A coherent crossbar connects a number of (potentially) snooping requestors and responders, and routes the request and response packets based on the address, and also forwards all requests to the snoopers and deals with the snoop responses. More...

#include <coherent_xbar.hh>

Inheritance diagram for gem5::CoherentXBar:

Classes
class	CoherentXBarRequestPort
	Declaration of the coherent crossbar memory-side port type, one will be instantiated for each of the CPU-side-port interfaces connecting to the crossbar. More...

class	CoherentXBarResponsePort
	Declaration of the coherent crossbar CPU-side port type, one will be instantiated for each of the mem_side_ports connecting to the crossbar. More...

class	SnoopRespPort
	Internal class to bridge between an incoming snoop response from a CPU-side port and forwarding it through an outgoing CPU-side port. More...

Public Member Functions
virtual void	init ()
	init() is called after all C++ SimObjects have been created and all ports are connected.

	CoherentXBar (const CoherentXBarParams &p)

virtual	~CoherentXBar ()

virtual void	regStats ()
	Callback to set stat parameters.

Public Member Functions inherited from gem5::BaseXBar
virtual	~BaseXBar ()

Port &	getPort (const std::string &if_name, PortID idx=InvalidPortID) override
	A function used to return the port associated with this object.

Public Member Functions inherited from gem5::ClockedObject
	ClockedObject (const ClockedObjectParams &p)

void	serialize (CheckpointOut &cp) const override
	Serialize an object.

void	unserialize (CheckpointIn &cp) override
	Unserialize an object.

Public Member Functions inherited from gem5::SimObject
const Params &	params () const

	SimObject (const Params &p)

virtual	~SimObject ()

virtual void	loadState (CheckpointIn &cp)
	loadState() is called on each SimObject when restoring from a checkpoint.

virtual void	initState ()
	initState() is called on each SimObject when not restoring from a checkpoint.

virtual void	regProbePoints ()
	Register probe points for this object.

virtual void	regProbeListeners ()
	Register probe listeners for this object.

ProbeManager *	getProbeManager ()
	Get the probe manager for this object.

virtual void	startup ()
	startup() is the final initialization call before simulation.

DrainState	drain () override
	Provide a default implementation of the drain interface for objects that don't need draining.

virtual void	memWriteback ()
	Write back dirty buffers to memory using functional writes.

virtual void	memInvalidate ()
	Invalidate the contents of memory buffers.

void	serialize (CheckpointOut &cp) const override
	Serialize an object.

void	unserialize (CheckpointIn &cp) override
	Unserialize an object.

Public Member Functions inherited from gem5::EventManager
EventQueue *	eventQueue () 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.

void	setCurTick (Tick newVal)

	EventManager (EventManager &em)
	Event manger manages events in the event queue.

	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.

void	serializeSection (CheckpointOut &cp, const std::string &name) const

void	unserializeSection (CheckpointIn &cp, const char *name)
	Unserialize an a child object.

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.

virtual void	notifyFork ()
	Notify a child process of a fork.

Public Member Functions inherited from gem5::statistics::Group
	Group (Group parent, const char name=nullptr)
	Construct a new statistics group.

virtual	~Group ()

virtual void	resetStats ()
	Callback to reset stats.

virtual void	preDumpStats ()
	Callback before stats are dumped.

void	addStat (statistics::Info *info)
	Register a stat with this group.

const std::map< std::string, Group * > &	getStatGroups () const
	Get all child groups associated with this object.

const std::vector< Info * > &	getStats () const
	Get all stats associated with this object.

void	addStatGroup (const char name, Group block)
	Add a stat block as a child of this block.

const Info *	resolveStat (std::string name) const
	Resolve a stat by its name within this group.

void	mergeStatGroup (Group *block)
	Merge the contents (stats & children) of a block to this block.

	Group ()=delete

	Group (const Group &)=delete

Group &	operator= (const Group &)=delete

Public Member Functions inherited from gem5::Named
	Named (const std::string &name_)

virtual	~Named ()=default

virtual std::string	name () const

Public Member Functions inherited from gem5::Clocked
void	updateClockPeriod ()
	Update the tick to the current tick.

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.

Cycles	curCycle () const
	Determine the current cycle, corresponding to a tick aligned to a clock edge.

