A basic cache tag store. More...

#include <base_set_assoc.hh>

Inheritance diagram for gem5::BaseSetAssoc:

Public Types
typedef BaseSetAssocParams	Params
	Convenience typedef. More...

Public Types inherited from gem5::BaseTags
typedef BaseTagsParams	Params

Public Types inherited from gem5::ClockedObject
using	Params = ClockedObjectParams
	Parameters of ClockedObject. More...

Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params

Public Member Functions
	BaseSetAssoc (const Params &p)
	Construct and initialize this tag store. More...

virtual	~BaseSetAssoc ()
	Destructor. More...

void	tagsInit () override
	Initialize blocks as CacheBlk instances. More...

void	invalidate (CacheBlk *blk) override
	This function updates the tags when a block is invalidated. More...

CacheBlk *	accessBlock (const PacketPtr pkt, Cycles &lat) override
	Access block and update replacement data. More...

CacheBlk *	findVictim (Addr addr, const bool is_secure, const std::size_t size, std::vector< CacheBlk * > &evict_blks) override
	Find replacement victim based on address. More...

void	insertBlock (const PacketPtr pkt, CacheBlk *blk) override
	Insert the new block into the cache and update replacement data. More...

void	moveBlock (CacheBlk src_blk, CacheBlk dest_blk) override
	Move a block's metadata to another location decided by the replacement policy. More...

virtual void	setWayAllocationMax (int ways) override
	Limit the allocation for the cache ways. More...

virtual int	getWayAllocationMax () const override
	Get the way allocation mask limit. More...

Addr	regenerateBlkAddr (const CacheBlk *blk) const override
	Regenerate the block address from the tag and indexing location. More...

void	forEachBlk (std::function< void(CacheBlk &)> visitor) override
	Visit each block in the tags and apply a visitor. More...

bool	anyBlk (std::function< bool(CacheBlk &)> visitor) override
	Find if any of the blocks satisfies a condition. More...

Public Member Functions inherited from gem5::BaseTags
	BaseTags (const Params &p)

virtual	~BaseTags ()
	Destructor. More...

void	cleanupRefs ()
	Average in the reference count for valid blocks when the simulation exits. More...

void	computeStats ()
	Computes stats just prior to dump event. More...

std::string	print ()
	Print all tags used. More...

virtual CacheBlk *	findBlock (Addr addr, bool is_secure) const
	Finds the block in the cache without touching it. More...

virtual ReplaceableEntry *	findBlockBySetAndWay (int set, int way) const
	Find a block given set and way. More...

Addr	blkAlign (Addr addr) const
	Align an address to the block size. More...

int	extractBlkOffset (Addr addr) const
	Calculate the block offset of an address. More...

virtual Addr	extractTag (const Addr addr) const
	Generate the tag from the given address. More...

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

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

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

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

	SimObject (const Params &p)

virtual	~SimObject ()

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

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

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

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

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

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

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

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

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

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

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

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

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

Public Member Functions inherited from gem5::EventManager
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. More...

void	setCurTick (Tick newVal)

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

	EventManager (EventManager *em)

	EventManager (EventQueue *eq)

Public Member Functions inherited from gem5::Serializable
	Serializable ()

virtual	~Serializable ()

void	serializeSection (CheckpointOut &cp, const char *name) const
	Serialize an object into a new section. More...

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

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

void	unserializeSection (CheckpointIn &cp, const std::string &name)

Public Member Functions inherited from gem5::Drainable
DrainState	drainState () const
	Return the current drain state of an object. More...

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

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

virtual	~Group ()

virtual void	regStats ()
	Callback to set stat parameters. More...

virtual void	resetStats ()
	Callback to reset stats. More...

virtual void	preDumpStats ()
	Callback before stats are dumped. More...

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

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

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

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

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

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

	Group ()=delete

	Group (const Group &)=delete

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. 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 Attributes
unsigned	allocAssoc
	The allocatable associativity of the cache (alloc mask). More...

std::vector< CacheBlk >	blks
	The cache blocks. More...

const bool	sequentialAccess
	Whether tags and data are accessed sequentially. More...

replacement_policy::Base *	replacementPolicy
	Replacement policy. More...

Protected Attributes inherited from gem5::BaseTags
const unsigned	blkSize
	The block size of the cache. More...

const Addr	blkMask
	Mask out all bits that aren't part of the block offset. More...

const unsigned	size
	The size of the cache. More...

const Cycles	lookupLatency
	The tag lookup latency of the cache. More...

System *	system
	System we are currently operating in. More...

BaseIndexingPolicy *	indexingPolicy
	Indexing policy. More...

const unsigned	warmupBound
	The number of tags that need to be touched to meet the warmup percentage. More...

bool	warmedUp
	Marked true when the cache is warmed up. More...

const unsigned	numBlocks
	the number of blocks in the cache More...

std::unique_ptr< uint8_t[]>	dataBlks
	The data blocks, 1 per cache block. More...

gem5::BaseTags::BaseTagStats	stats

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

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

Additional Inherited Members
Static Public Member Functions inherited from gem5::SimObject
static void	serializeAll (const std::string &cpt_dir)
	Create a checkpoint by serializing all SimObjects in the system. More...

