gem5::prefetch::PIF Class Reference

#include <pif.hh>

Inheritance diagram for gem5::prefetch::PIF:

Classes
struct	CompactorEntry
	The compactor tracks retired instructions addresses, leveraging the spatial and temporal locality among instructions for compaction. More...
struct	IndexEntry
class	PrefetchListenerPC
	Probe Listener to handle probe events from the CPU. More...

Public Member Functions
	PIF (const PIFPrefetcherParams &p)
	~PIF ()=default
void	calculatePrefetch (const PrefetchInfo &pfi, std::vector< AddrPriority > &addresses)
void	addEventProbeRetiredInsts (SimObject *obj, const char *name)
	Add a SimObject and a probe name to monitor the retired instructions.
Public Member Functions inherited from gem5::prefetch::Queued
	Queued (const QueuedPrefetcherParams &p)
virtual	~Queued ()
void	notify (const PacketPtr &pkt, const PrefetchInfo &pfi) override
	Notify prefetcher of cache access (may be any access or just misses, depending on cache parameters.)
void	insert (const PacketPtr &pkt, PrefetchInfo &new_pfi, int32_t priority)
virtual void	calculatePrefetch (const PrefetchInfo &pfi, std::vector< AddrPriority > &addresses)=0
PacketPtr	getPacket () override
Tick	nextPrefetchReadyTime () const override
void	printQueue (const std::list< DeferredPacket > &queue) const
Public Member Functions inherited from gem5::prefetch::Base
	Base (const BasePrefetcherParams &p)
virtual	~Base ()=default
virtual void	setCache (BaseCache *_cache)
virtual void	notify (const PacketPtr &pkt, const PrefetchInfo &pfi)=0
	Notify prefetcher of cache access (may be any access or just misses, depending on cache parameters.)
virtual void	notifyFill (const PacketPtr &pkt)
	Notify prefetcher of cache fill.
virtual PacketPtr	getPacket ()=0
virtual Tick	nextPrefetchReadyTime () const =0
void	prefetchUnused ()
void	incrDemandMhsrMisses ()
void	pfHitInCache ()
void	pfHitInMSHR ()
void	pfHitInWB ()
void	regProbeListeners () override
	Register probe points for this object.
void	probeNotify (const PacketPtr &pkt, bool miss)
	Process a notification event from the ProbeListener.
void	addEventProbe (SimObject *obj, const char *name)
	Add a SimObject and a probe name to listen events from.
void	addMMU (BaseMMU *mmu)
	Add a BaseMMU object to be used whenever a translation is needed.
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	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 ()
virtual void	serialize (CheckpointOut &cp) const =0
	Serialize an object.
virtual void	unserialize (CheckpointIn &cp)=0
	Unserialize an object.
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 (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

Private Types
using	HistoryBuffer = CircularQueue< CompactorEntry >
	History buffer is a circular buffer that stores the sequence of retired instructions in FIFO order.

Private Member Functions
void	notifyRetiredInst (const Addr pc)
	Updates the prefetcher structures upon an instruction retired.

Private Attributes
const unsigned int	precSize
	Number of preceding and subsequent spatial addresses to compact.
const unsigned int	succSize
const unsigned int	maxCompactorEntries
	Number of entries used for the temporal compactor.
CompactorEntry	spatialCompactor
std::deque< CompactorEntry >	temporalCompactor
HistoryBuffer	historyBuffer
AssociativeSet< IndexEntry >	index
	The index table is a small cache-like structure that facilitates fast search of the history buffer.
CircularQueue< HistoryBuffer::iterator >	streamAddressBuffer
	A Stream Address Buffer (SAB) tracks a window of consecutive spatial regions.
std::vector< PrefetchListenerPC * >	listenersPC
	Array of probe listeners.