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.

uint64_t	frequency () const

Tick	clockPeriod () const

double	voltage () const

Cycles	ticksToCycles (Tick t) const

Tick	cyclesToTicks (Cycles c) const

Protected Member Functions
bool	recvTimingReq (PacketPtr pkt, PortID cpu_side_port_id)

bool	recvTimingResp (PacketPtr pkt, PortID mem_side_port_id)

void	recvTimingSnoopReq (PacketPtr pkt, PortID mem_side_port_id)

bool	recvTimingSnoopResp (PacketPtr pkt, PortID cpu_side_port_id)

void	recvReqRetry (PortID mem_side_port_id)

void	forwardTiming (PacketPtr pkt, PortID exclude_cpu_side_port_id)
	Forward a timing packet to our snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

void	forwardTiming (PacketPtr pkt, PortID exclude_cpu_side_port_id, const std::vector< QueuedResponsePort * > &dests)
	Forward a timing packet to a selected list of snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

Tick	recvAtomicBackdoor (PacketPtr pkt, PortID cpu_side_port_id, MemBackdoorPtr *backdoor=nullptr)

Tick	recvAtomicSnoop (PacketPtr pkt, PortID mem_side_port_id)

std::pair< MemCmd, Tick >	forwardAtomic (PacketPtr pkt, PortID exclude_cpu_side_port_id)
	Forward an atomic packet to our snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

std::pair< MemCmd, Tick >	forwardAtomic (PacketPtr pkt, PortID exclude_cpu_side_port_id, PortID source_mem_side_port_id, const std::vector< QueuedResponsePort * > &dests)
	Forward an atomic packet to a selected list of snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

void	recvFunctional (PacketPtr pkt, PortID cpu_side_port_id)
	Function called by the port when the crossbar is receiving a Functional transaction.

void	recvMemBackdoorReq (const MemBackdoorReq &req, MemBackdoorPtr &backdoor)
	Function called by the port when the crossbar receives a request for a memory backdoor.

void	recvFunctionalSnoop (PacketPtr pkt, PortID mem_side_port_id)
	Function called by the port when the crossbar is receiving a functional snoop transaction.

void	forwardFunctional (PacketPtr pkt, PortID exclude_cpu_side_port_id)
	Forward a functional packet to our snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

bool	sinkPacket (const PacketPtr pkt) const
	Determine if the crossbar should sink the packet, as opposed to forwarding it, or responding.

bool	forwardPacket (const PacketPtr pkt)
	Determine if the crossbar should forward the packet, as opposed to responding to it.

bool	isDestination (const PacketPtr pkt) const
	Determine if the packet's destination is the memory below.

Protected Member Functions inherited from gem5::BaseXBar
virtual void	recvRangeChange (PortID mem_side_port_id)
	Function called by the port when the crossbar is recieving a range change.

PortID	findPort (AddrRange addr_range, PacketPtr pkt=nullptr)
	Find which port connected to this crossbar (if any) should be given a packet with this address range.

PortID	findPort (PacketPtr pkt)

AddrRangeList	getAddrRanges () const
	Return the address ranges the crossbar is responsible for.

void	calcPacketTiming (PacketPtr pkt, Tick header_delay)
	Calculate the timing parameters for the packet.

	BaseXBar (const BaseXBarParams &p)

Protected Member Functions inherited from gem5::Drainable
	Drainable ()

virtual	~Drainable ()

virtual void	drainResume ()
	Resume execution after a successful drain.

void	signalDrainDone () const
	Signal that an object is drained.

Protected Member Functions inherited from gem5::Clocked
	Clocked (ClockDomain &clk_domain)
	Create a clocked object and set the clock domain based on the parameters.

	Clocked (Clocked &)=delete

Clocked &	operator= (Clocked &)=delete

virtual	~Clocked ()
	Virtual destructor due to inheritance.

void	resetClock () const
	Reset the object's clock using the current global tick value.

virtual void	clockPeriodUpdated ()
	A hook subclasses can implement so they can do any extra work that's needed when the clock rate is changed.

Protected Attributes
std::vector< ReqLayer * >	reqLayers
	Declare the layers of this crossbar, one vector for requests, one for responses, and one for snoop responses.

std::vector< RespLayer * >	respLayers

std::vector< SnoopRespLayer * >	snoopLayers

std::vector< SnoopRespPort * >	snoopRespPorts

std::vector< QueuedResponsePort * >	snoopPorts

std::unordered_set< RequestPtr >	outstandingSnoop
	Store the outstanding requests that we are expecting snoop responses from so we can determine which snoop responses we generated and which ones were merely forwarded.

std::unordered_map< PacketId, PacketPtr >	outstandingCMO
	Store the outstanding cache maintenance that we are expecting snoop responses from so we can determine when we received all snoop responses and if any of the agents satisfied the request.

