#include <access_map_pattern_matching.hh>

Inheritance diagram for AccessMapPatternMatching:

Classes
struct	AccessMapEntry
	AccessMapEntry data type. More...

Public Member Functions
	AccessMapPatternMatching (const AccessMapPatternMatchingParams *p)
	Copyright (c) 2018 Metempsy Technology Consulting All rights reserved. More...

	~AccessMapPatternMatching ()

void	startup () override
	startup() is the final initialization call before simulation. More...

void	calculatePrefetch (const BasePrefetcher::PrefetchInfo &pfi, std::vector< QueuedPrefetcher::AddrPriority > &addresses)

Public Member Functions inherited from ClockedObject
	ClockedObject (const ClockedObjectParams *p)

const Params *	params () const

void	serialize (CheckpointOut &cp) const override
	Serialize an object. More...

void	unserialize (CheckpointIn &cp) override
	Unserialize an object. More...

Enums::PwrState	pwrState () const

std::string	pwrStateName () const

std::vector< double >	pwrStateWeights () const
	Returns the percentage residency for each power state. More...

void	computeStats ()
	Record stats values like state residency by computing the time difference from previous update. More...

void	pwrState (Enums::PwrState)

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...

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...

Public Member Functions inherited from Clocked
void	updateClockPeriod ()
	Update the tick to the current tick. More...

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. More...

Cycles	curCycle () const
	Determine the current cycle, corresponding to a tick aligned to a clock edge. More...

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. More...

uint64_t	frequency () const

Tick	clockPeriod () const

double	voltage () const

Cycles	ticksToCycles (Tick t) const

Tick	cyclesToTicks (Cycles c) const

Private Types
enum	AccessMapState { AM_INIT, AM_PREFETCH, AM_ACCESS, AM_INVALID }
	Data type representing the state of a cacheline in the access map. More...

Private Member Functions
bool	checkCandidate (std::vector< AccessMapState > const &states, Addr current, int stride) const
	Given a target cacheline, this function checks if the cachelines that follow the provided stride have been accessed. More...

AccessMapEntry *	getAccessMapEntry (Addr am_addr, bool is_secure)
	Obtain an AccessMapEntry from the AccessMapTable, if the entry is not found a new one is initialized and inserted. More...

void	setEntryState (AccessMapEntry &entry, Addr block, enum AccessMapState state)
	Updates the state of a block within an AccessMapEntry, also updates the prefetcher metrics. More...

void	processEpochEvent ()
	This event constitues the epoch of the statistics that keep track of the prefetcher accuracy, when this event triggers, the prefetcher degree is adjusted and the statistics counters are reset. More...

Private Attributes
const unsigned	blkSize
	Cacheline size used by the prefetcher using this object. More...

const unsigned	limitStride
	Limit the stride checking to -limitStride/+limitStride. More...

const unsigned	startDegree
	Maximum number of prefetch generated. More...

const uint64_t	hotZoneSize
	Amount of memory covered by a hot zone. More...

const double	highCoverageThreshold
	A prefetch coverage factor bigger than this is considered high. More...

const double	lowCoverageThreshold
	A prefetch coverage factor smaller than this is considered low. More...

const double	highAccuracyThreshold
	A prefetch accuracy factor bigger than this is considered high. More...

const double	lowAccuracyThreshold
	A prefetch accuracy factor smaller than this is considered low. More...

const double	highCacheHitThreshold
	A cache hit ratio bigger than this is considered high. More...

const double	lowCacheHitThreshold
	A cache hit ratio smaller than this is considered low. More...

const Cycles	epochCycles
	Cycles in an epoch period. More...

const Tick	offChipMemoryLatency
	Off chip memory latency to use for the epoch bandwidth calculation. More...

AssociativeSet< AccessMapEntry >	accessMapTable
	Access map table. More...

uint64_t	numGoodPrefetches
	Number of good prefetches. More...

uint64_t	numTotalPrefetches
	Number of prefetches issued. More...

uint64_t	numRawCacheMisses
	Number of raw cache misses. More...

uint64_t	numRawCacheHits
	Number of raw cache hits. More...

unsigned	degree
	Current degree. More...

unsigned	usefulDegree
	Current useful degree. More...

EventFunctionWrapper	epochEvent

Additional Inherited Members
Public Types inherited from ClockedObject
typedef ClockedObjectParams	Params
	Parameters of ClockedObject. More...

Public Types inherited from SimObject
typedef SimObjectParams	Params

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 Member Functions inherited from Clocked
	Clocked (ClockDomain &clk_domain)
	Create a clocked object and set the clock domain based on the parameters. More...

	Clocked (Clocked &)=delete

Clocked &	operator= (Clocked &)=delete

virtual	~Clocked ()
	Virtual destructor due to inheritance. More...

void	resetClock () const
	Reset the object's clock using the current global tick value. More...

virtual void	clockPeriodUpdated ()
	A hook subclasses can implement so they can do any extra work that's needed when the clock rate is changed. More...

Protected Attributes inherited from ClockedObject
Enums::PwrState	_currPwrState
	To keep track of the current power state. More...

Tick	prvEvalTick

ClockedObject::ClockedObjectStats	stats

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

Definition at line 50 of file access_map_pattern_matching.hh.

Member Enumeration Documentation

◆ AccessMapState

enum AccessMapPatternMatching::AccessMapState

private

Data type representing the state of a cacheline in the access map.

Enumerator
AM_INIT
AM_PREFETCH
AM_ACCESS
AM_INVALID

Definition at line 78 of file access_map_pattern_matching.hh.

