A set associative indexing policy. More...

#include <set_associative.hh>

Inheritance diagram for SetAssociative:

Public Types
typedef SetAssociativeParams	Params
	Convenience typedef. More...

Public Types inherited from BaseIndexingPolicy
typedef BaseIndexingPolicyParams	Params
	Convenience typedef. More...

Public Types inherited from SimObject
typedef SimObjectParams	Params

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

	~SetAssociative ()
	Destructor. More...

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

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

Public Member Functions inherited from BaseIndexingPolicy
	BaseIndexingPolicy (const Params *p)
	Construct and initialize this policy. More...

	~BaseIndexingPolicy ()
	Destructor. More...

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

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

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

Public Member Functions inherited from SimObject
const Params *	params () const

	SimObject (const Params *_params)

virtual	~SimObject ()

virtual const std::string	name () const

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

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

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

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

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

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 EventManager
	EventManager (EventManager &em)

	EventManager (EventManager *em)

	EventManager (EventQueue *eq)

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)

void	setCurTick (Tick newVal)

Public Member Functions inherited from Serializable
	Serializable ()

virtual	~Serializable ()

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

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

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

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

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

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

Public Member Functions inherited from Stats::Group
	Group ()=delete

	Group (const Group &)=delete

Group &	operator= (const Group &)=delete

	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 (Stats::Info *info)
	Register a stat with this group. More...

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

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

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

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

Additional Inherited Members
Static Public Member Functions inherited from SimObject
static void	serializeAll (CheckpointOut &cp)
	Serialize 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 Public Member Functions inherited from Serializable
static const std::string &	currentSection ()
	Get the fully-qualified name of the active section. More...

static void	serializeAll (const std::string &cpt_dir)

static void	unserializeGlobals (CheckpointIn &cp)

Static Public Attributes inherited from Serializable
static int	ckptCount = 0

static int	ckptMaxCount = 0

static int	ckptPrevCount = -1

Protected Member Functions inherited from Drainable
	Drainable ()

virtual	~Drainable ()

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

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

Protected Attributes inherited from BaseIndexingPolicy
const unsigned	assoc
	The associativity. More...

const uint32_t	numSets
	The number of sets in the cache. More...

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

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

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

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

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

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

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 SetAssociative::Params

Convenience typedef.

Definition at line 97 of file set_associative.hh.

Constructor & Destructor Documentation

◆ SetAssociative()

SetAssociative::SetAssociative ( const Params * p )

Construct and initialize this policy.

Definition at line 54 of file set_associative.cc.

Referenced by getPossibleEntries().

◆ ~SetAssociative()

SetAssociative::~SetAssociative ( )

inline

Destructor.

Definition at line 107 of file set_associative.hh.

References getPossibleEntries(), and regenerateAddr().

Member Function Documentation

◆ extractSet()

uint32_t SetAssociative::extractSet ( const Addr addr ) const

private

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.

Definition at line 60 of file set_associative.cc.

References BaseIndexingPolicy::setMask, and BaseIndexingPolicy::setShift.

Referenced by getPossibleEntries().

◆ getPossibleEntries()

std::vector< ReplaceableEntry * > 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