System *	system
	Keep a pointer to the system to be allow to querying memory system properties.

SnoopFilter *	snoopFilter
	A snoop filter that tracks cache line residency and can restrict the broadcast needed for probes.

const Cycles	snoopResponseLatency
	Cycles of snoop response latency.

const unsigned int	maxOutstandingSnoopCheck
	Maximum number of outstading snoops sanity check.

const unsigned int	maxRoutingTableSizeCheck
	Maximum routing table size sanity check.

const bool	pointOfCoherency
	Is this crossbar the point of coherency?

const bool	pointOfUnification
	Is this crossbar the point of unification?

std::unique_ptr< Packet >	pendingDelete
	Upstream caches need this packet until true is returned, so hold it for deletion until a subsequent call.

statistics::Scalar	snoops

statistics::Scalar	snoopTraffic

statistics::Distribution	snoopFanout

Protected Attributes inherited from gem5::BaseXBar
const Cycles	frontendLatency
	Cycles of front-end pipeline including the delay to accept the request and to decode the address.

const Cycles	forwardLatency

const Cycles	responseLatency

const Cycles	headerLatency
	Cycles the layer is occupied processing the packet header.

const uint32_t	width
	the width of the xbar in bytes

AddrRangeMap< PortID, 3 >	portMap

std::unordered_map< RequestPtr, PortID >	routeTo
	Remember where request packets came from so that we can route responses to the appropriate port.

AddrRangeList	xbarRanges
	all contigous ranges seen by this crossbar

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.

bool	gotAllAddrRanges

std::vector< QueuedResponsePort * >	cpuSidePorts
	The memory-side ports and CPU-side ports of the crossbar.

std::vector< RequestPort * >	memSidePorts

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

const bool	useDefaultRange
	If true, use address range provided by default device.

statistics::Vector	transDist
	Stats for transaction distribution and data passing through the crossbar.

statistics::Vector2d	pktCount

statistics::Vector2d	pktSize

Protected Attributes inherited from gem5::SimObject
const SimObjectParams &	_params
	Cached copy of the object parameters.

Protected Attributes inherited from gem5::EventManager
EventQueue *	eventq
	A pointer to this object's event queue.

Additional Inherited Members
Public Types inherited from gem5::ClockedObject
using	Params = ClockedObjectParams
	Parameters of ClockedObject.

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.

static SimObject *	find (const char *name)
	Find the SimObject with the given name and return a pointer to it.

static void	setSimObjectResolver (SimObjectResolver *resolver)
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.

static SimObjectResolver *	getSimObjectResolver ()
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.

Static Public Member Functions inherited from gem5::Serializable
static const std::string &	currentSection ()
	Gets the fully-qualified name of the active section.

static void	generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
	Generate a checkpoint file so that the serialization can be routed to it.

Public Attributes inherited from gem5::ClockedObject
PowerState *	powerState

Detailed Description

A coherent crossbar connects a number of (potentially) snooping requestors and responders, and routes the request and response packets based on the address, and also forwards all requests to the snoopers and deals with the snoop responses.

The coherent crossbar can be used as a template for modelling QPI, HyperTransport, ACE and coherent OCP buses, and is typically used for the L1-to-L2 buses and as the main system interconnect.

See also: gem5 Memory System

Definition at line 70 of file coherent_xbar.hh.

Constructor & Destructor Documentation

◆ CoherentXBar()

gem5::CoherentXBar::CoherentXBar ( const CoherentXBarParams & p )

Definition at line 58 of file coherent_xbar.cc.

References gem5::BaseXBar::cpuSidePorts, gem5::csprintf(), gem5::BaseXBar::defaultPortID, gem5::ArmISA::i, gem5::BaseXBar::memSidePorts, gem5::Named::name(), gem5::MipsISA::p, reqLayers, respLayers, snoopLayers, and snoopRespPorts.

◆ ~CoherentXBar()

gem5::CoherentXBar::~CoherentXBar ( )

virtual

Definition at line 111 of file coherent_xbar.cc.

References gem5::MipsISA::l, gem5::MipsISA::p, reqLayers, respLayers, snoopLayers, and snoopRespPorts.

