gem5  v20.1.0.0
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BaseXBar Class Reference

The base crossbar contains the common elements of the non-coherent and coherent crossbar. More...

#include <xbar.hh>

Inheritance diagram for BaseXBar:
ClockedObject SimObject Clocked EventManager Serializable Drainable Stats::Group CoherentXBar NoncoherentXBar HMCController

Classes

class  Layer
 A layer is an internal crossbar arbitration point with its own flow control. More...
 
class  ReqLayer
 
class  RespLayer
 
class  SnoopRespLayer
 

Public Member Functions

virtual ~BaseXBar ()
 
PortgetPort (const std::string &if_name, PortID idx=InvalidPortID) override
 A function used to return the port associated with this object. More...
 
void regStats () override
 Callback to set stat parameters. More...
 
- Public Member Functions inherited from ClockedObject
 ClockedObject (const ClockedObjectParams *p)
 
const Paramsparams () const
 
void serialize (CheckpointOut &cp) const override
 Serialize an object. More...
 
void unserialize (CheckpointIn &cp) override
 Unserialize an object. More...
 
- Public Member Functions inherited from SimObject
const Paramsparams () const
 
 SimObject (const Params *_params)
 
virtual ~SimObject ()
 
virtual const std::string name () const
 
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 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 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 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 Stats::Group
 Group (Group *parent, const char *name=nullptr)
 Construct a new statistics group. More...
 
virtual ~Group ()
 
virtual void resetStats ()
 Callback to reset stats. More...
 
virtual void preDumpStats ()
 Callback before stats are dumped. More...
 
void addStat (Stats::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...
 
 Group ()=delete
 
 Group (const Group &)=delete
 
Groupoperator= (const Group &)=delete
 
- Public Member Functions inherited from Clocked
void updateClockPeriod ()
 Update the tick to the current tick. More...
 
Tick clockEdge (Cycles cycles=Cycles(0)) const
 Determine the tick when a cycle begins, by default the current one, but the argument also enables the caller to determine a future cycle. More...
 
Cycles curCycle () const
 Determine the current cycle, corresponding to a tick aligned to a clock edge. More...
 
Tick nextCycle () const
 Based on the clock of the object, determine the start tick of the first cycle that is at least one cycle in the future. More...
 
uint64_t frequency () const
 
Tick clockPeriod () const
 
double voltage () const
 
Cycles ticksToCycles (Tick t) const
 
Tick cyclesToTicks (Cycles c) const
 

Protected Member Functions

virtual void recvRangeChange (PortID mem_side_port_id)
 Function called by the port when the crossbar is recieving a range change. More...
 
PortID findPort (AddrRange addr_range)
 Find which port connected to this crossbar (if any) should be given a packet with this address range. More...
 
AddrRangeList getAddrRanges () const
 Return the address ranges the crossbar is responsible for. More...
 
void calcPacketTiming (PacketPtr pkt, Tick header_delay)
 Calculate the timing parameters for the packet. More...
 
 BaseXBar (const BaseXBarParams *p)
 
- Protected Member Functions inherited from 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 Member Functions inherited from Clocked
 Clocked (ClockDomain &clk_domain)
 Create a clocked object and set the clock domain based on the parameters. More...
 
 Clocked (Clocked &)=delete
 
Clockedoperator= (Clocked &)=delete
 
virtual ~Clocked ()
 Virtual destructor due to inheritance. More...
 
void resetClock () const
 Reset the object's clock using the current global tick value. More...
 
virtual void clockPeriodUpdated ()
 A hook subclasses can implement so they can do any extra work that's needed when the clock rate is changed. More...
 

Protected Attributes

const Cycles frontendLatency
 Cycles of front-end pipeline including the delay to accept the request and to decode the address. More...
 
const Cycles forwardLatency
 
const Cycles responseLatency
 
const Cycles headerLatency
 Cycles the layer is occupied processing the packet header. More...
 
const uint32_t width
 the width of the xbar in bytes More...
 
AddrRangeMap< PortID, 3 > portMap
 
std::unordered_map< RequestPtr, PortIDrouteTo
 Remember where request packets came from so that we can route responses to the appropriate port. More...
 
AddrRangeList xbarRanges
 all contigous ranges seen by this crossbar More...
 
AddrRange defaultRange
 
std::vector< bool > gotAddrRanges
 Remember for each of the memory-side ports of the crossbar if we got an address range from the connected CPU-side ports. More...
 
bool gotAllAddrRanges
 
std::vector< QueuedResponsePort * > cpuSidePorts
 The memory-side ports and CPU-side ports of the crossbar. More...
 
std::vector< RequestPort * > memSidePorts
 
PortID defaultPortID
 Port that handles requests that don't match any of the interfaces. More...
 
const bool useDefaultRange
 If true, use address range provided by default device. More...
 
Stats::Vector transDist
 Stats for transaction distribution and data passing through the crossbar. More...
 
