#include <bop.hh>

Inheritance diagram for gem5::prefetch::BOP:

Classes
struct	DelayQueueEntry
	In a first implementation of the BO prefetcher, both banks of the RR were written simultaneously when a prefetched line is inserted into the cache. More...

Public Member Functions
	BOP (const BOPPrefetcherParams &p)

	~BOP ()=default

void	calculatePrefetch (const PrefetchInfo &pfi, std::vector< AddrPriority > &addresses, const CacheAccessor &cache) override

Public Member Functions inherited from gem5::prefetch::Queued
	Queued (const QueuedPrefetcherParams &p)

virtual	~Queued ()

void	notify (const CacheAccessProbeArg &acc, 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, const CacheAccessor &cache)

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	setParentInfo (System sys, ProbeManager pm, unsigned blk_size)

virtual void	notifyEvict (const EvictionInfo &info)
	Notify prefetcher of cache eviction.

void	prefetchUnused ()

void	incrDemandMhsrMisses ()

void	pfHitInCache ()

void	pfHitInMSHR ()

void	pfHitInWB ()

void	regProbeListeners () override
	Register probe points for this object.

void	probeNotify (const CacheAccessProbeArg &acc, 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.

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

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
enum	RRWay { Left , Right }

typedef std::pair< int16_t, uint8_t >	OffsetListEntry
	Structure to save the offset and the score.

Private Member Functions
void	delayQueueEventWrapper ()
	Event to handle the delay queue processing.

unsigned int	hash (Addr addr, unsigned int way) const
	Generate a hash for the specified address to index the RR table.

void	insertIntoRR (Addr addr, unsigned int way)
	Insert the specified address into the RR table.

void	insertIntoDelayQueue (Addr addr)
	Insert the specified address into the delay queue.

void	resetScores ()
	Reset all the scores from the offset list.

Addr	tag (Addr addr) const
	Generate the tag for the specified address based on the tag bits and the block size.

bool	testRR (Addr) const
	Test if @X-O is hitting in the RR table to update the offset score.

void	bestOffsetLearning (Addr)
	Learning phase of the BOP.

void	notifyFill (const CacheAccessProbeArg &arg) override
	Update the RR right table after a prefetch fill.

Private Attributes
const unsigned int	scoreMax
	Learning phase parameters.

const unsigned int	roundMax

const unsigned int	badScore

const unsigned int	rrEntries
	Recent requests table parameteres.

const unsigned int	tagMask

const bool	delayQueueEnabled
	Delay queue parameters.

const unsigned int	delayQueueSize

const unsigned int	delayTicks

std::vector< Addr >	rrLeft

std::vector< Addr >	rrRight

std::vector< OffsetListEntry >	offsetsList

std::deque< DelayQueueEntry >	delayQueue

EventFunctionWrapper	delayQueueEvent

bool	issuePrefetchRequests
	Hardware prefetcher enabled.

Addr	bestOffset
	Current best offset to issue prefetches.

Addr	phaseBestOffset
	Current best offset found in the learning phase.

std::vector< OffsetListEntry >::iterator	offsetsListIterator
	Current test offset index.

unsigned int	bestScore
	Max score found so far.

unsigned int	round
	Current round.

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, bool prefetched) const
	Determine if this access should be observed.

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 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
System *	system
	Pointer to the parent system.

ProbeManager *	probeManager
	Pointer to the parent cache's probe manager.

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 52 of file bop.hh.

Member Typedef Documentation

◆ OffsetListEntry

typedef std::pair<int16_t, uint8_t> gem5::prefetch::BOP::OffsetListEntry

private

Structure to save the offset and the score.

Definition at line 78 of file bop.hh.

Member Enumeration Documentation

◆ RRWay

enum gem5::prefetch::BOP::RRWay

private

Enumerator
Left
Right

Definition at line 56 of file bop.hh.

Constructor & Destructor Documentation

◆ BOP()

gem5::prefetch::BOP::BOP ( const BOPPrefetcherParams & p )

Definition at line 40 of file bop.cc.

References delayQueueEventWrapper().

◆ ~BOP()

gem5::prefetch::BOP::~BOP ( )

default

Member Function Documentation

◆ bestOffsetLearning()

void gem5::prefetch::BOP::bestOffsetLearning ( Addr x )

private

Learning phase of the BOP.

Update the intermediate values of the round and update the best offset if found

Definition at line 188 of file bop.cc.