Member Function Documentation

◆ forwardAtomic() [1/2]

std::pair< MemCmd, Tick > gem5::CoherentXBar::forwardAtomic	(	PacketPtr	pkt,
		PortID	exclude_cpu_side_port_id )

inlineprotected

Forward an atomic packet to our snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

Parameters

pkt	Packet to forward
exclude_cpu_side_port_id	Id of CPU-side port to exclude

Returns: a pair containing the snoop response and snoop latency

Definition at line 355 of file coherent_xbar.hh.

References forwardAtomic(), gem5::InvalidPortID, and snoopPorts.

Referenced by forwardAtomic(), recvAtomicBackdoor(), and recvAtomicSnoop().

◆ forwardAtomic() [2/2]

std::pair< MemCmd, Tick > gem5::CoherentXBar::forwardAtomic	(	PacketPtr	pkt,
		PortID	exclude_cpu_side_port_id,
		PortID	source_mem_side_port_id,
		const std::vector< QueuedResponsePort * > &	dests )

protected

Forward an atomic packet to a selected list of snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

Parameters

pkt	Packet to forward
exclude_cpu_side_port_id	Id of CPU-side port to exclude
source_mem_side_port_id	Id of the memory-side port for snoops from below
dests	Vector of destination ports for the forwarded pkt

Returns: a pair containing the snoop response and snoop latency

Definition at line 930 of file coherent_xbar.cc.

References gem5::System::bypassCaches(), gem5::Packet::cacheResponding(), gem5::Packet::cmd, gem5::BaseXBar::cpuSidePorts, gem5::MemCmd::InvalidCmd, gem5::InvalidPortID, gem5::Packet::isResponse(), gem5::BaseXBar::memSidePorts, gem5::MipsISA::p, gem5::statistics::DistBase< Derived, Stor >::sample(), snoopFanout, snoopFilter, system, gem5::SnoopFilter::updateSnoopForward(), and gem5::SnoopFilter::updateSnoopResponse().

◆ forwardFunctional()

void gem5::CoherentXBar::forwardFunctional	(	PacketPtr	pkt,
		PortID	exclude_cpu_side_port_id )

protected

Forward a functional packet to our snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

Parameters

pkt	Packet to forward
exclude_cpu_side_port_id	Id of CPU-side port to exclude

Definition at line 1066 of file coherent_xbar.cc.

References gem5::System::bypassCaches(), gem5::InvalidPortID, gem5::Packet::isResponse(), gem5::MipsISA::p, snoopPorts, and system.

Referenced by recvFunctional(), and recvFunctionalSnoop().

◆ forwardPacket()

bool gem5::CoherentXBar::forwardPacket ( const PacketPtr pkt )

protected

Determine if the crossbar should forward the packet, as opposed to responding to it.

Definition at line 1112 of file coherent_xbar.cc.

References gem5::Packet::isClean(), isDestination(), gem5::Packet::isRead(), gem5::Packet::isWrite(), and pointOfCoherency.

Referenced by recvAtomicBackdoor(), and recvTimingReq().

◆ forwardTiming() [1/2]

void gem5::CoherentXBar::forwardTiming	(	PacketPtr	pkt,
		PortID	exclude_cpu_side_port_id )

inlineprotected

Forward a timing packet to our snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

Parameters

pkt	Packet to forward
exclude_cpu_side_port_id	Id of CPU-side port to exclude

Definition at line 323 of file coherent_xbar.hh.

References forwardTiming(), and snoopPorts.

Referenced by forwardTiming(), recvTimingReq(), and recvTimingSnoopReq().

◆ forwardTiming() [2/2]

void gem5::CoherentXBar::forwardTiming	(	PacketPtr	pkt,
		PortID	exclude_cpu_side_port_id,
		const std::vector< QueuedResponsePort * > &	dests )

protected

Forward a timing packet to a selected list of snoopers, potentially excluding one of the connected coherent requestors to avoid sending a packet back to where it came from.

Parameters

pkt	Packet to forward
exclude_cpu_side_port_id	Id of CPU-side port to exclude
dests	Vector of destination ports for the forwarded pkt

Definition at line 700 of file coherent_xbar.cc.

References gem5::System::bypassCaches(), DPRINTF, gem5::InvalidPortID, gem5::MipsISA::p, gem5::Packet::print(), gem5::statistics::DistBase< Derived, Stor >::sample(), snoopFanout, and system.