Stats::Vector2d pktCount
 
Stats::Vector2d pktSize
 
- Protected Attributes inherited from SimObject
const SimObjectParams * _params
 Cached copy of the object parameters. More...
 
- Protected Attributes inherited from EventManager
EventQueueeventq
 A pointer to this object's event queue. More...
 

Additional Inherited Members

- Public Types inherited from ClockedObject
typedef ClockedObjectParams Params
 Parameters of ClockedObject. More...
 
- Public Types inherited from SimObject
typedef SimObjectParams Params
 
- Static Public Member Functions inherited from SimObject
static void serializeAll (CheckpointOut &cp)
 Serialize 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 Public Member Functions inherited from Serializable
static const std::string & currentSection ()
 Gets the fully-qualified name of the active section. More...
 
static void serializeAll (const std::string &cpt_dir)
 Serializes all the SimObjects. More...
 
static void unserializeGlobals (CheckpointIn &cp)
 
- Public Attributes inherited from ClockedObject
PowerStatepowerState
 

Detailed Description

The base crossbar contains the common elements of the non-coherent and coherent crossbar.

It is an abstract class that does not have any of the functionality relating to the actual reception and transmission of packets, as this is left for the subclasses.

The BaseXBar is responsible for the basic flow control (busy or not), the administration of retries, and the address decoding.

Definition at line 68 of file xbar.hh.

Constructor & Destructor Documentation

◆ BaseXBar()

BaseXBar::BaseXBar ( const BaseXBarParams *  p)
protected

Definition at line 54 of file xbar.cc.

◆ ~BaseXBar()

BaseXBar::~BaseXBar ( )
virtual

Definition at line 74 of file xbar.cc.

References cpuSidePorts, and memSidePorts.

Member Function Documentation

◆ calcPacketTiming()

void BaseXBar::calcPacketTiming ( PacketPtr  pkt,
Tick  header_delay 
)
protected

Calculate the timing parameters for the packet.

Updates the headerDelay and payloadDelay fields of the packet object with the relative number of ticks required to transmit the header and the payload, respectively.

Parameters
pktPacket to populate with timings
header_delayHeader delay to be added

Definition at line 101 of file xbar.cc.

References Clocked::clockEdge(), Clocked::clockPeriod(), curTick(), divCeil(), Packet::getSize(), Packet::hasData(), Packet::headerDelay, ArmISA::offset, panic_if, Packet::payloadDelay, SimClock::Int::us, and width.

Referenced by HMCController::recvTimingReq(), NoncoherentXBar::recvTimingReq(), CoherentXBar::recvTimingReq(), NoncoherentXBar::recvTimingResp(), CoherentXBar::recvTimingResp(), CoherentXBar::recvTimingSnoopReq(), and CoherentXBar::recvTimingSnoopResp().

◆ findPort()

PortID BaseXBar::findPort ( AddrRange  addr_range)
protected

◆ getAddrRanges()

AddrRangeList BaseXBar::getAddrRanges ( ) const
protected

Return the address ranges the crossbar is responsible for.

Returns
a list of non-overlapping address ranges

Definition at line 522 of file xbar.cc.

References DPRINTF, gotAllAddrRanges, and xbarRanges.

Referenced by NoncoherentXBar::NoncoherentXBarResponsePort::getAddrRanges(), CoherentXBar::CoherentXBarResponsePort::getAddrRanges(), and recvRangeChange().

◆ getPort()

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

A function used to return the port associated with this object.

Reimplemented from SimObject.

Definition at line 84 of file xbar.cc.

References cpuSidePorts, defaultPortID, SimObject::getPort(), and memSidePorts.

◆ recvRangeChange()

void BaseXBar::recvRangeChange ( PortID  mem_side_port_id)
protectedvirtual

◆ regStats()

void BaseXBar::regStats ( )
overridevirtual

Callback to set stat parameters.

This callback is typically used for complex stats (e.g., distributions) that need parameters in addition to a name and a description. Stat names and descriptions should typically be set from the constructor usingo from the constructor using the ADD_STAT macro.

Reimplemented from Stats::Group.

Definition at line 540 of file xbar.cc.

References cpuSidePorts, Stats::DataWrap< Derived, InfoProxyType >::flags(), ArmISA::i, Stats::VectorBase< Derived, Stor >::init(), Stats::Vector2dBase< Derived, Stor >::init(), ArmISA::j, memSidePorts, SimObject::name(), Stats::nonan, Stats::nozero, MemCmd::NUM_MEM_CMDS, pktCount, pktSize, Stats::Group::regStats(), Stats::DataWrapVec< Derived, InfoProxyType >::subname(), MemCmd::toString(), Stats::total, transDist, and Stats::DataWrapVec2d< Derived, InfoProxyType >::ysubname().

Referenced by CoherentXBar::regStats().

