#include <tree_plru_rp.hh>

Inheritance diagram for gem5::replacement_policy::TreePLRU:

Classes
struct	TreePLRUReplData
	Tree-PLRU-specific implementation of replacement data. More...

Public Types
typedef TreePLRURPParams	Params

Public Types inherited from gem5::replacement_policy::Base
typedef BaseReplacementPolicyParams	Params

Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params

Public Member Functions
	TreePLRU (const Params &p)

	~TreePLRU ()=default

void	invalidate (const std::shared_ptr< ReplacementData > &replacement_data) override
	Invalidate replacement data to set it as the next probable victim.

void	touch (const std::shared_ptr< ReplacementData > &replacement_data) const override
	Touch an entry to update its replacement data.

void	reset (const std::shared_ptr< ReplacementData > &replacement_data) const override
	Reset replacement data.

ReplaceableEntry *	getVictim (const ReplacementCandidates &candidates) const override
	Find replacement victim using TreePLRU bits.

std::shared_ptr< ReplacementData >	instantiateEntry () override
	Instantiate a replacement data entry.

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

virtual	~Base ()=default

virtual void	touch (const std::shared_ptr< ReplacementData > &replacement_data, const PacketPtr pkt)
	Update replacement data.

virtual void	reset (const std::shared_ptr< ReplacementData > &replacement_data, const PacketPtr pkt)
	Reset replacement data.

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

Private Types
typedef std::vector< bool >	PLRUTree
	Instead of implementing the tree itself with pointers, it is implemented as an array of bits.

Private Attributes
const uint64_t	numLeaves
	Number of leaves that share a single replacement data.

uint64_t	count
	Count of the number of sharers of a replacement data.

PLRUTree *	treeInstance
	Holds the latest temporary tree instance created by instantiateEntry().

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 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 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

Definition at line 86 of file tree_plru_rp.hh.

Member Typedef Documentation

◆ Params

typedef TreePLRURPParams gem5::replacement_policy::TreePLRU::Params

Definition at line 158 of file tree_plru_rp.hh.

◆ PLRUTree

typedef std::vector<bool> gem5::replacement_policy::TreePLRU::PLRUTree

private

Instead of implementing the tree itself with pointers, it is implemented as an array of bits.

The index of the node defines its position in the tree, and its parent. Index 0 represents the root, 1 is its left node, and 2 is its right node. Then, in a BFS fashion this is expanded to the following nodes (3 and 4 are respectively 1's left and right nodes, and 5 and 6 are 2's left and right nodes, and so on).

i.e., the following trees are equivalent in this representation: ____1____ 0 1 0 1 1 0 A B C D E F G H

1 0 1 0 1 1 0

Notice that the replacement data entries are not represented in the tree to avoid unnecessary storage costs.

Definition at line 108 of file tree_plru_rp.hh.

Constructor & Destructor Documentation

◆ TreePLRU()

gem5::replacement_policy::TreePLRU::TreePLRU ( const Params & p )

Definition at line 104 of file tree_plru_rp.cc.

References fatal_if, and numLeaves.

◆ ~TreePLRU()

gem5::replacement_policy::TreePLRU::~TreePLRU ( )

default

Member Function Documentation

◆ getVictim()

ReplaceableEntry * gem5::replacement_policy::TreePLRU::getVictim ( const ReplacementCandidates & candidates ) const

overridevirtual

Find replacement victim using TreePLRU bits.

It is assumed that all candidates share the same replacement data tree.

Parameters

candidates Replacement candidates, selected by indexing policy.

Returns: Replacement entry to be replaced.

Implements gem5::replacement_policy::Base.

Definition at line 171 of file tree_plru_rp.cc.

References gem5::replacement_policy::leftSubtreeIndex(), numLeaves, and gem5::replacement_policy::rightSubtreeIndex().

◆ instantiateEntry()

std::shared_ptr< ReplacementData > gem5::replacement_policy::TreePLRU::instantiateEntry ( )

overridevirtual

Instantiate a replacement data entry.

Consecutive calls to this function use the same tree up to numLeaves. When numLeaves replacement data have been created, a new tree is generated, and the counter is reset. Therefore, it is essential that entries that share the same replacement data call this function consecutively.

Returns: A shared pointer to the new replacement data.

Implements gem5::replacement_policy::Base.

Definition at line 199 of file tree_plru_rp.cc.

References count, numLeaves, and treeInstance.

◆ invalidate()

void gem5::replacement_policy::TreePLRU::invalidate ( const std::shared_ptr< ReplacementData > & replacement_data )

overridevirtual

Invalidate replacement data to set it as the next probable victim.

Makes tree leaf of replacement data the LRU (tree bits point to it).

Parameters

replacement_data Replacement data to be invalidated.

Implements gem5::replacement_policy::Base.

Definition at line 112 of file tree_plru_rp.cc.

References gem5::replacement_policy::isRightSubtree(), and gem5::replacement_policy::parentIndex().

◆ reset()

void gem5::replacement_policy::TreePLRU::reset ( const std::shared_ptr< ReplacementData > & replacement_data ) const

overridevirtual

Reset replacement data.

Used when an entry is inserted. Provides the same functionality as touch().

Parameters

replacement_data Replacement data to be reset.

Implements gem5::replacement_policy::Base.

Definition at line 163 of file tree_plru_rp.cc.

References touch().

◆ touch()

void gem5::replacement_policy::TreePLRU::touch ( const std::shared_ptr< ReplacementData > & replacement_data ) const

overridevirtual

Touch an entry to update its replacement data.

Makes tree leaf of replacement data the MRU.

Parameters

replacement_data Replacement data to be touched.

Implements gem5::replacement_policy::Base.

Definition at line 137 of file tree_plru_rp.cc.

References gem5::replacement_policy::isRightSubtree(), and gem5::replacement_policy::parentIndex().

Referenced by reset().

Member Data Documentation

◆ count

uint64_t gem5::replacement_policy::TreePLRU::count

private

Count of the number of sharers of a replacement data.

It is used when instantiating entries to share a replacement data among many replaceable entries.

Definition at line 120 of file tree_plru_rp.hh.

Referenced by instantiateEntry().

◆ numLeaves

const uint64_t gem5::replacement_policy::TreePLRU::numLeaves

private

Number of leaves that share a single replacement data.

Definition at line 113 of file tree_plru_rp.hh.

Referenced by getVictim(), instantiateEntry(), and TreePLRU().

◆ treeInstance

PLRUTree* gem5::replacement_policy::TreePLRU::treeInstance

private

Holds the latest temporary tree instance created by instantiateEntry().

Definition at line 125 of file tree_plru_rp.hh.

Referenced by instantiateEntry().

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

mem/cache/replacement_policies/tree_plru_rp.hh
mem/cache/replacement_policies/tree_plru_rp.cc

Classes

Public Types

Public Member Functions

Private Types

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Params

◆ PLRUTree

Constructor & Destructor Documentation

◆ TreePLRU()

◆ ~TreePLRU()

Member Function Documentation

◆ getVictim()

◆ instantiateEntry()

◆ invalidate()

◆ reset()

◆ touch()

Member Data Documentation

◆ count

◆ numLeaves

◆ treeInstance