◆ init()

void gem5::CoherentXBar::init ( )

virtual

init() is called after all C++ SimObjects have been created and all ports are connected.

Initializations that are independent of unserialization but rely on a fully instantiated and connected SimObject graph should be done here.

Reimplemented from gem5::SimObject.

Definition at line 124 of file coherent_xbar.cc.

References gem5::BaseXBar::cpuSidePorts, DPRINTF, gem5::SimObject::init(), gem5::Named::name(), gem5::MipsISA::p, gem5::SnoopFilter::setCPUSidePorts(), snoopFilter, snoopPorts, and warn.

◆ isDestination()

bool gem5::CoherentXBar::isDestination ( const PacketPtr pkt ) const

inlineprotected

Determine if the packet's destination is the memory below.

The memory below is the destination for a cache mainteance operation to the Point of Coherence/Unification if this is the Point of Coherence/Unification.

Parameters

pkt	The processed packet

Returns: Whether the memory below is the destination for the packet

Definition at line 427 of file coherent_xbar.hh.

References pointOfCoherency, pointOfUnification, and gem5::Packet::req.

Referenced by forwardPacket(), recvAtomicBackdoor(), and recvTimingReq().

◆ recvAtomicBackdoor()

Tick gem5::CoherentXBar::recvAtomicBackdoor	(	PacketPtr	pkt,
		PortID	cpu_side_port_id,
		MemBackdoorPtr *	backdoor = nullptr )

protected

Definition at line 737 of file coherent_xbar.cc.

References gem5::System::bypassCaches(), gem5::Packet::clearWriteThrough(), gem5::Clocked::clockPeriod(), gem5::Packet::cmd, gem5::Packet::cmdToIndex(), gem5::BaseXBar::cpuSidePorts, DPRINTF, gem5::BaseXBar::findPort(), gem5::SnoopFilter::finishRequest(), forwardAtomic(), forwardPacket(), gem5::Packet::getAddr(), gem5::Packet::getSize(), gem5::Packet::hasData(), gem5::Packet::id, gem5::MemCmd::InvalidCmd, gem5::InvalidPortID, gem5::Packet::isClean(), isDestination(), gem5::Packet::isEviction(), gem5::Packet::isResponse(), gem5::Packet::isSecure(), gem5::Packet::isWrite(), gem5::SnoopFilter::lookupRequest(), gem5::Packet::makeResponse(), gem5::BaseXBar::memSidePorts, gem5::Named::name(), gem5::Packet::needsResponse(), outstandingCMO, gem5::Packet::payloadDelay, gem5::BaseXBar::pktCount, gem5::BaseXBar::pktSize, gem5::Packet::print(), gem5::Packet::satisfied(), gem5::Packet::setBlockCached(), sinkPacket(), snoopFilter, system, gem5::BaseXBar::transDist, gem5::SnoopFilter::updateResponse(), and gem5::MemCmd::WriteClean.

Referenced by gem5::CoherentXBar::CoherentXBarResponsePort::recvAtomic(), and gem5::CoherentXBar::CoherentXBarResponsePort::recvAtomicBackdoor().

◆ recvAtomicSnoop()

Tick gem5::CoherentXBar::recvAtomicSnoop	(	PacketPtr	pkt,
		PortID	mem_side_port_id )

protected

◆ recvFunctional()

void gem5::CoherentXBar::recvFunctional	(	PacketPtr	pkt,
		PortID	cpu_side_port_id )

protected

Function called by the port when the crossbar is receiving a Functional transaction.

Definition at line 1009 of file coherent_xbar.cc.

References gem5::System::bypassCaches(), gem5::BaseXBar::cpuSidePorts, DPRINTF, gem5::BaseXBar::findPort(), forwardFunctional(), gem5::Packet::isPrint(), gem5::Packet::isResponse(), gem5::Packet::makeResponse(), gem5::BaseXBar::memSidePorts, gem5::Named::name(), gem5::Packet::needsResponse(), gem5::MipsISA::p, gem5::Packet::print(), and system.

Referenced by gem5::CoherentXBar::CoherentXBarResponsePort::recvFunctional().

◆ recvFunctionalSnoop()

void gem5::CoherentXBar::recvFunctionalSnoop	(	PacketPtr	pkt,
		PortID	mem_side_port_id )

protected

Function called by the port when the crossbar is receiving a functional snoop transaction.

Definition at line 1045 of file coherent_xbar.cc.

