A coherent cache that can be arranged in flexible topologies. More...

#include <cache.hh>

Inheritance diagram for gem5::Cache:

Public Member Functions
	Cache (const CacheParams &p)
	Instantiates a basic cache object.

bool	sendMSHRQueuePacket (MSHR *mshr) override
	Take an MSHR, turn it into a suitable downstream packet, and send it out.

Public Member Functions inherited from gem5::BaseCache
void	regProbePoints () override
	Registers probes.

	BaseCache (const BaseCacheParams &p, unsigned blk_size)

	~BaseCache ()

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

Port &	getPort (const std::string &if_name, PortID idx=InvalidPortID) override
	Get a port with a given name and index.

unsigned	getBlockSize () const
	Query block size of a cache.

const AddrRangeList &	getAddrRanges () const

MSHR *	allocateMissBuffer (PacketPtr pkt, Tick time, bool sched_send=true)

void	allocateWriteBuffer (PacketPtr pkt, Tick time)

bool	isBlocked () const
	Returns true if the cache is blocked for accesses.

void	setBlocked (BlockedCause cause)
	Marks the access path of the cache as blocked for the given cause.

void	clearBlocked (BlockedCause cause)
	Marks the cache as unblocked for the given cause.

void	schedMemSideSendEvent (Tick time)
	Schedule a send event for the memory-side port.

bool	inCache (Addr addr, bool is_secure) const

bool	hasBeenPrefetched (Addr addr, bool is_secure) const

bool	hasBeenPrefetched (Addr addr, bool is_secure, RequestorID requestor) const

bool	inMissQueue (Addr addr, bool is_secure) const

void	incMissCount (PacketPtr pkt)

void	incHitCount (PacketPtr pkt)

bool	coalesce () const
	Checks if the cache is coalescing writes.

void	writebackVisitor (CacheBlk &blk)
	Cache block visitor that writes back dirty cache blocks using functional writes.

void	invalidateVisitor (CacheBlk &blk)
	Cache block visitor that invalidates all blocks in the cache.

bool	sendWriteQueuePacket (WriteQueueEntry *wq_entry)
	Similar to sendMSHR, but for a write-queue entry instead.

void	serialize (CheckpointOut &cp) const override
	Serialize the state of the caches.

void	unserialize (CheckpointIn &cp) override
	Unserialize an 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	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.

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	regStats ()
	Callback to set stat parameters.

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
void	promoteWholeLineWrites (PacketPtr pkt)
	Turn line-sized writes into WriteInvalidate transactions.

bool	access (PacketPtr pkt, CacheBlk *&blk, Cycles &lat, PacketList &writebacks) override
	Does all the processing necessary to perform the provided request.

void	handleTimingReqHit (PacketPtr pkt, CacheBlk *blk, Tick request_time) override

void	handleTimingReqMiss (PacketPtr pkt, CacheBlk *blk, Tick forward_time, Tick request_time) override

void	recvTimingReq (PacketPtr pkt) override
	Performs the access specified by the request.

void	doWritebacks (PacketList &writebacks, Tick forward_time) override
	Insert writebacks into the write buffer.

void	doWritebacksAtomic (PacketList &writebacks) override
	Send writebacks down the memory hierarchy in atomic mode.

void	serviceMSHRTargets (MSHR mshr, const PacketPtr pkt, CacheBlk blk) override
	Service non-deferred MSHR targets using the received response.

void	recvTimingSnoopReq (PacketPtr pkt) override
	Snoops bus transactions to maintain coherence.

void	recvTimingSnoopResp (PacketPtr pkt) override
	Handle a snoop response.

Cycles	handleAtomicReqMiss (PacketPtr pkt, CacheBlk *&blk, PacketList &writebacks) override
	Handle a request in atomic mode that missed in this cache.

Tick	recvAtomic (PacketPtr pkt) override
	Performs the access specified by the request.

Tick	recvAtomicSnoop (PacketPtr pkt) override
	Snoop for the provided request in the cache and return the estimated time taken.

void	satisfyRequest (PacketPtr pkt, CacheBlk *blk, bool deferred_response=false, bool pending_downgrade=false) override
	Perform any necessary updates to the block and perform any data exchange between the packet and the block.

void	doTimingSupplyResponse (PacketPtr req_pkt, const uint8_t *blk_data, bool already_copied, bool pending_inval)

uint32_t	handleSnoop (PacketPtr pkt, CacheBlk *blk, bool is_timing, bool is_deferred, bool pending_inval)
	Perform an upward snoop if needed, and update the block state (possibly invalidating the block).

PacketPtr	evictBlock (CacheBlk *blk) override
	Evict a cache block.

PacketPtr	cleanEvictBlk (CacheBlk *blk)
	Create a CleanEvict request for the given block.

PacketPtr	createMissPacket (PacketPtr cpu_pkt, CacheBlk *blk, bool needs_writable, bool is_whole_line_write) const override
	Create an appropriate downstream bus request packet.

bool	isCachedAbove (PacketPtr pkt, bool is_timing=true)
	Send up a snoop request and find cached copies.