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

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

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

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

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

Public Attributes inherited from gem5::ClockedObject
PowerState *	powerState

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

virtual	~Drainable ()

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

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

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

	Clocked (Clocked &)=delete

Clocked &	operator= (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...

Detailed Description

A basic cache tag store.

See also: gem5 Memory System

The BaseSetAssoc placement policy divides the cache into s sets of w cache lines (ways).

Definition at line 75 of file base_set_assoc.hh.

Member Typedef Documentation

◆ Params

typedef BaseSetAssocParams gem5::BaseSetAssoc::Params

Convenience typedef.

Definition at line 92 of file base_set_assoc.hh.

Constructor & Destructor Documentation

◆ BaseSetAssoc()

gem5::BaseSetAssoc::BaseSetAssoc ( const Params & p )

Construct and initialize this tag store.

Definition at line 55 of file base_set_assoc.cc.

References gem5::BaseTags::blkSize, fatal, fatal_if, gem5::isPowerOf2(), and gem5::MipsISA::p.

◆ ~BaseSetAssoc()

virtual gem5::BaseSetAssoc::~BaseSetAssoc ( )

inlinevirtual

Destructor.

Definition at line 102 of file base_set_assoc.hh.

Member Function Documentation

◆ accessBlock()

CacheBlk* gem5::BaseSetAssoc::accessBlock	(	const PacketPtr	pkt,
		Cycles &	lat
	)

inlineoverridevirtual

Access block and update replacement data.

May not succeed, in which case nullptr is returned. This has all the implications of a cache access and should only be used as such. Returns the tag lookup latency as a side effect.

Parameters

pkt	The packet holding the address to find.
lat	The latency of the tag lookup.

Returns: Pointer to the cache block if found.

Implements gem5::BaseTags.

Definition at line 127 of file base_set_assoc.hh.

References allocAssoc, gem5::BaseTags::BaseTagStats::dataAccesses, gem5::BaseTags::findBlock(), gem5::Packet::getAddr(), gem5::CacheBlk::increaseRefCount(), gem5::Packet::isSecure(), gem5::BaseTags::lookupLatency, gem5::ReplaceableEntry::replacementData, replacementPolicy, sequentialAccess, gem5::BaseTags::stats, gem5::BaseTags::BaseTagStats::tagAccesses, and gem5::replacement_policy::Base::touch().

◆ anyBlk()

bool gem5::BaseSetAssoc::anyBlk ( std::function< bool(CacheBlk &)> visitor )

inlineoverridevirtual

Find if any of the blocks satisfies a condition.

The visitor should be a std::function that takes a cache block reference as its parameter. The visitor will terminate the traversal early if the condition is satisfied.

Parameters

visitor Visitor to call on each block.

Implements gem5::BaseTags.

Definition at line 242 of file base_set_assoc.hh.

References blks.

◆ findVictim()

CacheBlk* gem5::BaseSetAssoc::findVictim	(	Addr	addr,
		const bool	is_secure,
		const std::size_t	size,
		std::vector< CacheBlk * > &	evict_blks
	)

inlineoverridevirtual

Find replacement victim based on address.

The list of evicted blocks only contains the victim.

Parameters

addr	Address to find a victim for.
is_secure	True if the target memory space is secure.
size	Size, in bits, of new block to allocate.
evict_blks	Cache blocks to be evicted.

Returns: Cache block to be replaced.

Implements gem5::BaseTags.

Definition at line 168 of file base_set_assoc.hh.

References gem5::X86ISA::addr, gem5::BaseIndexingPolicy::getPossibleEntries(), gem5::replacement_policy::Base::getVictim(), gem5::BaseTags::indexingPolicy, and replacementPolicy.

◆ forEachBlk()

void gem5::BaseSetAssoc::forEachBlk ( std::function< void(CacheBlk &)> visitor )

inlineoverridevirtual

Visit each block in the tags and apply a visitor.

The visitor should be a std::function that takes a cache block reference as its parameter.

Parameters

visitor Visitor to call on each block.

Implements gem5::BaseTags.

Definition at line 236 of file base_set_assoc.hh.

References blks.

◆ getWayAllocationMax()

virtual int gem5::BaseSetAssoc::getWayAllocationMax ( ) const

inlineoverridevirtual

Get the way allocation mask limit.

Returns: The maximum number of ways available for replacement.

Reimplemented from gem5::BaseTags.

Definition at line 220 of file base_set_assoc.hh.

References allocAssoc.

◆ insertBlock()

void gem5::BaseSetAssoc::insertBlock	(	const PacketPtr	pkt,
		CacheBlk *	blk
	)

inlineoverridevirtual

Insert the new block into the cache and update replacement data.

Parameters

pkt	Packet holding the address to update
blk	The block to update.