References gem5::BaseXBar::cpuSidePorts, DPRINTF, forwardFunctional(), gem5::InvalidPortID, gem5::Packet::isPrint(), gem5::Packet::makeResponse(), gem5::BaseXBar::memSidePorts, gem5::Named::name(), gem5::Packet::needsResponse(), gem5::MipsISA::p, and gem5::Packet::print().

Referenced by gem5::CoherentXBar::CoherentXBarRequestPort::recvFunctionalSnoop().

◆ recvMemBackdoorReq()

void gem5::CoherentXBar::recvMemBackdoorReq	(	const MemBackdoorReq &	req,
		MemBackdoorPtr &	backdoor )

protected

Function called by the port when the crossbar receives a request for a memory backdoor.

Definition at line 1001 of file coherent_xbar.cc.

References gem5::BaseXBar::findPort(), gem5::BaseXBar::memSidePorts, and gem5::MemBackdoorReq::range().

Referenced by gem5::CoherentXBar::CoherentXBarResponsePort::recvMemBackdoorReq().

◆ recvReqRetry()

void gem5::CoherentXBar::recvReqRetry ( PortID mem_side_port_id )

protected

Definition at line 728 of file coherent_xbar.cc.

References reqLayers.

Referenced by gem5::CoherentXBar::CoherentXBarRequestPort::recvReqRetry().

◆ recvTimingReq()

bool gem5::CoherentXBar::recvTimingReq	(	PacketPtr	pkt,
		PortID	cpu_side_port_id )

protected

Definition at line 149 of file coherent_xbar.cc.

References gem5::X86ISA::addr, gem5::System::bypassCaches(), gem5::Packet::cacheResponding(), gem5::BaseXBar::calcPacketTiming(), gem5::Packet::clearWriteThrough(), gem5::Clocked::clockEdge(), gem5::Clocked::clockPeriod(), gem5::Packet::cmd, gem5::Packet::cmdToIndex(), gem5::BaseXBar::cpuSidePorts, DPRINTF, gem5::BaseXBar::findPort(), gem5::SnoopFilter::finishRequest(), gem5::BaseXBar::forwardLatency, forwardPacket(), forwardTiming(), gem5::BaseXBar::frontendLatency, gem5::Packet::getAddr(), gem5::Packet::getSize(), gem5::Packet::hasData(), gem5::Packet::headerDelay, gem5::BaseXBar::headerLatency, gem5::Packet::id, gem5::InvalidPortID, gem5::Packet::isClean(), isDestination(), gem5::Packet::isEviction(), gem5::Packet::isExpressSnoop(), gem5::Packet::isSecure(), gem5::Packet::isWrite(), gem5::SnoopFilter::lookupRequest(), gem5::Packet::makeResponse(), maxOutstandingSnoopCheck, maxRoutingTableSizeCheck, gem5::BaseXBar::memSidePorts, gem5::Named::name(), gem5::Port::name(), gem5::Packet::needsResponse(), outstandingCMO, outstandingSnoop, panic_if, gem5::Packet::payloadDelay, pendingDelete, gem5::BaseXBar::pktCount, gem5::BaseXBar::pktSize, gem5::Packet::print(), gem5::Packet::req, reqLayers, gem5::statistics::ScalarBase< Derived, Stor >::reset(), respLayers, gem5::BaseXBar::routeTo, gem5::Packet::satisfied(), gem5::Packet::setBlockCached(), gem5::Packet::setExpressSnoop(), sinkPacket(), gem5::Packet::snoopDelay, snoopFilter, snoops, snoopTraffic, system, gem5::BaseXBar::transDist, gem5::SnoopFilter::updateResponse(), and gem5::MemCmd::WriteClean.

Referenced by gem5::CoherentXBar::CoherentXBarResponsePort::recvTimingReq().

◆ recvTimingResp()

bool gem5::CoherentXBar::recvTimingResp	(	PacketPtr	pkt,
		PortID	mem_side_port_id )

protected

◆ recvTimingSnoopReq()

void gem5::CoherentXBar::recvTimingSnoopReq	(	PacketPtr	pkt,
		PortID	mem_side_port_id )

protected

◆ recvTimingSnoopResp()

bool gem5::CoherentXBar::recvTimingSnoopResp	(	PacketPtr	pkt,
		PortID	cpu_side_port_id )

protected

Definition at line 570 of file coherent_xbar.cc.