Protected Member Functions inherited from gem5::BaseCache
void	markInService (MSHR *mshr, bool pending_modified_resp)
	Mark a request as in service (sent downstream in the memory system), effectively making this MSHR the ordering point.

void	markInService (WriteQueueEntry *entry)

bool	allocOnFill (MemCmd cmd) const
	Determine whether we should allocate on a fill or not.

Addr	regenerateBlkAddr (CacheBlk *blk)
	Regenerate block address using tags.

Cycles	calculateTagOnlyLatency (const uint32_t delay, const Cycles lookup_lat) const
	Calculate latency of accesses that only touch the tag array.

Cycles	calculateAccessLatency (const CacheBlk *blk, const uint32_t delay, const Cycles lookup_lat) const
	Calculate access latency in ticks given a tag lookup latency, and whether access was a hit or miss.

void	handleTimingReqMiss (PacketPtr pkt, MSHR mshr, CacheBlk blk, Tick forward_time, Tick request_time)

void	handleUncacheableWriteResp (PacketPtr pkt)
	Handling the special case of uncacheable write responses to make recvTimingResp less cluttered.

virtual void	recvTimingResp (PacketPtr pkt)
	Handles a response (cache line fill/write ack) from the bus.

virtual void	functionalAccess (PacketPtr pkt, bool from_cpu_side)
	Performs the access specified by the request.

void	updateBlockData (CacheBlk *blk, const PacketPtr cpkt, bool has_old_data)
	Update the data contents of a block.

void	cmpAndSwap (CacheBlk *blk, PacketPtr pkt)
	Handle doing the Compare and Swap function for SPARC.

QueueEntry *	getNextQueueEntry ()
	Return the next queue entry to service, either a pending miss from the MSHR queue, a buffered write from the write buffer, or something from the prefetcher.

void	writebackTempBlockAtomic ()
	Send the outstanding tempBlock writeback.

bool	updateCompressionData (CacheBlk &blk, const uint64_t data, PacketList &writebacks)
	When a block is overwriten, its compression information must be updated, and it may need to be recompressed.

void	maintainClusivity (bool from_cache, CacheBlk *blk)
	Maintain the clusivity of this cache by potentially invalidating a block.

bool	handleEvictions (std::vector< CacheBlk * > &evict_blks, PacketList &writebacks)
	Try to evict the given blocks.

CacheBlk *	handleFill (PacketPtr pkt, CacheBlk *blk, PacketList &writebacks, bool allocate)
	Handle a fill operation caused by a received packet.

CacheBlk *	allocateBlock (const PacketPtr pkt, PacketList &writebacks)
	Allocate a new block and perform any necessary writebacks.

void	evictBlock (CacheBlk *blk, PacketList &writebacks)
	Evict a cache block.

void	invalidateBlock (CacheBlk *blk)
	Invalidate a cache block.

PacketPtr	writebackBlk (CacheBlk *blk)
	Create a writeback request for the given block.

PacketPtr	writecleanBlk (CacheBlk *blk, Request::Flags dest, PacketId id)
	Create a writeclean request for the given block.

virtual void	memWriteback () override
	Write back dirty blocks in the cache using functional accesses.

virtual void	memInvalidate () override
	Invalidates all blocks in the cache.

bool	isDirty () const
	Determine if there are any dirty blocks in the cache.

bool	inRange (Addr addr) const
	Determine if an address is in the ranges covered by this cache.

Tick	nextQueueReadyTime () const
	Find next request ready time from among possible sources.

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
const bool	doFastWrites
	This cache should allocate a block on a line-sized write miss.

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.

Protected Attributes inherited from gem5::BaseCache
CpuSidePort	cpuSidePort

MemSidePort	memSidePort

gem5::BaseCache::CacheAccessorImpl	accessor

MSHRQueue	mshrQueue
	Miss status registers.

WriteQueue	writeBuffer
	Write/writeback buffer.

BaseTags *	tags
	Tag and data Storage.

compression::Base *	compressor
	Compression method being used.

partitioning_policy::PartitionManager *	partitionManager
	Partitioning manager.

prefetch::Base *	prefetcher
	Prefetcher.

ProbePointArg< CacheAccessProbeArg > *	ppHit
	To probe when a cache hit occurs.

ProbePointArg< CacheAccessProbeArg > *	ppMiss
	To probe when a cache miss occurs.

ProbePointArg< CacheAccessProbeArg > *	ppFill
	To probe when a cache fill occurs.

ProbePointArg< CacheDataUpdateProbeArg > *	ppDataUpdate
	To probe when the contents of a block are updated.

WriteAllocator *const	writeAllocator
	The writeAllocator drive optimizations for streaming writes.

TempCacheBlk *	tempBlock
	Temporary cache block for occasional transitory use.

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

const bool	writebackClean
	Determine if clean lines should be written back or not.