Additional Inherited Members
Public Types inherited from gem5::prefetch::Queued
using	AddrPriority = std::pair< Addr, int32_t >
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::ClockedObject
PowerState *	powerState
Protected Types inherited from gem5::prefetch::Queued
using	const_iterator = std::list< DeferredPacket >::const_iterator
using	iterator = std::list< DeferredPacket >::iterator
Protected Member Functions inherited from gem5::prefetch::Base
bool	observeAccess (const PacketPtr &pkt, bool miss) const
	Determine if this access should be observed.
bool	inCache (Addr addr, bool is_secure) const
	Determine if address is in cache.
bool	inMissQueue (Addr addr, bool is_secure) const
	Determine if address is in cache miss queue.
bool	hasBeenPrefetched (Addr addr, bool is_secure) const
bool	samePage (Addr a, Addr b) const
	Determine if addresses are on the same page.
Addr	blockAddress (Addr a) const
	Determine the address of the block in which a lays.
Addr	blockIndex (Addr a) const
	Determine the address of a at block granularity.
Addr	pageAddress (Addr a) const
	Determine the address of the page in which a lays.
Addr	pageOffset (Addr a) const
	Determine the page-offset of a
Addr	pageIthBlockAddress (Addr page, uint32_t i) const
	Build the address of the i-th block inside the page.
Protected Member Functions inherited from gem5::Drainable
	Drainable ()
virtual	~Drainable ()
virtual DrainState	drain ()=0
	Draining is the process of clearing out the states of SimObjects.These are the SimObjects that are partially executed or are partially in flight.
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 inherited from gem5::prefetch::Queued
std::list< DeferredPacket >	pfq
std::list< DeferredPacket >	pfqMissingTranslation
const unsigned	queueSize
	Maximum size of the prefetch queue.
const unsigned	missingTranslationQueueSize
	Maximum size of the queue holding prefetch requests with missing address translations.
const Cycles	latency
	Cycles after generation when a prefetch can first be issued.
const bool	queueSquash
	Squash queued prefetch if demand access observed.
const bool	queueFilter
	Filter prefetches if already queued.
const bool	cacheSnoop
	Snoop the cache before generating prefetch (cheating basically)
const bool	tagPrefetch
	Tag prefetch with PC of generating access?
const unsigned int	throttleControlPct
	Percentage of requests that can be throttled.
gem5::prefetch::Queued::QueuedStats	statsQueued
Protected Attributes inherited from gem5::prefetch::Base
BaseCache *	cache
	Pointr to the parent cache.
unsigned	blkSize
	The block size of the parent cache.
unsigned	lBlkSize
	log_2(block size of the parent cache).
const bool	onMiss
	Only consult prefetcher on cache misses?
const bool	onRead
	Consult prefetcher on reads?
const bool	onWrite
	Consult prefetcher on reads?
const bool	onData
	Consult prefetcher on data accesses?
const bool	onInst
	Consult prefetcher on instruction accesses?
const RequestorID	requestorId
	Request id for prefetches.
const Addr	pageBytes
const bool	prefetchOnAccess
	Prefetch on every access, not just misses.
const bool	prefetchOnPfHit
	Prefetch on hit on prefetched lines.
const bool	useVirtualAddresses
	Use Virtual Addresses for prefetching.
gem5::prefetch::Base::StatGroup	prefetchStats
uint64_t	issuedPrefetches
	Total prefetches issued.
uint64_t	usefulPrefetches
	Total prefetches that has been useful.
BaseMMU *	mmu
	Registered mmu for address translations.
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 55 of file pif.hh.

Member Typedef Documentation

HistoryBuffer

using gem5::prefetch::PIF::HistoryBuffer = CircularQueue<CompactorEntry>

private

History buffer is a circular buffer that stores the sequence of retired instructions in FIFO order.

Definition at line 134 of file pif.hh.

Constructor & Destructor Documentation

PIF()

gem5::prefetch::PIF::PIF

(

const PIFPrefetcherParams &

p

)

Definition at line 43 of file pif.cc.

