A set associative indexing policy. More...

#include <set_associative.hh>

Inheritance diagram for gem5::SetAssociative:

Public Types
typedef SetAssociativeParams	Params
	Convenience typedef.

Public Types inherited from gem5::BaseIndexingPolicy
typedef BaseIndexingPolicyParams	Params
	Convenience typedef.

Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params

Public Member Functions
	SetAssociative (const Params &p)
	Construct and initialize this policy.

	~SetAssociative ()
	Destructor.

std::vector< ReplaceableEntry * >	getPossibleEntries (const Addr addr) const override
	Find all possible entries for insertion and replacement of an address.

Addr	regenerateAddr (const Addr tag, const ReplaceableEntry *entry) const override
	Regenerate an entry's address from its tag and assigned set and way.

Public Member Functions inherited from gem5::BaseIndexingPolicy
	BaseIndexingPolicy (const Params &p)
	Construct and initialize this policy.

	~BaseIndexingPolicy ()
	Destructor.

void	setEntry (ReplaceableEntry *entry, const uint64_t index)
	Associate a pointer to an entry to its physical counterpart.

ReplaceableEntry *	getEntry (const uint32_t set, const uint32_t way) const
	Get an entry based on its set and way.

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

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.

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

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	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

Protected Member Functions
virtual uint32_t	extractSet (const Addr addr) const
	Apply a hash function to calculate address set.

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.

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.

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.

Protected Attributes inherited from gem5::BaseIndexingPolicy
const unsigned	assoc
	The associativity.

const uint32_t	numSets
	The number of sets in the cache.

const int	setShift
	The amount to shift the address to get the set.

const unsigned	setMask
	Mask out all bits that aren't part of the set index.

std::vector< std::vector< ReplaceableEntry * > >	sets
	The cache sets.

const int	tagShift
	The amount to shift the address to get the tag.

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.

Detailed Description

A set associative indexing policy.

See also: gem5 Memory System

The set associative indexing policy has an immutable/identity mapping, so a value x is always mapped to set x, independent of the way, that is, Hash(A, 0) = Hash(A, 1) = Hash(A, N-1), where N is the number of ways.

For example, let's assume address A maps to set 3 on way 0. This policy makes so that A is also mappable to set 3 on every other way. Visually, the possible locations of A are, for a table with 4 ways and 8 sets: Way 0 1 2 3 Set _ _ _ _ 0 |_| |_| |_| |_| 1 |_| |_| |_| |_| 2 |_| |_| |_| |_| 3 |X| |X| |X| |X| 4 |_| |_| |_| |_| 5 |_| |_| |_| |_| 6 |_| |_| |_| |_| 7 |_| |_| |_| |_|

Definition at line 82 of file set_associative.hh.

Member Typedef Documentation

◆ Params

typedef SetAssociativeParams gem5::SetAssociative::Params

Convenience typedef.

Definition at line 97 of file set_associative.hh.

Constructor & Destructor Documentation

◆ SetAssociative()

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

Construct and initialize this policy.

Definition at line 54 of file set_associative.cc.

◆ ~SetAssociative()

gem5::SetAssociative::~SetAssociative ( )

inline

Destructor.

Definition at line 107 of file set_associative.hh.

Member Function Documentation

◆ extractSet()

uint32_t gem5::SetAssociative::extractSet ( const Addr addr ) const

protectedvirtual

Apply a hash function to calculate address set.

Parameters

addr	The address to calculate the set for.

Returns: The set index for given combination of address and way.

Reimplemented in gem5::prefetch::StridePrefetcherHashedSetAssociative.

Definition at line 60 of file set_associative.cc.

References gem5::X86ISA::addr, gem5::BaseIndexingPolicy::setMask, and gem5::BaseIndexingPolicy::setShift.

Referenced by getPossibleEntries().

◆ getPossibleEntries()

std::vector< ReplaceableEntry * > gem5::SetAssociative::getPossibleEntries ( const Addr addr ) const

overridevirtual

Find all possible entries for insertion and replacement of an address.

Should be called immediately before ReplacementPolicy's findVictim() not to break cache resizing. Returns entries in all ways belonging to the set of the address.

Parameters

addr	The addr to a find possible entries for.

Returns: The possible entries.

Implements gem5::BaseIndexingPolicy.

Definition at line 73 of file set_associative.cc.

References gem5::X86ISA::addr, extractSet(), and gem5::BaseIndexingPolicy::sets.

◆ regenerateAddr()

Addr gem5::SetAssociative::regenerateAddr	(	const Addr	tag,
		const ReplaceableEntry *	entry ) const

overridevirtual

Regenerate an entry's address from its tag and assigned set and way.

Parameters

tag	The tag bits.
entry	The entry.

Returns: the entry's original addr value.

Implements gem5::BaseIndexingPolicy.

Definition at line 66 of file set_associative.cc.

References gem5::ReplaceableEntry::getSet(), gem5::BaseIndexingPolicy::setShift, and gem5::BaseIndexingPolicy::tagShift.

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

mem/cache/tags/indexing_policies/set_associative.hh
mem/cache/tags/indexing_policies/set_associative.cc

Public Types

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Params

Constructor & Destructor Documentation

◆ SetAssociative()

◆ ~SetAssociative()

Member Function Documentation

◆ extractSet()

◆ getPossibleEntries()

◆ regenerateAddr()