PacketPtr	tempBlockWriteback
	Writebacks from the tempBlock, resulting on the response path in atomic mode, must happen after the call to recvAtomic has finished (for the right ordering of the packets).

EventFunctionWrapper	writebackTempBlockAtomicEvent
	An event to writeback the tempBlock after recvAtomic finishes.

const unsigned	blkSize
	Block size of this cache.

const Cycles	lookupLatency
	The latency of tag lookup of a cache.

const Cycles	dataLatency
	The latency of data access of a cache.

const Cycles	forwardLatency
	This is the forward latency of the cache.

const Cycles	fillLatency
	The latency to fill a cache block.

const Cycles	responseLatency
	The latency of sending reponse to its upper level cache/core on a linefill.

const bool	sequentialAccess
	Whether tags and data are accessed sequentially.

const int	numTarget
	The number of targets for each MSHR.

bool	forwardSnoops
	Do we forward snoops from mem side port through to cpu side port?

const enums::Clusivity	clusivity
	Clusivity with respect to the upstream cache, determining if we fill into both this cache and the cache above on a miss.

const bool	isReadOnly
	Is this cache read only, for example the instruction cache, or table-walker cache.

const bool	replaceExpansions
	when a data expansion of a compressed block happens it will not be able to co-allocate where it is at anymore.

const bool	moveContractions
	Similar to data expansions, after a block improves its compression, it may need to be moved elsewhere compatible with the new compression factor, or, if not required by the compaction method, it may be moved to co-allocate with an existing block and thus free an entry.

uint8_t	blocked
	Bit vector of the blocking reasons for the access path.

uint64_t	order
	Increasing order number assigned to each incoming request.

Cycles	blockedCycle
	Stores time the cache blocked for statistics.

MSHR *	noTargetMSHR
	Pointer to the MSHR that has no targets.

Counter	missCount
	The number of misses to trigger an exit event.

const AddrRangeList	addrRanges
	The address range to which the cache responds on the CPU side.

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::BaseCache
enum	BlockedCause { Blocked_NoMSHRs = MSHRQueue_MSHRs , Blocked_NoWBBuffers = MSHRQueue_WriteBuffer , Blocked_NoTargets , NUM_BLOCKED_CAUSES }
	Reasons for caches to be blocked. More...

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::BaseCache
System *	system
	System we are currently operating in.

gem5::BaseCache::CacheStats	stats

Public Attributes inherited from gem5::ClockedObject
PowerState *	powerState

Protected Types inherited from gem5::BaseCache
enum	MSHRQueueIndex { MSHRQueue_MSHRs , MSHRQueue_WriteBuffer }
	Indexes to enumerate the MSHR queues. More...

Detailed Description

A coherent cache that can be arranged in flexible topologies.

Definition at line 67 of file cache.hh.

Constructor & Destructor Documentation

◆ Cache()

gem5::Cache::Cache ( const CacheParams & p )

Instantiates a basic cache object.

Definition at line 69 of file cache.cc.

References gem5::MipsISA::p.

Member Function Documentation

◆ access()

bool gem5::Cache::access	(	PacketPtr	pkt,
		CacheBlk *&	blk,
		Cycles &	lat,
		PacketList &	writebacks )

overrideprotectedvirtual

Does all the processing necessary to perform the provided request.

Parameters

pkt	The memory request to perform.
blk	The cache block to be updated.
lat	The latency of the access.
writebacks	List for any writebacks that need to be performed.

Returns: Boolean indicating whether the request was satisfied.

Reimplemented from gem5::BaseCache.

Definition at line 161 of file cache.cc.

References gem5::BaseCache::access(), DPRINTF, gem5::BaseCache::evictBlock(), gem5::BaseTags::findBlock(), gem5_assert, gem5::Packet::getAddr(), gem5::BaseCache::isReadOnly, gem5::Packet::isRequest(), gem5::Packet::isSecure(), gem5::CacheEntry::isValid(), gem5::Packet::isWrite(), gem5::BaseCache::lookupLatency, gem5::Named::name(), gem5::Packet::print(), gem5::Packet::req, and gem5::BaseCache::tags.

◆ cleanEvictBlk()

PacketPtr gem5::Cache::cleanEvictBlk ( CacheBlk * blk )

protected

Create a CleanEvict request for the given block.

Parameters

blk	The block to evict.

Returns: The CleanEvict request for the block.

Definition at line 972 of file cache.cc.

References gem5::Packet::allocate(), gem5::BaseCache::blkSize, gem5::MemCmd::CleanEvict, gem5::CacheBlk::DirtyBit, DPRINTF, gem5::CacheBlk::getTaskId(), gem5::TaggedEntry::isSecure(), gem5::CacheBlk::isSet(), gem5::CacheEntry::isValid(), gem5::Packet::print(), gem5::BaseCache::regenerateBlkAddr(), gem5::Request::SECURE, gem5::Request::wbRequestorId, and gem5::BaseCache::writebackClean.

Referenced by evictBlock().