References badScore, bestOffset, bestScore, DPRINTF, issuePrefetchRequests, offsetsList, offsetsListIterator, phaseBestOffset, resetScores(), round, roundMax, scoreMax, testRR(), and gem5::RiscvISA::x.

Referenced by calculatePrefetch().

◆ calculatePrefetch()

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

overridevirtual

Implements gem5::prefetch::Queued.

Definition at line 229 of file bop.cc.

References gem5::X86ISA::addr, bestOffset, bestOffsetLearning(), delayQueueEnabled, DPRINTF, gem5::prefetch::Base::PrefetchInfo::getAddr(), insertIntoDelayQueue(), insertIntoRR(), issuePrefetchRequests, gem5::prefetch::Base::lBlkSize, Left, and tag().

◆ delayQueueEventWrapper()

void gem5::prefetch::BOP::delayQueueEventWrapper ( )

private

Event to handle the delay queue processing.

Definition at line 100 of file bop.cc.

References gem5::curTick(), delayQueue, delayQueueEvent, insertIntoRR(), Left, and gem5::EventManager::schedule().

Referenced by BOP().

◆ hash()

unsigned int gem5::prefetch::BOP::hash	(	Addr	addr,
		unsigned int	way ) const

private

Generate a hash for the specified address to index the RR table.

Parameters

addr	address to hash
way	RR table to which is addressed (left/right)

Definition at line 117 of file bop.cc.

References gem5::X86ISA::addr, gem5::floorLog2(), and rrEntries.

Referenced by insertIntoRR().

◆ insertIntoDelayQueue()

void gem5::prefetch::BOP::insertIntoDelayQueue ( Addr addr )

private

Insert the specified address into the delay queue.

This will trigger an event after the delay cycles pass

Parameters

addr	address to insert into the delay queue

Definition at line 138 of file bop.cc.

References gem5::curTick(), delayQueue, delayQueueEvent, delayQueueSize, delayTicks, gem5::EventManager::schedule(), gem5::Event::scheduled(), and gem5::RiscvISA::x.

Referenced by calculatePrefetch().

◆ insertIntoRR()

void gem5::prefetch::BOP::insertIntoRR	(	Addr	addr,
		unsigned int	way )

private

Insert the specified address into the RR table.

Parameters

addr	address to insert
way	RR table to which the address will be inserted

Definition at line 125 of file bop.cc.

References gem5::X86ISA::addr, hash(), Left, Right, rrLeft, and rrRight.

Referenced by calculatePrefetch(), delayQueueEventWrapper(), and notifyFill().

◆ notifyFill()

void gem5::prefetch::BOP::notifyFill ( const CacheAccessProbeArg & arg )

overrideprivatevirtual

Update the RR right table after a prefetch fill.

Reimplemented from gem5::prefetch::Base.

Definition at line 256 of file bop.cc.

References bestOffset, gem5::Packet::cmd, gem5::Packet::getAddr(), insertIntoRR(), gem5::MemCmd::isHWPrefetch(), issuePrefetchRequests, gem5::CacheAccessProbeArg::pkt, Right, and tag().

◆ resetScores()

void gem5::prefetch::BOP::resetScores ( )

private

Reset all the scores from the offset list.

Definition at line 156 of file bop.cc.

References offsetsList.

Referenced by bestOffsetLearning().

◆ tag()

Addr gem5::prefetch::BOP::tag ( Addr addr ) const

inlineprivate

Generate the tag for the specified address based on the tag bits and the block size.

Parameters

addr	address to get the tag from

Definition at line 164 of file bop.cc.

References gem5::X86ISA::addr, gem5::prefetch::Base::blkSize, and tagMask.

Referenced by calculatePrefetch(), and notifyFill().

◆ testRR()

bool gem5::prefetch::BOP::testRR ( Addr addr ) const

private

Test if @X-O is hitting in the RR table to update the offset score.

Definition at line 170 of file bop.cc.

References gem5::X86ISA::addr, rrLeft, and rrRight.

Referenced by bestOffsetLearning().

Member Data Documentation

◆ badScore

const unsigned int gem5::prefetch::BOP::badScore

private

Definition at line 65 of file bop.hh.

Referenced by bestOffsetLearning().

◆ bestOffset

Addr gem5::prefetch::BOP::bestOffset

private

Current best offset to issue prefetches.

Definition at line 105 of file bop.hh.

Referenced by bestOffsetLearning(), calculatePrefetch(), and notifyFill().

