gem5  v22.0.0.2
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gem5::compression::DictionaryCompressor< T > Class Template Referenceabstract

A template version of the dictionary compressor that allows to choose the dictionary size. More...

#include <dictionary_compressor.hh>

Inheritance diagram for gem5::compression::DictionaryCompressor< T >:
gem5::compression::BaseDictionaryCompressor gem5::compression::Base gem5::SimObject gem5::EventManager gem5::Serializable gem5::Drainable gem5::statistics::Group gem5::Named

Classes

class  CompData
 
class  DeltaPattern
 A pattern that checks whether the difference of the value and the dictionary entries' is below a certain threshold. More...
 
struct  Factory
 Create a factory to determine if input matches a pattern. More...
 
struct  Factory< Head >
 Specialization to end the recursion. More...
 
class  LocatedMaskedPattern
 A pattern that narrows the MaskedPattern by allowing a only single possible dictionary entry to be matched against. More...
 
class  MaskedPattern
 A pattern that compares masked values against dictionary entries. More...
 
class  MaskedValuePattern
 A pattern that compares masked values to a masked portion of a fixed value. More...
 
class  Pattern
 The compressed data is composed of multiple pattern entries. More...
 
class  RepeatedValuePattern
 A pattern that checks if dictionary entry sized values are solely composed of multiple copies of a single value. More...
 
class  SignExtendedPattern
 A pattern that checks whether the value is an N bits sign-extended value, that is, all the MSB starting from the Nth are equal to the (N-1)th bit. More...
 
class  UncompressedPattern
 A pattern containing the original uncompressed data. More...
 

Public Types

typedef BaseDictionaryCompressorParams Params
 
- Public Types inherited from gem5::compression::BaseDictionaryCompressor
typedef BaseDictionaryCompressorParams Params
 
- Public Types inherited from gem5::compression::Base
typedef BaseCacheCompressorParams Params
 
- Public Types inherited from gem5::SimObject
typedef SimObjectParams Params
 

Public Member Functions

 DictionaryCompressor (const Params &p)
 
 ~DictionaryCompressor ()=default
 
- Public Member Functions inherited from gem5::compression::BaseDictionaryCompressor
 BaseDictionaryCompressor (const Params &p)
 
 ~BaseDictionaryCompressor ()=default
 
- Public Member Functions inherited from gem5::compression::Base
 Base (const Params &p)
 
virtual ~Base ()=default
 
virtual void setCache (BaseCache *_cache)
 The cache can only be set once. More...
 
std::unique_ptr< CompressionDatacompress (const uint64_t *data, Cycles &comp_lat, Cycles &decomp_lat)
 Apply the compression process to the cache line. More...
 
Cycles getDecompressionLatency (const CacheBlk *blk)
 Get the decompression latency if the block is compressed. More...
 
- Public Member Functions inherited from gem5::SimObject
const Paramsparams () 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. 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...
 
ProbeManagergetProbeManager ()
 Get the probe manager for this object. More...
 
virtual PortgetPort (const std::string &if_name, PortID idx=InvalidPortID)
 Get a port with a given name and index. More...
 
virtual void startup ()
 startup() is the final initialization call before simulation. 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 gem5::EventManager
EventQueueeventQueue () 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. More...
 
void setCurTick (Tick newVal)
 
 EventManager (EventManager &em)
 Event manger manages events in the event queue. More...
 
 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. 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 gem5::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 gem5::statistics::Group
 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 (statistics::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...
 
const InforesolveStat (std::string name) const
 Resolve a stat by its name within this group. More...
 
void mergeStatGroup (Group *block)
 Merge the contents (stats & children) of a block to this block. More...
 
 Group ()=delete
 
 Group (const Group &)=delete
 
Groupoperator= (const Group &)=delete
 
- Public Member Functions inherited from gem5::Named
 Named (const std::string &name_)
 
virtual ~Named ()=default
 
virtual std::string name () const
 

Protected Types

typedef std::array< uint8_t, sizeof(T)> DictionaryEntry
 Convenience typedef for a dictionary entry. More...
 
- Protected Types inherited from gem5::compression::Base
typedef uint64_t Chunk
 A chunk is a basic lexical unit. More...
 