◆ createMissPacket()

PacketPtr gem5::Cache::createMissPacket	(	PacketPtr	cpu_pkt,
		CacheBlk *	blk,
		bool	needs_writable,
		bool	is_whole_line_write ) const

overrideprotectedvirtual

Create an appropriate downstream bus request packet.

Creates a new packet with the request to be send to the memory below, or nullptr if the current request in cpu_pkt should just be forwarded on.

Parameters

cpu_pkt	The miss packet that needs to be satisfied.
blk	The referenced block, can be nullptr.
needs_writable	Indicates that the block must be writable even if the request in cpu_pkt doesn't indicate that.
is_whole_line_write	True if there are writes for the whole line

Returns: A packet send to the memory below

Implements gem5::BaseCache.

Definition at line 492 of file cache.cc.

References gem5::Packet::allocate(), gem5::BaseCache::blkSize, gem5::BaseCache::clusivity, gem5::Packet::cmd, DPRINTF, gem5::Packet::getAddr(), gem5::Packet::getBlockAddr(), gem5::Packet::hasSharers(), gem5::MemCmd::InvalidateReq, gem5::Packet::isClean(), gem5::Packet::isEviction(), gem5::Packet::isLLSC(), gem5::BaseCache::isReadOnly, gem5::CacheBlk::isSet(), gem5::Packet::isUpgrade(), gem5::CacheEntry::isValid(), gem5::Packet::needsResponse(), gem5::Packet::print(), gem5::MemCmd::ReadCleanReq, gem5::MemCmd::ReadExReq, gem5::MemCmd::ReadSharedReq, gem5::Packet::req, gem5::MemCmd::SCUpgradeFailReq, gem5::MemCmd::SCUpgradeReq, gem5::Packet::setHasSharers(), gem5::MemCmd::StoreCondFailReq, gem5::MemCmd::UpgradeReq, gem5::CacheBlk::WritableBit, and gem5::MemCmd::WriteLineReq.

Referenced by handleAtomicReqMiss().

◆ doTimingSupplyResponse()

void gem5::Cache::doTimingSupplyResponse	(	PacketPtr	req_pkt,
		const uint8_t *	blk_data,
		bool	already_copied,
		bool	pending_inval )

protected

◆ doWritebacks()

void gem5::Cache::doWritebacks	(	PacketList &	writebacks,
		Tick	forward_time )

overrideprotectedvirtual

Insert writebacks into the write buffer.

Implements gem5::BaseCache.

Definition at line 190 of file cache.cc.

References gem5::BaseCache::allocateWriteBuffer(), gem5::MemCmd::CleanEvict, gem5::Packet::cmd, isCachedAbove(), gem5::Packet::setBlockCached(), gem5::MemCmd::WritebackClean, gem5::BaseCache::writebackClean, gem5::MemCmd::WritebackDirty, and gem5::MemCmd::WriteClean.

Referenced by handleSnoop().

◆ doWritebacksAtomic()

void gem5::Cache::doWritebacksAtomic ( PacketList & writebacks )

overrideprotectedvirtual

Send writebacks down the memory hierarchy in atomic mode.

Implements gem5::BaseCache.

Definition at line 232 of file cache.cc.

References gem5::Packet::cmd, isCachedAbove(), gem5::BaseCache::memSidePort, gem5::RequestPort::sendAtomic(), gem5::MemCmd::WritebackDirty, and gem5::MemCmd::WriteClean.

Referenced by handleSnoop().

◆ evictBlock()

PacketPtr gem5::Cache::evictBlock ( CacheBlk * blk )

nodiscardoverrideprotectedvirtual

Evict a cache block.

Performs a writeback if necesssary and invalidates the block

Parameters

blk	Block to invalidate

Returns: A packet with the writeback, can be nullptr

Implements gem5::BaseCache.

Definition at line 961 of file cache.cc.

References cleanEvictBlk(), gem5::CacheBlk::DirtyBit, gem5::BaseCache::invalidateBlock(), gem5::CacheBlk::isSet(), gem5::BaseCache::writebackBlk(), and gem5::BaseCache::writebackClean.

◆ handleAtomicReqMiss()

Cycles gem5::Cache::handleAtomicReqMiss	(	PacketPtr	pkt,
		CacheBlk *&	blk,
		PacketList &	writebacks )

overrideprotectedvirtual

Handle a request in atomic mode that missed in this cache.

Creates a downstream request, sends it to the memory below and handles the response. As we are in atomic mode all operations are performed immediately.

Parameters

pkt	The packet with the requests
blk	The referenced block
writebacks	A list with packets for any performed writebacks

Returns: Cycles for handling the request

Implements gem5::BaseCache.

Definition at line 578 of file cache.cc.

