#include <multi.hh>

Inheritance diagram for gem5::compression::Multi:

Classes
class	MultiCompData

struct	MultiStats

Public Types
typedef MultiCompressorParams	Params

Public Types inherited from gem5::compression::Base
typedef BaseCacheCompressorParams	Params

Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params

Public Member Functions
	Multi (const Params &p)

	~Multi ()

void	setCache (BaseCache *_cache) override
	The cache can only be set once.

std::unique_ptr< Base::CompressionData >	compress (const std::vector< Base::Chunk > &chunks, Cycles &comp_lat, Cycles &decomp_lat) override
	Apply the compression process to the cache line.

void	decompress (const CompressionData comp_data, uint64_t data) override
	Apply the decompression process to the compressed data.

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

virtual	~Base ()=default

std::unique_ptr< CompressionData >	compress (const uint64_t *data, Cycles &comp_lat, Cycles &decomp_lat)
	Apply the compression process to the cache line.

Cycles	getDecompressionLatency (const CacheBlk *blk)
	Get the decompression latency if the block is compressed.

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

Protected Attributes
std::vector< Base * >	compressors
	List of sub-compressors.

const std::size_t	numEncodingBits
	An encoding is associated to each sub-compressor to inform which sub-compressor to use when decompressing data.

const Cycles	extraDecompressionLatency
	Extra decompression latency to be added to the sub-compressor's decompression latency.

gem5::compression::Multi::MultiStats	multiStats

Protected Attributes inherited from gem5::compression::Base
const std::size_t	blkSize
	Uncompressed cache line size (in bytes).

const unsigned	chunkSizeBits
	Chunk size, in number of bits.

const std::size_t	sizeThreshold
	Size in bytes at which a compression is classified as bad and therefore the compressed block is restored to its uncompressed format.

const Cycles	compChunksPerCycle
	Degree of parallelization of the compression process.

const Cycles	compExtraLatency
	Extra latency added to compression due to packaging, shifting or other operations.

const Cycles	decompChunksPerCycle
	Degree of parallelization of the decompression process.

const Cycles	decompExtraLatency
	Extra latency added to decompression due to packaging, shifting or other operations.

BaseCache *	cache
	Pointer to the parent cache.

gem5::compression::Base::BaseStats	stats

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.

Additional Inherited Members
Static Public Member Functions inherited from gem5::compression::Base
static void	setDecompressionLatency (CacheBlk *blk, const Cycles lat)
	Set the decompression latency of compressed block.

static void	setSizeBits (CacheBlk *blk, const std::size_t size_bits)
	Set the size of the compressed block, in bits.

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 Types inherited from gem5::compression::Base
typedef uint64_t	Chunk
	A chunk is a basic lexical unit.

Protected Member Functions inherited from gem5::compression::Base
std::vector< Chunk >	toChunks (const uint64_t *data) const
	This function splits the raw data into chunks, so that it can be parsed by the compressor.

void	fromChunks (const std::vector< Chunk > &chunks, uint64_t *data) const
	This function re-joins the chunks to recreate the original data.

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.

Detailed Description

Definition at line 52 of file multi.hh.

Member Typedef Documentation

◆ Params

typedef MultiCompressorParams gem5::compression::Multi::Params

Definition at line 104 of file multi.hh.

Constructor & Destructor Documentation

◆ Multi()

gem5::compression::Multi::Multi ( const Params & p )

Definition at line 64 of file multi.cc.

References compressors, and fatal_if.

◆ ~Multi()

gem5::compression::Multi::~Multi ( )

Definition at line 73 of file multi.cc.

References compressors.

Member Function Documentation

◆ compress()

std::unique_ptr< Base::CompressionData > gem5::compression::Multi::compress	(	const std::vector< Base::Chunk > &	chunks,
		Cycles &	comp_lat,
		Cycles &	decomp_lat )

overridevirtual

Apply the compression process to the cache line.

Returns the number of cycles used by the compressor, however it is usually covered by a good pipelined execution, and is currently ignored. The decompression latency is also returned, in order to avoid increasing simulation time and memory consumption.

Parameters

chunks	The cache line to be compressed, divided into chunks.
comp_lat	Compression latency in number of cycles.
decomp_lat	Decompression latency in number of cycles.

Returns: Cache line after compression.

Implements gem5::compression::Base.

Definition at line 90 of file multi.cc.

References gem5::alignToPowerOfTwo(), gem5::compression::Base::blkSize, gem5::compression::Base::compExtraLatency, compressors, data, gem5::compression::Base::decompExtraLatency, DPRINTF, gem5::compression::Base::fromChunks(), gem5::ArmISA::i, gem5::MipsISA::index, multiStats, numEncodingBits, and gem5::compression::Multi::MultiStats::ranks.

◆ decompress()

void gem5::compression::Multi::decompress	(	const CompressionData *	comp_data,
		uint64_t *	cache_line )

overridevirtual

Apply the decompression process to the compressed data.

Parameters

comp_data	Compressed cache line.
cache_line	The cache line to be decompressed.

Implements gem5::compression::Base.

Definition at line 184 of file multi.cc.

References gem5::compression::Multi::MultiCompData::compData, compressors, and gem5::compression::Multi::MultiCompData::getIndex().

◆ setCache()

void gem5::compression::Multi::setCache ( BaseCache * _cache )

overridevirtual

The cache can only be set once.

Reimplemented from gem5::compression::Base.

Definition at line 81 of file multi.cc.

References compressors, and gem5::compression::Base::setCache().

Member Data Documentation

◆ compressors

std::vector<Base*> gem5::compression::Multi::compressors

protected

List of sub-compressors.

Definition at line 63 of file multi.hh.

Referenced by compress(), decompress(), Multi(), setCache(), and ~Multi().

◆ extraDecompressionLatency

const Cycles gem5::compression::Multi::extraDecompressionLatency

protected

Extra decompression latency to be added to the sub-compressor's decompression latency.

This can different from zero due to decoding, shifting, or packaging, for example.

Definition at line 87 of file multi.hh.

◆ multiStats

gem5::compression::Multi::MultiStats gem5::compression::Multi::multiStats

protected

Referenced by compress().

◆ numEncodingBits

const std::size_t gem5::compression::Multi::numEncodingBits

protected

An encoding is associated to each sub-compressor to inform which sub-compressor to use when decompressing data.

This information can be added either to the tag entry, in which case no extra bits are added to the compressed data (numEncodingBits = 0), or to the compressed data itself.

There is no encoding reserved for the uncompressed case; it is assumed that an "is compressed" bit is stored in the tags. Therefore, even if storing the encoding within the compressed data, these extra bits are not added when the data is uncompressible.

These extra bits are taken into account when thresholding the compressed data's size.

Definition at line 80 of file multi.hh.

Referenced by compress().

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

mem/cache/compressors/multi.hh
mem/cache/compressors/multi.cc

Classes

Public Types

Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ Params

Constructor & Destructor Documentation

◆ Multi()

◆ ~Multi()

Member Function Documentation

◆ compress()

◆ decompress()

◆ setCache()

Member Data Documentation

◆ compressors

◆ extraDecompressionLatency

◆ multiStats

◆ numEncodingBits