Protected Member Functions

virtual std::unique_ptr< PatterngetPattern (const DictionaryEntry &bytes, const DictionaryEntry &dict_bytes, const int match_location) const =0
 Since the factory cannot be instantiated here, classes that inherit from this base class have to implement the call to their factory's getPattern. More...
 
std::unique_ptr< PatterncompressValue (const T data)
 Compress data. More...
 
decompressValue (const Pattern *pattern)
 Decompress a pattern into a value that fits in a dictionary entry. More...
 
virtual void resetDictionary ()
 Clear all dictionary entries. More...
 
virtual void addToDictionary (const DictionaryEntry data)=0
 Add an entry to the dictionary. More...
 
virtual std::unique_ptr< DictionaryCompressor::CompDatainstantiateDictionaryCompData () const
 Instantiate a compression data of the sub-class compressor. More...
 
std::unique_ptr< Base::CompressionDatacompress (const std::vector< Chunk > &chunks)
 Apply compression. More...
 
std::unique_ptr< Base::CompressionDatacompress (const std::vector< Chunk > &chunks, Cycles &comp_lat, Cycles &decomp_lat) override
 Apply the compression process to the cache line. More...
 
void decompress (const CompressionData *comp_data, uint64_t *data) override
 Apply the decompression process to the compressed data. More...
 
- Protected Member Functions inherited from gem5::compression::BaseDictionaryCompressor
virtual uint64_t getNumPatterns () const =0
 Trick function to get the number of patterns. More...
 
virtual std::string getName (int number) const =0
 Get meta-name assigned to the given pattern. More...
 
- Protected Member Functions inherited from gem5::compression::Base
std::vector< ChunktoChunks (const uint64_t *data) const
 This function splits the raw data into chunks, so that it can be parsed by the compressor. More...
 
void fromChunks (const std::vector< Chunk > &chunks, uint64_t *data) const
 This function re-joins the chunks to recreate the original data. More...
 
- Protected Member Functions inherited from gem5::Drainable
 Drainable ()
 
virtual ~Drainable ()
 
virtual void drainResume ()
 Resume execution after a successful drain. More...
 
void signalDrainDone () const
 Signal that an object is drained. More...
 

Static Protected Member Functions

static DictionaryEntry toDictionaryEntry (T value)
 Turn a value into a dictionary entry. More...
 
static T fromDictionaryEntry (const DictionaryEntry &entry)
 Turn a dictionary entry into a value. More...
 

Protected Attributes

std::vector< DictionaryEntrydictionary
 The dictionary. More...
 
- Protected Attributes inherited from gem5::compression::BaseDictionaryCompressor
const std::size_t dictionarySize
 Dictionary size. More...
 
std::size_t numEntries
 Number of valid entries in the dictionary. More...
 
gem5::compression::BaseDictionaryCompressor::DictionaryStats dictionaryStats
 
- Protected Attributes inherited from gem5::compression::Base
const std::size_t blkSize
 Uncompressed cache line size (in bytes). More...
 
const unsigned chunkSizeBits
 Chunk size, in number of bits. More...
 
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. More...
 
const Cycles compChunksPerCycle
 Degree of parallelization of the compression process. More...
 
const Cycles compExtraLatency
 Extra latency added to compression due to packaging, shifting or other operations. More...
 
const Cycles decompChunksPerCycle
 Degree of parallelization of the decompression process. More...
 
const Cycles decompExtraLatency
 Extra latency added to decompression due to packaging, shifting or other operations. More...
 
BaseCachecache
 Pointer to the parent cache. More...
 
gem5::compression::Base::BaseStats stats
 
- Protected Attributes inherited from gem5::SimObject
const SimObjectParams & _params
 Cached copy of the object parameters. More...
 
- Protected Attributes inherited from gem5::EventManager
EventQueueeventq
 A pointer to this object's event queue. More...
 

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. More...
 
static void setSizeBits (CacheBlk *blk, const std::size_t size_bits)
 Set the size of the compressed block, in bits. More...
 
- 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. More...
 
static SimObjectfind (const char *name)
 Find the SimObject with the given name and return a pointer to it. More...
 
static void setSimObjectResolver (SimObjectResolver *resolver)
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
static SimObjectResolvergetSimObjectResolver ()
 There is a single object name resolver, and it is only set when simulation is restoring from checkpoints. More...
 
- Static Public Member Functions inherited from gem5::Serializable
static const std::string & currentSection ()
 Gets the fully-qualified name of the active section. More...
 
static void generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
 Generate a checkpoint file so that the serialization can be routed to it. More...
 

Detailed Description

template<class T>
class gem5::compression::DictionaryCompressor< T >

A template version of the dictionary compressor that allows to choose the dictionary size.

Template Parameters
Thetype of a dictionary entry (e.g., uint16_t, uint32_t, etc).

Definition at line 118 of file dictionary_compressor.hh.

Member Typedef Documentation

◆ DictionaryEntry

template<class T >
typedef std::array<uint8_t, sizeof(T)> gem5::compression::DictionaryCompressor< T >::DictionaryEntry
protected

Convenience typedef for a dictionary entry.

Definition at line 122 of file dictionary_compressor.hh.