References gem5::WriteAllocator::allocate(), gem5::BaseCache::allocOnFill(), gem5::BaseCache::blkSize, gem5::Packet::cmd, gem5::Packet::copyError(), createMissPacket(), DPRINTF, gem5::Packet::fromCache(), gem5::BaseCache::handleFill(), gem5::BaseCache::invalidateBlock(), gem5::Packet::isError(), gem5::Packet::isEviction(), gem5::Packet::isInvalidate(), gem5::Packet::isRead(), gem5::Packet::isResponse(), gem5::CacheEntry::isValid(), gem5::Packet::isWholeLineWrite(), gem5::Packet::isWrite(), gem5::BaseCache::maintainClusivity(), gem5::Packet::makeAtomicResponse(), gem5::BaseCache::memSidePort, gem5::Packet::needsResponse(), gem5::Packet::needsWritable(), gem5::CacheBlk::print(), gem5::Packet::print(), gem5::Packet::req, satisfyRequest(), gem5::RequestPort::sendAtomic(), gem5::Clocked::ticksToCycles(), gem5::MemCmd::UpgradeResp, gem5::BaseCache::writeAllocator, and gem5::MemCmd::WriteClean.

◆ handleSnoop()

uint32_t gem5::Cache::handleSnoop	(	PacketPtr	pkt,
		CacheBlk *	blk,
		bool	is_timing,
		bool	is_deferred,
		bool	pending_inval )

protected

Perform an upward snoop if needed, and update the block state (possibly invalidating the block).

Also create a response if required.

Parameters

pkt	Snoop packet
blk	Cache block being snooped
is_timing	Timing or atomic for the response
is_deferred	Is this a deferred snoop or not?
pending_inval	Do we have a pending invalidation?

Returns: The snoop delay incurred by the upwards snoop

Definition at line 1045 of file cache.cc.

References gem5::BaseCache::blkSize, gem5::Packet::cacheResponding(), gem5::CacheBlk::clearCoherenceBits(), gem5::Clocked::clockEdge(), gem5::BaseCache::compressor, gem5::Packet::copyResponderFlags(), gem5::BaseCache::cpuSidePort, gem5::CacheBlk::data, gem5::CacheBlk::DirtyBit, doTimingSupplyResponse(), doWritebacks(), doWritebacksAtomic(), DPRINTF, gem5::BaseCache::forwardLatency, gem5::BaseCache::forwardSnoops, gem5_assert, gem5::Packet::getAddr(), gem5::compression::Base::getDecompressionLatency(), gem5::Packet::hasData(), gem5::Packet::hasSharers(), gem5::Packet::headerDelay, gem5::Packet::id, gem5::BaseCache::invalidateBlock(), gem5::Packet::isBlockCached(), gem5::Packet::isClean(), gem5::Packet::isInvalidate(), gem5::Packet::isRead(), gem5::BaseCache::isReadOnly, gem5::Packet::isRequest(), gem5::Packet::isResponse(), gem5::CacheBlk::isSet(), gem5::CacheEntry::isValid(), gem5::Packet::makeAtomicResponse(), gem5::Packet::mustCheckAbove(), gem5::Named::name(), gem5::Packet::needsResponse(), gem5::Packet::needsWritable(), panic_if, gem5::Packet::payloadDelay, gem5::CacheBlk::print(), gem5::Packet::print(), gem5::Packet::req, gem5::Packet::satisfied(), gem5::ResponsePort::sendAtomicSnoop(), gem5::ResponsePort::sendTimingSnoopReq(), gem5::Packet::setBlockCached(), gem5::Packet::setCacheResponding(), gem5::Packet::setDataFromBlock(), gem5::Packet::setExpressSnoop(), gem5::Packet::setHasSharers(), gem5::Packet::setResponderHadWritable(), gem5::Packet::setSatisfied(), gem5::CacheBlk::WritableBit, and gem5::BaseCache::writecleanBlk().

Referenced by recvAtomicSnoop(), recvTimingSnoopReq(), and serviceMSHRTargets().

◆ handleTimingReqHit()

void gem5::Cache::handleTimingReqHit	(	PacketPtr	pkt,
		CacheBlk *	blk,
		Tick	request_time )

overrideprotectedvirtual

Reimplemented from gem5::BaseCache.

Definition at line 313 of file cache.cc.

References gem5::BaseCache::handleTimingReqHit(), and gem5::Packet::req.

◆ handleTimingReqMiss()

void gem5::Cache::handleTimingReqMiss	(	PacketPtr	pkt,
		CacheBlk *	blk,
		Tick	forward_time,
		Tick	request_time )

overrideprotectedvirtual

Implements gem5::BaseCache.

Definition at line 324 of file cache.cc.

References gem5::BaseCache::allocateMissBuffer(), gem5::BaseCache::allocateWriteBuffer(), gem5::BaseCache::blkSize, gem5::Packet::cmd, gem5::BaseCache::CacheStats::cmdStats(), gem5::BaseCache::cpuSidePort, gem5::Queue< Entry >::findMatch(), gem5::Packet::getBlockAddr(), gem5::Packet::getSize(), gem5::BaseCache::handleTimingReqMiss(), gem5::Packet::isCleanInvalidateRequest(), gem5::Packet::isRead(), gem5::Packet::isSecure(), gem5::MemCmd::isSWPrefetch(), gem5::CacheEntry::isValid(), gem5::Packet::isWrite(), gem5::MemCmd::LockedRMWWriteReq, gem5::Packet::makeTimingResponse(), gem5::BaseCache::mshrQueue, gem5::BaseCache::CacheCmdStats::mshrUncacheable, gem5::Packet::needsResponse(), gem5::X86ISA::pf, gem5::Packet::req, gem5::QueuedResponsePort::schedTimingResp(), and gem5::BaseCache::stats.

