState
 
class  SysBridgeSourcePort
 
class  SysBridgeTargetPort
 

Public Member Functions

PortgetPort (const std::string &if_name, PortID idx=InvalidPortID) override
 Get a port with a given name and index. More...
 
 SysBridge (const SysBridgeParams &p)
 
- Public Member Functions inherited from gem5::SimObject
const Paramsparams () const
 
 SimObject (const Params &p)
 
virtual ~SimObject ()
 
virtual void init ()
 init() is called after all C++ SimObjects have been created and all ports are connected. More...
 
virtual void loadState (CheckpointIn &cp)
 loadState() is called on each SimObject when restoring from a checkpoint. More...
 
virtual void initState ()
 initState() is called on each SimObject when not restoring from a checkpoint. More...
 
virtual void regProbePoints ()
 Register probe points for this object. More...
 
virtual void regProbeListeners ()
 Register probe listeners for this object. More...
 
ProbeManagergetProbeManager ()
 Get the probe manager for this object. More...
 
virtual void startup ()
 startup() is the final initialization call before simulation. More...
 
DrainState drain () override
 Provide a default implementation of the drain interface for objects that don't need draining. More...
 
virtual void memWriteback ()
 Write back dirty buffers to memory using functional writes. More...
 
virtual void memInvalidate ()
 Invalidate the contents of memory buffers. More...
 
void serialize (CheckpointOut &cp) const override
 Serialize an object. More...
 
void unserialize (CheckpointIn &cp) override
 Unserialize an object. More...
 
- Public Member Functions inherited from gem5::EventManager
EventQueueeventQueue () const
 
void schedule (Event &event, Tick when)
 
void deschedule (Event &event)
 
void reschedule (Event &event, Tick when, bool always=false)
 
void schedule (Event *event, Tick when)
 
void deschedule (Event *event)
 
void reschedule (Event *event, Tick when, bool always=false)
 
void wakeupEventQueue (Tick when=(Tick) -1)
 This function is not needed by the usual gem5 event loop but may be necessary in derived EventQueues which host gem5 on other schedulers. More...
 
void setCurTick (Tick newVal)
 
 EventManager (EventManager &em)
 Event manger manages events in the event queue. More...
 
 EventManager (EventManager *em)
 
 EventManager (EventQueue *eq)
 
- Public Member Functions inherited from gem5::Serializable
 Serializable ()
 
virtual ~Serializable ()
 
void serializeSection (CheckpointOut &cp, const char *name) const
 Serialize an object into a new section. More...
 
void serializeSection (CheckpointOut &cp, const std::string &name) const
 
void unserializeSection (CheckpointIn &cp, const char *name)
 Unserialize an a child object. More...
 
void unserializeSection (CheckpointIn &cp, const std::string &name)
 
- Public Member Functions inherited from gem5::Drainable
DrainState drainState () const
 Return the current drain state of an object. More...
 
virtual void notifyFork ()
 Notify a child process of a fork. More...
 
- Public Member Functions inherited from gem5::statistics::Group
 Group (Group *parent, const char *name=nullptr)
 Construct a new statistics group. More...
 
virtual ~Group ()
 
virtual void regStats ()
 Callback to set stat parameters. More...
 
virtual void resetStats ()
 Callback to reset stats. More...
 
virtual void preDumpStats ()
 Callback before stats are dumped. More...
 
void addStat (statistics::Info *info)
 Register a stat with this group. More...
 
const std::map< std::string, Group * > & getStatGroups () const
 Get all child groups associated with this object. More...
 
const std::vector< Info * > & getStats () const
 Get all stats associated with this object. More...
 
void addStatGroup (const char *name, Group *block)
 Add a stat block as a child of this block. More...
 
const InforesolveStat (std::string name) const
 Resolve a stat by its name within this group. More...
 
void mergeStatGroup (Group *block)
 Merge the contents (stats & children) of a block to this block. More...
 