~PIF()

gem5::prefetch::PIF::~PIF ( )

default

Member Function Documentation

addEventProbeRetiredInsts()

void gem5::prefetch::PIF::addEventProbeRetiredInsts	(	SimObject *	obj,
		const char *	name
	)

Add a SimObject and a probe name to monitor the retired instructions.

Parameters

obj	The SimObject pointer to listen from
name	The probe name

Definition at line 244 of file pif.cc.

References gem5::SimObject::getProbeManager(), listenersPC, and gem5::Named::name().

calculatePrefetch()

void gem5::prefetch::PIF::calculatePrefetch ( const PrefetchInfo &  pfi, std::vector< AddrPriority > &  addresses  )

virtual

Implements gem5::prefetch::Queued.

Definition at line 200 of file pif.cc.

References gem5::prefetch::Base::PrefetchInfo::getPC(), gem5::prefetch::Base::PrefetchInfo::hasPC(), gem5::prefetch::PIF::IndexEntry::historyIt, index, gem5::prefetch::Base::lBlkSize, gem5::MipsISA::pc, gem5::CircularQueue< T >::push_back(), and streamAddressBuffer.

notifyRetiredInst()

void gem5::prefetch::PIF::notifyRetiredInst ( const Addr  pc )

private

Updates the prefetcher structures upon an instruction retired.

Parameters

pc	PC of the instruction being retired

Definition at line 136 of file pif.cc.

References gem5::CircularQueue< T >::getIterator(), historyBuffer, gem5::prefetch::PIF::IndexEntry::historyIt, index, gem5::prefetch::PIF::CompactorEntry::inSameSpatialRegion(), gem5::prefetch::Base::lBlkSize, maxCompactorEntries, gem5::MipsISA::pc, precSize, gem5::CircularQueue< T >::push_back(), spatialCompactor, succSize, gem5::CircularQueue< T >::tail(), temporalCompactor, and gem5::prefetch::PIF::CompactorEntry::trigger.

Member Data Documentation

historyBuffer

HistoryBuffer gem5::prefetch::PIF::historyBuffer

private

Definition at line 135 of file pif.hh.

Referenced by notifyRetiredInst().

index

AssociativeSet<IndexEntry> gem5::prefetch::PIF::index

private

The index table is a small cache-like structure that facilitates fast search of the history buffer.

Definition at line 145 of file pif.hh.

Referenced by calculatePrefetch(), and notifyRetiredInst().

listenersPC

std::vector<PrefetchListenerPC *> gem5::prefetch::PIF::listenersPC

private

Array of probe listeners.

Definition at line 177 of file pif.hh.

Referenced by addEventProbeRetiredInsts().

maxCompactorEntries

const unsigned int gem5::prefetch::PIF::maxCompactorEntries

private

Number of entries used for the temporal compactor.

Definition at line 62 of file pif.hh.

Referenced by notifyRetiredInst().

precSize

const unsigned int gem5::prefetch::PIF::precSize

private

Number of preceding and subsequent spatial addresses to compact.

Definition at line 59 of file pif.hh.

Referenced by notifyRetiredInst().

spatialCompactor

CompactorEntry gem5::prefetch::PIF::spatialCompactor

private

Definition at line 127 of file pif.hh.

Referenced by notifyRetiredInst().

streamAddressBuffer

CircularQueue<HistoryBuffer::iterator> gem5::prefetch::PIF::streamAddressBuffer

private

A Stream Address Buffer (SAB) tracks a window of consecutive spatial regions.

The SAB mantains a pointer to the sequence in the history buffer, initiallly set to the pointer taken from the index table

Definition at line 153 of file pif.hh.

Referenced by calculatePrefetch().

succSize

const unsigned int gem5::prefetch::PIF::succSize

private

Definition at line 60 of file pif.hh.

Referenced by notifyRetiredInst().

temporalCompactor

std::deque<CompactorEntry> gem5::prefetch::PIF::temporalCompactor

private

Definition at line 128 of file pif.hh.

Referenced by notifyRetiredInst().

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

• mem/cache/prefetch/pif.hh
• mem/cache/prefetch/pif.cc