◆ isCachedAbove()

bool gem5::Cache::isCachedAbove	(	PacketPtr	pkt,
		bool	is_timing = true )

protected

Send up a snoop request and find cached copies.

If cached copies are found, set the BLOCK_CACHED flag in pkt.

Definition at line 1392 of file cache.cc.

References gem5::Packet::cacheResponding(), gem5::Packet::cmd, gem5::BaseCache::cpuSidePort, gem5::BaseCache::forwardSnoops, gem5::Packet::isBlockCached(), gem5::Packet::isEviction(), gem5::ResponsePort::sendAtomicSnoop(), gem5::Packet::senderState, gem5::ResponsePort::sendTimingSnoopReq(), gem5::Packet::setExpressSnoop(), and gem5::MemCmd::WriteClean.

Referenced by doWritebacks(), and doWritebacksAtomic().

◆ promoteWholeLineWrites()

void gem5::Cache::promoteWholeLineWrites ( PacketPtr pkt )

protected

Turn line-sized writes into WriteInvalidate transactions.

Definition at line 301 of file cache.cc.

References gem5::BaseCache::blkSize, gem5::Packet::cmd, doFastWrites, DPRINTF, gem5::Packet::getOffset(), gem5::Packet::getSize(), gem5::Packet::isMaskedWrite(), gem5::MemCmd::WriteLineReq, and gem5::MemCmd::WriteReq.

Referenced by recvAtomic(), and recvTimingReq().

◆ recvAtomic()

Tick gem5::Cache::recvAtomic ( PacketPtr pkt )

overrideprotectedvirtual

Performs the access specified by the request.

Parameters

pkt	The request to perform.

Returns: The number of ticks required for the access.

Reimplemented from gem5::BaseCache.

Definition at line 668 of file cache.cc.

References gem5::Packet::cacheResponding(), DPRINTF, gem5::BaseCache::memSidePort, gem5::Packet::needsWritable(), gem5::Packet::print(), promoteWholeLineWrites(), gem5::BaseCache::recvAtomic(), gem5::Packet::req, gem5::Packet::responderHadWritable(), and gem5::RequestPort::sendAtomic().

◆ recvAtomicSnoop()

Tick gem5::Cache::recvAtomicSnoop ( PacketPtr pkt )

overrideprotectedvirtual

Snoop for the provided request in the cache and return the estimated time taken.

Parameters

pkt	The memory request to snoop

Returns: The number of ticks required for the snoop.

Implements gem5::BaseCache.

Definition at line 1379 of file cache.cc.

References gem5::Clocked::clockPeriod(), gem5::BaseTags::findBlock(), gem5::Packet::getAddr(), handleSnoop(), gem5::BaseCache::inRange(), gem5::Packet::isSecure(), gem5::BaseCache::lookupLatency, and gem5::BaseCache::tags.

◆ recvTimingReq()

void gem5::Cache::recvTimingReq ( PacketPtr pkt )

overrideprotectedvirtual

Performs the access specified by the request.

Parameters

pkt	The request to perform.

Reimplemented from gem5::BaseCache.

Definition at line 418 of file cache.cc.

References gem5::Packet::cacheResponding(), DPRINTF, gem5::Packet::headerDelay, gem5::BaseCache::memSidePort, gem5::Packet::needsWritable(), gem5::Packet::payloadDelay, gem5::BaseCache::pendingDelete, gem5::BaseTags::print(), gem5::Packet::print(), promoteWholeLineWrites(), gem5::BaseCache::recvTimingReq(), gem5::Packet::responderHadWritable(), gem5::RequestPort::sendTimingReq(), gem5::Packet::setCacheResponding(), gem5::Packet::setExpressSnoop(), and gem5::BaseCache::tags.

◆ recvTimingSnoopReq()

void gem5::Cache::recvTimingSnoopReq ( PacketPtr pkt )

overrideprotectedvirtual

Snoops bus transactions to maintain coherence.

Parameters

pkt	The current bus transaction.

Implements gem5::BaseCache.

Definition at line 1261 of file cache.cc.