Constructor & Destructor Documentation

◆ AccessMapPatternMatching()

AccessMapPatternMatching::AccessMapPatternMatching ( const AccessMapPatternMatchingParams * p )

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer; redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution; neither the name of the copyright holders nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Authors: Javier Bueno

Definition at line 38 of file access_map_pattern_matching.cc.

References fatal_if, hotZoneSize, isPowerOf2(), SimObject::name(), and processEpochEvent().

Referenced by calculatePrefetch().

◆ ~AccessMapPatternMatching()

AccessMapPatternMatching::~AccessMapPatternMatching ( )

inline

Definition at line 184 of file access_map_pattern_matching.hh.

References calculatePrefetch(), and startup().

Member Function Documentation

◆ calculatePrefetch()

void AccessMapPatternMatching::calculatePrefetch	(	const BasePrefetcher::PrefetchInfo &	pfi,
		std::vector< QueuedPrefetcher::AddrPriority > &	addresses
	)

Create a contiguous copy of the 3 entries states. With this, we avoid doing boundaries checking in the loop that looks for prefetch candidates, mark out of range positions with AM_INVALID

am_entry_prev->states => states[ 0 .. lines_per_zone-1] am_entry_curr->states => states[ lines_per_zone .. 2*lines_per_zone-1] am_entry_next->states => states[2*lines_per_zone .. 3*lines_per_zone-1]

Definition at line 154 of file access_map_pattern_matching.cc.

References AccessMapPatternMatching(), AM_ACCESS, AM_INVALID, AM_PREFETCH, blkSize, checkCandidate(), degree, getAccessMapEntry(), BasePrefetcher::PrefetchInfo::getAddr(), hotZoneSize, BasePrefetcher::PrefetchInfo::isSecure(), limitStride, MaxAddr, setEntryState(), AccessMapPatternMatching::AccessMapEntry::states, and ArmISA::stride.

Referenced by SlimAMPMPrefetcher::calculatePrefetch(), AMPMPrefetcher::calculatePrefetch(), ~AccessMapPatternMatching(), and AMPMPrefetcher::~AMPMPrefetcher().

◆ checkCandidate()

bool AccessMapPatternMatching::checkCandidate	(	std::vector< AccessMapState > const &	states,
		Addr	current,
		int	stride
	)		const

inlineprivate

Given a target cacheline, this function checks if the cachelines that follow the provided stride have been accessed.

If so, the line is considered a good candidate.

Parameters

states	vector containing the states of three contiguous hot zones
current	target block (cacheline)
stride	access stride to obtain the reference cachelines

Returns: true if current is a prefetch candidate

Definition at line 143 of file access_map_pattern_matching.hh.

References AM_ACCESS, AM_INVALID, getAccessMapEntry(), processEpochEvent(), ArmISA::s, setEntryState(), and ArmISA::stride.

Referenced by calculatePrefetch().

◆ getAccessMapEntry()

AccessMapPatternMatching::AccessMapEntry * AccessMapPatternMatching::getAccessMapEntry	(	Addr	am_addr,
		bool	is_secure
	)

private

Obtain an AccessMapEntry from the AccessMapTable, if the entry is not found a new one is initialized and inserted.

Parameters

am_addr	address of the hot zone
is_secure	whether the address belongs to the secure memory area

Returns: the corresponding entry

Definition at line 103 of file access_map_pattern_matching.cc.

References accessMapTable.

Referenced by calculatePrefetch(), and checkCandidate().

◆ processEpochEvent()

void AccessMapPatternMatching::processEpochEvent ( )

private

This event constitues the epoch of the statistics that keep track of the prefetcher accuracy, when this event triggers, the prefetcher degree is adjusted and the statistics counters are reset.

Definition at line 69 of file access_map_pattern_matching.cc.

References Clocked::clockEdge(), degree, epochCycles, epochEvent, highAccuracyThreshold, highCacheHitThreshold, highCoverageThreshold, lowAccuracyThreshold, lowCacheHitThreshold, lowCoverageThreshold, numGoodPrefetches, numRawCacheHits, numRawCacheMisses, numTotalPrefetches, offChipMemoryLatency, EventManager::schedule(), and usefulDegree.

Referenced by AccessMapPatternMatching(), and checkCandidate().

◆ setEntryState()

void AccessMapPatternMatching::setEntryState	(	AccessMapEntry &	entry,
		Addr	block,
		enum AccessMapState	state
	)

private

Updates the state of a block within an AccessMapEntry, also updates the prefetcher metrics.

Parameters

entry	AccessMapEntry to update
block	cacheline within the hot zone
state	new state

Definition at line 119 of file access_map_pattern_matching.cc.

References AM_ACCESS, AM_INIT, AM_PREFETCH, numGoodPrefetches, numRawCacheHits, numRawCacheMisses, numTotalPrefetches, panic, and AccessMapPatternMatching::AccessMapEntry::states.

Referenced by calculatePrefetch(), and checkCandidate().

◆ startup()

void AccessMapPatternMatching::startup ( )

overridevirtual

startup() is the final initialization call before simulation.

All state is initialized (including unserialized state, if any, such as the curTick() value), so this is the appropriate place to schedule initial event(s) for objects that need them.

Reimplemented from SimObject.

Definition at line 63 of file access_map_pattern_matching.cc.

References Clocked::clockEdge(), epochCycles, epochEvent, and EventManager::schedule().

Referenced by ~AccessMapPatternMatching().