 Group ()=delete
 
 Group (const Group &)=delete
 
Groupoperator= (const Group &)=delete
 
- Public Member Functions inherited from gem5::Named
 Named (const std::string &name_)
 
virtual ~Named ()=default
 
virtual std::string name () const
 

Private Attributes

SysBridgeSourcePort sourcePort
 
SysBridgeTargetPort targetPort
 

Additional Inherited Members

- Public Types inherited from gem5::SimObject
typedef SimObjectParams Params
 
- Static Public Member Functions inherited from gem5::SimObject
static void serializeAll (const std::string &cpt_dir)
 Create a checkpoint by serializing all SimObjects in the system. More...
 
static SimObjectfind (const char *name)
 Find the SimObject with the given name and return a pointer to it. More...
 
static void setSimObjectResolver (SimObjectResolver *resolver)
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
static SimObjectResolvergetSimObjectResolver ()
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
- Static Public Member Functions inherited from gem5::Serializable
static const std::string & currentSection ()
 Gets the fully-qualified name of the active section. More...
 
static void generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
 Generate a checkpoint file so that the serialization can be routed to it. More...
 
- Protected Member Functions inherited from gem5::Drainable
 Drainable ()
 
virtual ~Drainable ()
 
virtual void drainResume ()
 Resume execution after a successful drain. More...
 
void signalDrainDone () const
 Signal that an object is drained. More...
 
- Protected Attributes inherited from gem5::SimObject
const SimObjectParams & _params
 Cached copy of the object parameters. More...
 
- Protected Attributes inherited from gem5::EventManager
EventQueueeventq
 A pointer to this object's event queue. More...
 

Detailed Description

Each System object in gem5 is responsible for a set of RequestorIDs which identify different sources for memory requests within that System.

Each object within the memory system is responsible for requesting an ID if it needs one, and then using that ID in the requests it sends out.

When a simulation has multiple System objects within it, components registered with different Systems may be able to interact through the memory system. If an object uses a RequestorID it got from its parent System, and that ends up being handled by an object which is using a different parent, the target object may misinterpret or misattribute that ID, or if the number of IDs in the two systems are different, it might even index an array based on the requestor out of bounds.

This SysBridge object helps handle that situation by translating requests going across it in either direction, upstream or downstream, so that they always have a RequestorID which is valid in the current System. They register themselves as a Requestor in each System, and use that ID in the foreign System, restoring the original ID as the request makes its way back to its source.

Example:

One System with a CPU in it.

sys1 = System(...) sys1.cpu = CPU(...)

One System with memory in it.

sys2 = System(...) sys2.memory = Memory(...)

A SysBridge for crossing from sys1 to sys2.

sys2.sys_bridge = SysBridge( source=sys1, target=sys2, target_port=sys2.memory.port, source_port=sys1.cpu.port)

Definition at line 79 of file sys_bridge.hh.

Constructor & Destructor Documentation

◆ SysBridge()

gem5::SysBridge::SysBridge ( const SysBridgeParams &  p)

Definition at line 45 of file sys_bridge.cc.

Member Function Documentation

◆ getPort()

Port & gem5::SysBridge::getPort ( const std::string &  if_name,
PortID  idx = InvalidPortID 
)
overridevirtual

Get a port with a given name and index.

This is used at binding time and returns a reference to a protocol-agnostic port.

gem5 has a request and response port interface. All memory objects are connected together via ports. These ports provide a rigid interface between these memory objects. These ports implement three different memory system modes: timing, atomic, and functional. The most important mode is the timing mode and here timing mode is used for conducting cycle-level timing experiments. The other modes are only used in special circumstances and should not be used to conduct cycle-level timing experiments. The other modes are only used in special circumstances. These ports allow SimObjects to communicate with each other.

Parameters
if_namePort name
idxIndex in the case of a VectorPort
Returns
A reference to the given port

Reimplemented from gem5::SimObject.

Definition at line 53 of file sys_bridge.cc.

References gem5::SimObject::getPort(), sourcePort, and targetPort.

Member Data Documentation

◆ sourcePort

SysBridgeSourcePort gem5::SysBridge::sourcePort
private

Definition at line 341 of file sys_bridge.hh.

Referenced by getPort().

◆ targetPort

SysBridgeTargetPort gem5::SysBridge::targetPort
private

Definition at line 342 of file sys_bridge.hh.

Referenced by getPort().


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

Generated on Thu Jul 28 2022 13:33:14 for gem5 by doxygen 1.8.17