References gem5::BaseCache::blkSize, gem5::Clocked::clockPeriod(), gem5::Packet::cmd, doTimingSupplyResponse(), DPRINTF, gem5::BaseTags::findBlock(), gem5::Queue< Entry >::findMatch(), gem5::Packet::getAddr(), gem5::Packet::getBlockAddr(), gem5::Packet::getConstPtr(), gem5::MSHR::getNumTargets(), gem5::WriteQueueEntry::getNumTargets(), gem5::WriteQueueEntry::getTarget(), handleSnoop(), gem5::MSHR::handleSnoop(), gem5::Packet::hasSharers(), gem5::BaseCache::inRange(), gem5::Packet::isEviction(), gem5::Packet::isInvalidate(), gem5::Packet::isRead(), gem5::Packet::isSecure(), gem5::QueueEntry::isUncacheable(), gem5::BaseCache::lookupLatency, gem5::BaseCache::markInService(), gem5::BaseCache::mshrQueue, gem5::Packet::mustCheckAbove(), gem5::Packet::needsResponse(), gem5::Packet::needsWritable(), gem5::BaseCache::numTarget, gem5::BaseCache::order, gem5::QueueEntry::Target::pkt, gem5::MSHR::print(), gem5::Packet::print(), gem5::Packet::req, gem5::Packet::setBlockCached(), gem5::Packet::setCacheResponding(), gem5::Packet::setHasSharers(), gem5::Packet::setResponderHadWritable(), gem5::Packet::snoopDelay, gem5::BaseCache::tags, warn, gem5::MemCmd::WritebackDirty, gem5::BaseCache::writeBuffer, and gem5::MemCmd::WriteClean.

◆ recvTimingSnoopResp()

void gem5::Cache::recvTimingSnoopResp ( PacketPtr pkt )

overrideprotectedvirtual

Handle a snoop response.

Parameters

pkt	Snoop response packet

Implements gem5::BaseCache.

Definition at line 267 of file cache.cc.

References gem5::Clocked::clockEdge(), gem5::Packet::cmd, DPRINTF, gem5::BaseCache::forwardLatency, gem5::Packet::getAddr(), gem5::MemCmd::HardPFResp, gem5::Packet::headerDelay, gem5::Packet::isSecure(), gem5::BaseCache::memSidePort, outstandingSnoop, gem5::Packet::payloadDelay, gem5::Packet::print(), gem5::BaseCache::recvTimingResp(), gem5::Packet::req, and gem5::QueuedRequestPort::schedTimingSnoopResp().

◆ satisfyRequest()

void gem5::Cache::satisfyRequest	(	PacketPtr	pkt,
		CacheBlk *	blk,
		bool	deferred_response = false,
		bool	pending_downgrade = false )

overrideprotectedvirtual

Perform any necessary updates to the block and perform any data exchange between the packet and the block.

The flags of the packet are also set accordingly.

Parameters

pkt	Request packet from upstream that hit a block
blk	Cache block that the packet hit
deferred_response	Whether this request originally missed
pending_downgrade	Whether the writable flag is to be removed

Reimplemented from gem5::BaseCache.

Definition at line 78 of file cache.cc.

References gem5::BaseCache::blkSize, gem5::CacheBlk::clearCoherenceBits(), gem5::Packet::cmd, gem5::CacheBlk::DirtyBit, gem5::Packet::fromCache(), gem5::Packet::getSize(), gem5::Packet::hasSharers(), gem5::Packet::isRead(), gem5::CacheBlk::isSet(), gem5::Packet::needsWritable(), gem5::MemCmd::ReadCleanReq, gem5::MemCmd::ReadExReq, gem5::BaseCache::satisfyRequest(), gem5::MemCmd::SCUpgradeFailReq, gem5::Packet::setCacheResponding(), gem5::Packet::setHasSharers(), and gem5::CacheBlk::WritableBit.

Referenced by handleAtomicReqMiss(), and serviceMSHRTargets().

◆ sendMSHRQueuePacket()

bool gem5::Cache::sendMSHRQueuePacket ( MSHR * mshr )

overridevirtual

Take an MSHR, turn it into a suitable downstream packet, and send it out.

This construct allows a queue entry to choose a suitable approach based on its type.

Parameters

mshr	The MSHR to turn into a packet and send

Returns: True if the port is waiting for a retry

Reimplemented from gem5::BaseCache.

Definition at line 1420 of file cache.cc.

References gem5::QueueEntry::blkAddr, gem5::BaseCache::Blocked_NoMSHRs, gem5::Packet::cacheResponding(), gem5::BaseCache::clearBlocked(), gem5::Packet::cmd, gem5::BaseCache::cpuSidePort, DPRINTF, gem5::BaseTags::findBlock(), gem5::MSHRQueue::forceDeallocateTarget(), gem5::BaseCache::forwardSnoops, gem5::Packet::getAddr(), gem5::MSHR::getTarget(), gem5::MemCmd::HardPFReq, gem5::Packet::hasSharers(), gem5::Packet::isBlockCached(), gem5::Packet::isSecure(), gem5::QueueEntry::isSecure, gem5::BaseCache::markInService(), gem5::BaseCache::mshrQueue, outstandingSnoop, gem5::QueueEntry::Target::pkt, gem5::Packet::print(), gem5::MipsISA::r, gem5::Packet::req, gem5::Packet::senderState, gem5::BaseCache::sendMSHRQueuePacket(), gem5::ResponsePort::sendTimingSnoopReq(), gem5::Packet::setExpressSnoop(), and gem5::BaseCache::tags.