References gem5::BaseXBar::calcPacketTiming(), gem5::Clocked::clockEdge(), gem5::Clocked::clockPeriod(), gem5::Packet::cmdToIndex(), gem5::BaseXBar::cpuSidePorts, gem5::curTick(), DPRINTF, gem5::Packet::getSize(), gem5::Packet::hasData(), gem5::Packet::headerDelay, gem5::BaseXBar::headerLatency, gem5::InvalidPortID, gem5::Packet::isExpressSnoop(), gem5::BaseXBar::memSidePorts, gem5::Port::name(), outstandingSnoop, gem5::Packet::payloadDelay, gem5::BaseXBar::pktCount, gem5::BaseXBar::pktSize, gem5::Packet::print(), gem5::Packet::req, respLayers, gem5::BaseXBar::responseLatency, gem5::BaseXBar::routeTo, snoopFilter, snoopLayers, snoopResponseLatency, snoopRespPorts, snoops, snoopTraffic, gem5::BaseXBar::transDist, gem5::SnoopFilter::updateSnoopForward(), and gem5::SnoopFilter::updateSnoopResponse().

Referenced by gem5::CoherentXBar::CoherentXBarResponsePort::recvTimingSnoopResp().

◆ regStats()

void gem5::CoherentXBar::regStats ( )

virtual

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 gem5::BaseXBar.

Definition at line 1127 of file coherent_xbar.cc.

References gem5::statistics::Distribution::init(), gem5::BaseXBar::regStats(), snoopFanout, and snoopPorts.

◆ sinkPacket()

bool gem5::CoherentXBar::sinkPacket ( const PacketPtr pkt ) const

protected

Determine if the crossbar should sink the packet, as opposed to forwarding it, or responding.

Definition at line 1088 of file coherent_xbar.cc.

References gem5::Packet::cacheResponding(), gem5::Packet::isBlockCached(), gem5::Packet::isCleanEviction(), gem5::Packet::isRead(), gem5::Packet::isWrite(), gem5::Packet::needsResponse(), gem5::Packet::needsWritable(), pointOfCoherency, and gem5::Packet::responderHadWritable().

Referenced by recvAtomicBackdoor(), and recvTimingReq().

Member Data Documentation

◆ maxOutstandingSnoopCheck

const unsigned int gem5::CoherentXBar::maxOutstandingSnoopCheck

protected

Maximum number of outstading snoops sanity check.

Definition at line 291 of file coherent_xbar.hh.

Referenced by recvTimingReq().

◆ maxRoutingTableSizeCheck

const unsigned int gem5::CoherentXBar::maxRoutingTableSizeCheck

protected

Maximum routing table size sanity check.

Definition at line 294 of file coherent_xbar.hh.

Referenced by recvTimingReq().

◆ outstandingCMO

std::unordered_map<PacketId, PacketPtr> gem5::CoherentXBar::outstandingCMO

protected

Store the outstanding cache maintenance that we are expecting snoop responses from so we can determine when we received all snoop responses and if any of the agents satisfied the request.

Definition at line 275 of file coherent_xbar.hh.

Referenced by recvAtomicBackdoor(), and recvTimingReq().

◆ outstandingSnoop

std::unordered_set<RequestPtr> gem5::CoherentXBar::outstandingSnoop

protected

Store the outstanding requests that we are expecting snoop responses from so we can determine which snoop responses we generated and which ones were merely forwarded.

Definition at line 268 of file coherent_xbar.hh.

Referenced by recvTimingReq(), and recvTimingSnoopResp().

◆ pendingDelete

std::unique_ptr<Packet> gem5::CoherentXBar::pendingDelete

protected

Upstream caches need this packet until true is returned, so hold it for deletion until a subsequent call.

Definition at line 306 of file coherent_xbar.hh.

Referenced by recvTimingReq().

◆ pointOfCoherency

const bool gem5::CoherentXBar::pointOfCoherency

protected

Is this crossbar the point of coherency?

Definition at line 297 of file coherent_xbar.hh.

Referenced by forwardPacket(), isDestination(), and sinkPacket().

◆ pointOfUnification

const bool gem5::CoherentXBar::pointOfUnification

protected

Is this crossbar the point of unification?

Definition at line 300 of file coherent_xbar.hh.

Referenced by isDestination().

◆ reqLayers

std::vector<ReqLayer*> gem5::CoherentXBar::reqLayers

protected

Declare the layers of this crossbar, one vector for requests, one for responses, and one for snoop responses.