◆ Params

template<class T >
typedef BaseDictionaryCompressorParams gem5::compression::DictionaryCompressor< T >::Params

Definition at line 274 of file dictionary_compressor.hh.

Constructor & Destructor Documentation

◆ DictionaryCompressor()

template<class T >
gem5::compression::DictionaryCompressor< T >::DictionaryCompressor ( const Params p)

Definition at line 68 of file dictionary_compressor_impl.hh.

◆ ~DictionaryCompressor()

template<class T >
gem5::compression::DictionaryCompressor< T >::~DictionaryCompressor ( )
default

Member Function Documentation

◆ addToDictionary()

template<class T >
virtual void gem5::compression::DictionaryCompressor< T >::addToDictionary ( const DictionaryEntry  data)
protectedpure virtual

Add an entry to the dictionary.

Parameters
dataThe new entry.

◆ compress() [1/2]

template<class T >
std::unique_ptr< Base::CompressionData > gem5::compression::DictionaryCompressor< T >::compress ( const std::vector< Chunk > &  chunks)
protected

Apply compression.

Parameters
chunksThe cache line to be compressed.
Returns
Cache line after compression.

Definition at line 131 of file dictionary_compressor_impl.hh.

Referenced by gem5::compression::RepeatedQwords::compress(), and gem5::compression::Zero::compress().

◆ compress() [2/2]

template<class T >
std::unique_ptr< Base::CompressionData > gem5::compression::DictionaryCompressor< T >::compress ( const std::vector< Chunk > &  chunks,
Cycles comp_lat,
Cycles decomp_lat 
)
overrideprotectedvirtual

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
chunksThe cache line to be compressed, divided into chunks.
comp_latCompression latency in number of cycles.
decomp_latDecompression latency in number of cycles.
Returns
Cache line after compression.

Implements gem5::compression::Base.

Definition at line 154 of file dictionary_compressor_impl.hh.

◆ compressValue()

template<typename T >
std::unique_ptr< typename DictionaryCompressor< T >::Pattern > gem5::compression::DictionaryCompressor< T >::compressValue ( const T  data)
protected

Compress data.

Parameters
dataData to be compressed.
Returns
The pattern this data matches.

Definition at line 96 of file dictionary_compressor_impl.hh.

◆ decompress()

template<class T >
void gem5::compression::DictionaryCompressor< T >::decompress ( const CompressionData comp_data,
uint64_t *  cache_line 
)
overrideprotectedvirtual

Apply the decompression process to the compressed data.

Parameters
comp_dataCompressed cache line.
cache_lineThe cache line to be decompressed.

Implements gem5::compression::Base.

Definition at line 188 of file dictionary_compressor_impl.hh.

◆ decompressValue()

template<class T >
T gem5::compression::DictionaryCompressor< T >::decompressValue ( const Pattern pattern)
protected

Decompress a pattern into a value that fits in a dictionary entry.

Parameters
patternThe pattern to be decompressed.
Returns
The decompressed word.

Definition at line 169 of file dictionary_compressor_impl.hh.

◆ fromDictionaryEntry()

template<class T >
T gem5::compression::DictionaryCompressor< T >::fromDictionaryEntry ( const DictionaryEntry entry)
staticprotected

◆ getPattern()

template<class T >
virtual std::unique_ptr<Pattern> gem5::compression::DictionaryCompressor< T >::getPattern ( const DictionaryEntry bytes,
const DictionaryEntry dict_bytes,
const int  match_location 
) const
protectedpure virtual

Since the factory cannot be instantiated here, classes that inherit from this base class have to implement the call to their factory's getPattern.

◆ instantiateDictionaryCompData()

template<typename T >
std::unique_ptr< typename DictionaryCompressor< T >::CompData > gem5::compression::DictionaryCompressor< T >::instantiateDictionaryCompData
protectedvirtual

Instantiate a compression data of the sub-class compressor.

Returns
The new compression data entry.

Definition at line 89 of file dictionary_compressor_impl.hh.

◆ resetDictionary()

template<class T >
void gem5::compression::DictionaryCompressor< T >::resetDictionary
protectedvirtual

◆ toDictionaryEntry()

template<class T >
DictionaryCompressor< T >::DictionaryEntry gem5::compression::DictionaryCompressor< T >::toDictionaryEntry ( value)
staticprotected

Member Data Documentation

◆ dictionary

template<class T >
std::vector<DictionaryEntry> gem5::compression::DictionaryCompressor< T >::dictionary
protected

The dictionary.

Definition at line 195 of file dictionary_compressor.hh.


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

Generated on Thu Jul 28 2022 13:33:27 for gem5 by doxygen 1.8.17