◆ serviceMSHRTargets()

void gem5::Cache::serviceMSHRTargets	(	MSHR *	mshr,
		const PacketPtr	pkt,
		CacheBlk *	blk )

overrideprotectedvirtual

Service non-deferred MSHR targets using the received response.

Iterates through the list of targets that can be serviced with the current response.

Parameters

mshr	The MSHR that corresponds to the reponse
pkt	The response packet
blk	The reference block

Implements gem5::BaseCache.

Definition at line 699 of file cache.cc.

References gem5::BaseCache::blkSize, gem5::CacheBlk::clearCoherenceBits(), gem5::Clocked::clockEdge(), gem5::Packet::cmd, gem5::BaseCache::CacheStats::cmdStats(), gem5::Packet::copyError(), gem5::Packet::copyResponderFlags(), gem5::BaseCache::cpuSidePort, gem5::CacheBlk::DirtyBit, DPRINTF, gem5::MSHR::extractServiceableTargets(), gem5::MSHR::Target::FromCPU, gem5::MSHR::Target::FromPrefetcher, gem5::MSHR::Target::FromSnoop, gem5::Packet::getConstPtr(), gem5::Packet::getOffset(), gem5::Packet::getSize(), gem5::MSHR::getTarget(), handleSnoop(), gem5::MemCmd::HardPFReq, gem5::Packet::hasData(), gem5::MSHR::TargetList::hasFromCache, gem5::MSHR::hasLockedRMWReadTarget(), gem5::MSHR::hasPostDowngrade(), gem5::MSHR::hasPostInvalidate(), gem5::Packet::hasRespData(), gem5::Packet::headerDelay, gem5::BaseCache::invalidateBlock(), gem5::MemCmd::InvalidateResp, gem5::Packet::isError(), gem5::MSHR::isForward, gem5::Packet::isInvalidate(), gem5::Packet::isRead(), gem5::BaseCache::isReadOnly, gem5::CacheBlk::isSet(), gem5::MemCmd::isSWPrefetch(), gem5::CacheEntry::isValid(), gem5::MemCmd::LockedRMWReadReq, gem5::MemCmd::LockedRMWWriteResp, gem5::BaseCache::maintainClusivity(), gem5::Packet::makeTimingResponse(), gem5::Packet::matchAddr(), gem5::System::maxRequestors(), gem5::BaseCache::CacheCmdStats::missLatency, gem5::Named::name(), gem5::Packet::needsWritable(), panic, panic_if, gem5::Packet::payloadDelay, gem5::QueueEntry::Target::pkt, gem5::MSHR::popTarget(), gem5::Packet::print(), gem5::CacheBlk::ReadableBit, gem5::MemCmd::ReadResp, gem5::MemCmd::ReadRespWithInvalidate, gem5::Packet::req, gem5::BaseCache::responseLatency, satisfyRequest(), gem5::QueuedResponsePort::schedTimingResp(), gem5::MemCmd::SCUpgradeFailReq, gem5::CacheBlk::setCoherenceBits(), gem5::Packet::setData(), gem5::CacheBlk::setPrefetched(), gem5::BaseCache::stats, gem5::MemCmd::StoreCondFailReq, gem5::MemCmd::StoreCondReq, gem5::BaseCache::system, gem5::MSHR::updateLockedRMWReadTarget(), gem5::MemCmd::UpgradeFailResp, gem5::MSHR::wasWholeLineWrite, gem5::CacheBlk::WritableBit, and gem5::MemCmd::WriteLineReq.

Member Data Documentation

◆ doFastWrites

const bool gem5::Cache::doFastWrites

protected

This cache should allocate a block on a line-sized write miss.

Definition at line 73 of file cache.hh.

Referenced by promoteWholeLineWrites().

◆ outstandingSnoop

std::unordered_set<RequestPtr> gem5::Cache::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 80 of file cache.hh.

Referenced by recvTimingSnoopResp(), and sendMSHRQueuePacket().

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

mem/cache/cache.hh
mem/cache/cache.cc

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Cache()

Member Function Documentation

◆ access()

◆ cleanEvictBlk()

◆ createMissPacket()

◆ doTimingSupplyResponse()

◆ doWritebacks()

◆ doWritebacksAtomic()

◆ evictBlock()

◆ handleAtomicReqMiss()

◆ handleSnoop()

◆ handleTimingReqHit()

◆ handleTimingReqMiss()

◆ isCachedAbove()

◆ promoteWholeLineWrites()

◆ recvAtomic()

◆ recvAtomicSnoop()

◆ recvTimingReq()

◆ recvTimingSnoopReq()

◆ recvTimingSnoopResp()

◆ satisfyRequest()

◆ sendMSHRQueuePacket()

◆ serviceMSHRTargets()

Member Data Documentation

◆ doFastWrites

◆ outstandingSnoop