Reimplemented from gem5::BaseTags.

Definition at line 192 of file base_set_assoc.hh.

References gem5::BaseTags::insertBlock(), gem5::ReplaceableEntry::replacementData, replacementPolicy, gem5::replacement_policy::Base::reset(), gem5::BaseTags::stats, and gem5::BaseTags::BaseTagStats::tagsInUse.

◆ invalidate()

void gem5::BaseSetAssoc::invalidate ( CacheBlk * blk )

overridevirtual

This function updates the tags when a block is invalidated.

It also updates the replacement data.

Parameters

blk	The block to invalidate.

Reimplemented from gem5::BaseTags.

Definition at line 89 of file base_set_assoc.cc.

References gem5::replacement_policy::Base::invalidate(), gem5::BaseTags::invalidate(), gem5::ReplaceableEntry::replacementData, replacementPolicy, gem5::BaseTags::stats, and gem5::BaseTags::BaseTagStats::tagsInUse.

◆ moveBlock()

void gem5::BaseSetAssoc::moveBlock	(	CacheBlk *	src_blk,
		CacheBlk *	dest_blk
	)

overridevirtual

Move a block's metadata to another location decided by the replacement policy.

It behaves as a swap, however, since the destination block should be invalid, the result is a move.

Parameters

src_blk	The source block.
dest_blk	The destination block. Must be invalid.

Reimplemented from gem5::BaseTags.

Definition at line 101 of file base_set_assoc.cc.

References gem5::replacement_policy::Base::invalidate(), gem5::BaseTags::moveBlock(), gem5::ReplaceableEntry::replacementData, replacementPolicy, and gem5::replacement_policy::Base::reset().

◆ regenerateBlkAddr()

Addr gem5::BaseSetAssoc::regenerateBlkAddr ( const CacheBlk * blk ) const

inlineoverridevirtual

Regenerate the block address from the tag and indexing location.

Parameters

block The block.

Returns: the block address.

Implements gem5::BaseTags.

Definition at line 231 of file base_set_assoc.hh.

References gem5::TaggedEntry::getTag(), gem5::BaseTags::indexingPolicy, and gem5::BaseIndexingPolicy::regenerateAddr().

◆ setWayAllocationMax()

virtual void gem5::BaseSetAssoc::setWayAllocationMax ( int ways )

inlineoverridevirtual

Limit the allocation for the cache ways.

Parameters

ways	The maximum number of ways available for replacement.

Reimplemented from gem5::BaseTags.

Definition at line 210 of file base_set_assoc.hh.

References allocAssoc, and fatal_if.

◆ tagsInit()

void gem5::BaseSetAssoc::tagsInit ( )

overridevirtual

Initialize blocks as CacheBlk instances.

Implements gem5::BaseTags.

Definition at line 70 of file base_set_assoc.cc.

References blks, gem5::BaseTags::blkSize, gem5::CacheBlk::data, gem5::BaseTags::dataBlks, gem5::BaseTags::indexingPolicy, gem5::replacement_policy::Base::instantiateEntry(), gem5::BaseTags::numBlocks, gem5::ReplaceableEntry::replacementData, replacementPolicy, and gem5::BaseIndexingPolicy::setEntry().

Member Data Documentation

◆ allocAssoc

unsigned gem5::BaseSetAssoc::allocAssoc

protected

The allocatable associativity of the cache (alloc mask).

Definition at line 79 of file base_set_assoc.hh.

Referenced by accessBlock(), getWayAllocationMax(), and setWayAllocationMax().

◆ blks

std::vector<CacheBlk> gem5::BaseSetAssoc::blks

protected

The cache blocks.

Definition at line 82 of file base_set_assoc.hh.

Referenced by anyBlk(), forEachBlk(), and tagsInit().

◆ replacementPolicy

replacement_policy::Base* gem5::BaseSetAssoc::replacementPolicy

protected

Replacement policy.

Definition at line 88 of file base_set_assoc.hh.

Referenced by accessBlock(), findVictim(), insertBlock(), invalidate(), moveBlock(), and tagsInit().

◆ sequentialAccess

const bool gem5::BaseSetAssoc::sequentialAccess

protected

Whether tags and data are accessed sequentially.

Definition at line 85 of file base_set_assoc.hh.

Referenced by accessBlock().

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

mem/cache/tags/base_set_assoc.hh
mem/cache/tags/base_set_assoc.cc

Public Types

Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Params

Constructor & Destructor Documentation

◆ BaseSetAssoc()

◆ ~BaseSetAssoc()

Member Function Documentation

◆ accessBlock()

◆ anyBlk()

◆ findVictim()

◆ forEachBlk()

◆ getWayAllocationMax()

◆ insertBlock()

◆ invalidate()

◆ moveBlock()

◆ regenerateBlkAddr()

◆ setWayAllocationMax()

◆ tagsInit()

Member Data Documentation

◆ allocAssoc

◆ blks

◆ replacementPolicy

◆ sequentialAccess