Definition at line 79 of file coherent_xbar.hh.

Referenced by CoherentXBar(), recvReqRetry(), recvTimingReq(), and ~CoherentXBar().

◆ respLayers

std::vector<RespLayer*> gem5::CoherentXBar::respLayers

protected

Definition at line 80 of file coherent_xbar.hh.

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

◆ snoopFanout

statistics::Distribution gem5::CoherentXBar::snoopFanout

protected

Definition at line 435 of file coherent_xbar.hh.

Referenced by forwardAtomic(), forwardTiming(), and regStats().

◆ snoopFilter

SnoopFilter* gem5::CoherentXBar::snoopFilter

protected

A snoop filter that tracks cache line residency and can restrict the broadcast needed for probes.

NULL denotes an absent filter.

Definition at line 285 of file coherent_xbar.hh.

Referenced by forwardAtomic(), init(), recvAtomicBackdoor(), recvAtomicSnoop(), recvTimingReq(), recvTimingResp(), recvTimingSnoopReq(), and recvTimingSnoopResp().

◆ snoopLayers

std::vector<SnoopRespLayer*> gem5::CoherentXBar::snoopLayers

protected

Definition at line 81 of file coherent_xbar.hh.

Referenced by CoherentXBar(), recvTimingSnoopResp(), and ~CoherentXBar().

◆ snoopPorts

std::vector<QueuedResponsePort*> gem5::CoherentXBar::snoopPorts

protected

Definition at line 261 of file coherent_xbar.hh.

Referenced by forwardAtomic(), forwardFunctional(), forwardTiming(), init(), and regStats().

◆ snoopResponseLatency

const Cycles gem5::CoherentXBar::snoopResponseLatency

protected

Cycles of snoop response latency.

Definition at line 288 of file coherent_xbar.hh.

Referenced by recvTimingSnoopResp().

◆ snoopRespPorts

std::vector<SnoopRespPort*> gem5::CoherentXBar::snoopRespPorts

protected

Definition at line 259 of file coherent_xbar.hh.

Referenced by CoherentXBar(), recvTimingSnoopResp(), and ~CoherentXBar().

◆ snoops

statistics::Scalar gem5::CoherentXBar::snoops

protected

Definition at line 433 of file coherent_xbar.hh.

Referenced by recvAtomicSnoop(), recvTimingReq(), recvTimingSnoopReq(), and recvTimingSnoopResp().

◆ snoopTraffic

statistics::Scalar gem5::CoherentXBar::snoopTraffic

protected

Definition at line 434 of file coherent_xbar.hh.

Referenced by recvAtomicSnoop(), recvTimingReq(), recvTimingSnoopReq(), and recvTimingSnoopResp().

◆ system

System* gem5::CoherentXBar::system

protected

Keep a pointer to the system to be allow to querying memory system properties.

Definition at line 281 of file coherent_xbar.hh.

Referenced by forwardAtomic(), forwardFunctional(), forwardTiming(), recvAtomicBackdoor(), recvFunctional(), recvTimingReq(), and recvTimingResp().

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

mem/coherent_xbar.hh
mem/coherent_xbar.cc

Classes

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ CoherentXBar()

◆ ~CoherentXBar()

Member Function Documentation

◆ forwardAtomic() [1/2]

◆ forwardAtomic() [2/2]

◆ forwardFunctional()

◆ forwardPacket()

◆ forwardTiming() [1/2]

◆ forwardTiming() [2/2]

◆ init()

◆ isDestination()

◆ recvAtomicBackdoor()

◆ recvAtomicSnoop()

◆ recvFunctional()

◆ recvFunctionalSnoop()

◆ recvMemBackdoorReq()

◆ recvReqRetry()

◆ recvTimingReq()

◆ recvTimingResp()

◆ recvTimingSnoopReq()

◆ recvTimingSnoopResp()

◆ regStats()

◆ sinkPacket()

Member Data Documentation

◆ maxOutstandingSnoopCheck

◆ maxRoutingTableSizeCheck

◆ outstandingCMO

◆ outstandingSnoop

◆ pendingDelete

◆ pointOfCoherency

◆ pointOfUnification

◆ reqLayers

◆ respLayers

◆ snoopFanout

◆ snoopFilter

◆ snoopLayers

◆ snoopPorts

◆ snoopResponseLatency

◆ snoopRespPorts

◆ snoops

◆ snoopTraffic

◆ system