Member Data Documentation

◆ cpuSidePorts

std::vector<QueuedResponsePort*> BaseXBar::cpuSidePorts
protected

◆ defaultPortID

PortID BaseXBar::defaultPortID
protected

Port that handles requests that don't match any of the interfaces.

Definition at line 380 of file xbar.hh.

Referenced by CoherentXBar::CoherentXBar(), findPort(), getPort(), NoncoherentXBar::NoncoherentXBar(), and recvRangeChange().

◆ defaultRange

AddrRange BaseXBar::defaultRange
protected

Definition at line 329 of file xbar.hh.

Referenced by findPort(), and recvRangeChange().

◆ forwardLatency

const Cycles BaseXBar::forwardLatency
protected

◆ frontendLatency

const Cycles BaseXBar::frontendLatency
protected

Cycles of front-end pipeline including the delay to accept the request and to decode the address.

Definition at line 308 of file xbar.hh.

Referenced by HMCController::recvTimingReq(), NoncoherentXBar::recvTimingReq(), and CoherentXBar::recvTimingReq().

◆ gotAddrRanges

std::vector<bool> BaseXBar::gotAddrRanges
protected

Remember for each of the memory-side ports of the crossbar if we got an address range from the connected CPU-side ports.

For convenience, also keep track of if we got ranges from all the CPU-side-port modules or not.

Definition at line 372 of file xbar.hh.

Referenced by HMCController::recvRangeChange(), and recvRangeChange().

◆ gotAllAddrRanges

bool BaseXBar::gotAllAddrRanges
protected

Definition at line 373 of file xbar.hh.

Referenced by findPort(), getAddrRanges(), HMCController::recvRangeChange(), and recvRangeChange().

◆ headerLatency

const Cycles BaseXBar::headerLatency
protected

Cycles the layer is occupied processing the packet header.

Definition at line 312 of file xbar.hh.

Referenced by CoherentXBar::recvTimingReq(), CoherentXBar::recvTimingResp(), and CoherentXBar::recvTimingSnoopResp().

◆ memSidePorts

std::vector<RequestPort*> BaseXBar::memSidePorts
protected

◆ pktCount

Stats::Vector2d BaseXBar::pktCount
protected

◆ pktSize

Stats::Vector2d BaseXBar::pktSize
protected

◆ portMap

AddrRangeMap<PortID, 3> BaseXBar::portMap
protected

Definition at line 316 of file xbar.hh.

Referenced by findPort(), and recvRangeChange().

◆ responseLatency

const Cycles BaseXBar::responseLatency
protected

◆ routeTo

std::unordered_map<RequestPtr, PortID> BaseXBar::routeTo
protected

Remember where request packets came from so that we can route responses to the appropriate port.

This relies on the fact that the underlying Request pointer inside the Packet stays constant.

Definition at line 324 of file xbar.hh.

Referenced by HMCController::recvTimingReq(), NoncoherentXBar::recvTimingReq(), CoherentXBar::recvTimingReq(), NoncoherentXBar::recvTimingResp(), CoherentXBar::recvTimingResp(), CoherentXBar::recvTimingSnoopReq(), and CoherentXBar::recvTimingSnoopResp().

◆ transDist

Stats::Vector BaseXBar::transDist
protected

Stats for transaction distribution and data passing through the crossbar.

The transaction distribution is globally counting different types of commands. The packet count and total packet size are two-dimensional vectors that are indexed by the CPU-side port and memory-side port id (thus the neighbouring memory-side ports and neighbouring CPU-side ports), summing up both directions (request and response).

Definition at line 399 of file xbar.hh.

Referenced by NoncoherentXBar::recvAtomicBackdoor(), CoherentXBar::recvAtomicBackdoor(), HMCController::recvTimingReq(), NoncoherentXBar::recvTimingReq(), CoherentXBar::recvTimingReq(), NoncoherentXBar::recvTimingResp(), CoherentXBar::recvTimingResp(), CoherentXBar::recvTimingSnoopReq(), CoherentXBar::recvTimingSnoopResp(), and regStats().

◆ useDefaultRange

const bool BaseXBar::useDefaultRange
protected

If true, use address range provided by default device.

Any address not handled by another port and not in default device's range will cause a fatal error. If false, just send all addresses not handled by another port to default device.

Definition at line 386 of file xbar.hh.

Referenced by findPort(), and recvRangeChange().

◆ width

const uint32_t BaseXBar::width
protected

the width of the xbar in bytes

Definition at line 314 of file xbar.hh.

Referenced by calcPacketTiming().

◆ xbarRanges

AddrRangeList BaseXBar::xbarRanges
protected

all contigous ranges seen by this crossbar

Definition at line 327 of file xbar.hh.

Referenced by getAddrRanges(), and recvRangeChange().


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

Generated on Wed Sep 30 2020 14:02:22 for gem5 by doxygen 1.8.17