◆ bestScore

unsigned int gem5::prefetch::BOP::bestScore

private

Max score found so far.

Definition at line 111 of file bop.hh.

Referenced by bestOffsetLearning().

◆ delayQueue

std::deque<DelayQueueEntry> gem5::prefetch::BOP::delayQueue

private

Definition at line 96 of file bop.hh.

Referenced by delayQueueEventWrapper(), and insertIntoDelayQueue().

◆ delayQueueEnabled

const bool gem5::prefetch::BOP::delayQueueEnabled

private

Delay queue parameters.

Definition at line 70 of file bop.hh.

Referenced by calculatePrefetch().

◆ delayQueueEvent

EventFunctionWrapper gem5::prefetch::BOP::delayQueueEvent

private

Definition at line 100 of file bop.hh.

Referenced by delayQueueEventWrapper(), and insertIntoDelayQueue().

◆ delayQueueSize

const unsigned int gem5::prefetch::BOP::delayQueueSize

private

Definition at line 71 of file bop.hh.

Referenced by insertIntoDelayQueue().

◆ delayTicks

const unsigned int gem5::prefetch::BOP::delayTicks

private

Definition at line 72 of file bop.hh.

Referenced by insertIntoDelayQueue().

◆ issuePrefetchRequests

bool gem5::prefetch::BOP::issuePrefetchRequests

private

Hardware prefetcher enabled.

Definition at line 103 of file bop.hh.

Referenced by bestOffsetLearning(), calculatePrefetch(), and notifyFill().

◆ offsetsList

std::vector<OffsetListEntry> gem5::prefetch::BOP::offsetsList

private

Definition at line 79 of file bop.hh.

Referenced by bestOffsetLearning(), and resetScores().

◆ offsetsListIterator

std::vector<OffsetListEntry>::iterator gem5::prefetch::BOP::offsetsListIterator

private

Current test offset index.

Definition at line 109 of file bop.hh.

Referenced by bestOffsetLearning().

◆ phaseBestOffset

Addr gem5::prefetch::BOP::phaseBestOffset

private

Current best offset found in the learning phase.

Definition at line 107 of file bop.hh.

Referenced by bestOffsetLearning().

◆ round

unsigned int gem5::prefetch::BOP::round

private

Current round.

Definition at line 113 of file bop.hh.

Referenced by bestOffsetLearning().

◆ roundMax

const unsigned int gem5::prefetch::BOP::roundMax

private

Definition at line 64 of file bop.hh.

Referenced by bestOffsetLearning().

◆ rrEntries

const unsigned int gem5::prefetch::BOP::rrEntries

private

Recent requests table parameteres.

Definition at line 67 of file bop.hh.

Referenced by hash().

◆ rrLeft

std::vector<Addr> gem5::prefetch::BOP::rrLeft

private

Definition at line 74 of file bop.hh.

Referenced by insertIntoRR(), and testRR().

◆ rrRight

std::vector<Addr> gem5::prefetch::BOP::rrRight

private

Definition at line 75 of file bop.hh.

Referenced by insertIntoRR(), and testRR().

◆ scoreMax

const unsigned int gem5::prefetch::BOP::scoreMax

private

Learning phase parameters.

Definition at line 63 of file bop.hh.

Referenced by bestOffsetLearning().

◆ tagMask

const unsigned int gem5::prefetch::BOP::tagMask

private

Definition at line 68 of file bop.hh.

Referenced by tag().

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

mem/cache/prefetch/bop.hh
mem/cache/prefetch/bop.cc

Classes

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ OffsetListEntry

Member Enumeration Documentation

◆ RRWay

Constructor & Destructor Documentation

◆ BOP()

◆ ~BOP()

Member Function Documentation

◆ bestOffsetLearning()

◆ calculatePrefetch()

◆ delayQueueEventWrapper()

◆ hash()

◆ insertIntoDelayQueue()

◆ insertIntoRR()

◆ notifyFill()

◆ resetScores()

◆ tag()

◆ testRR()

Member Data Documentation

◆ badScore

◆ bestOffset

◆ bestScore

◆ delayQueue

◆ delayQueueEnabled

◆ delayQueueEvent

◆ delayQueueSize

◆ delayTicks

◆ issuePrefetchRequests

◆ offsetsList

◆ offsetsListIterator

◆ phaseBestOffset

◆ round

◆ roundMax

◆ rrEntries

◆ rrLeft

◆ rrRight

◆ scoreMax

◆ tagMask