gem5
v20.1.0.0
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#include <tage_sc_l.hh>
Classes | |
struct | BranchInfo |
Public Member Functions | |
virtual TAGEBase::BranchInfo * | makeBranchInfo () override |
TAGE_SC_L_TAGE (const TAGE_SC_L_TAGEParams *p) | |
void | calculateParameters () override |
Calculates the history lengths and some other paramters in derived classes. More... | |
void | buildTageTables () override |
Instantiates the TAGE table entries. More... | |
void | calculateIndicesAndTags (ThreadID tid, Addr branch_pc, TAGEBase::BranchInfo *bi) override |
On a prediction, calculates the TAGE indices and tags for all the different history lengths. More... | |
unsigned | getUseAltIdx (TAGEBase::BranchInfo *bi, Addr branch_pc) override |
Calculation of the index for useAltPredForNewlyAllocated On this base TAGE implementation it is always 0. More... | |
void | updateHistories (ThreadID tid, Addr branch_pc, bool taken, TAGEBase::BranchInfo *b, bool speculative, const StaticInstPtr &inst, Addr target) override |
(Speculatively) updates global histories (path and direction). More... | |
int | bindex (Addr pc_in) const override |
Computes the index used to access the bimodal table. More... | |
int | gindex (ThreadID tid, Addr pc, int bank) const override |
Computes the index used to access a partially tagged table. More... | |
virtual int | gindex_ext (int index, int bank) const =0 |
int | F (int phist, int size, int bank) const override |
Utility function to shuffle the path history depending on which tagged table we are accessing. More... | |
virtual uint16_t | gtag (ThreadID tid, Addr pc, int bank) const override=0 |
Computes the partial tag of a tagged table. More... | |
void | squash (ThreadID tid, bool taken, TAGEBase::BranchInfo *bi, Addr target) override |
Restores speculatively updated path and direction histories. More... | |
void | updatePathAndGlobalHistory (ThreadHistory &tHist, int brtype, bool taken, Addr branch_pc, Addr target) |
void | adjustAlloc (bool &alloc, bool taken, bool pred_taken) override |
Extra calculation to tell whether TAGE allocaitons may happen or not on an update For this base TAGE implementation it does nothing. More... | |
virtual void | handleAllocAndUReset (bool alloc, bool taken, TAGEBase::BranchInfo *bi, int nrand) override=0 |
Handles Allocation and U bits reset on an update. More... | |
void | handleUReset () override |
Handles the U bits reset. More... | |
virtual void | handleTAGEUpdate (Addr branch_pc, bool taken, TAGEBase::BranchInfo *bi) override=0 |
Handles the update of the TAGE entries. More... | |
int | calcDep (TAGEBase::BranchInfo *bi) |
bool | getBimodePred (Addr branch_pc, TAGEBase::BranchInfo *tage_bi) const override |
Get a branch prediction from the bimodal predictor. More... | |
void | extraAltCalc (TAGEBase::BranchInfo *bi) override |
Extra steps for calculating altTaken For this base TAGE class it does nothing. More... | |
Public Member Functions inherited from TAGEBase | |
TAGEBase (const TAGEBaseParams *p) | |
void | init () override |
init() is called after all C++ SimObjects have been created and all ports are connected. More... | |
void | baseUpdate (Addr pc, bool taken, BranchInfo *bi) |
Updates the bimodal predictor. More... | |
void | updateGHist (uint8_t *&h, bool dir, uint8_t *tab, int &PT) |
(Speculatively) updates the global branch history. More... | |
void | update (ThreadID tid, Addr branch_pc, bool taken, BranchInfo *bi) |
Update TAGE. More... | |
virtual void | condBranchUpdate (ThreadID tid, Addr branch_pc, bool taken, BranchInfo *bi, int nrand, Addr corrTarget, bool pred, bool preAdjustAlloc=false) |
Update TAGE for conditional branches. More... | |
bool | tagePredict (ThreadID tid, Addr branch_pc, bool cond_branch, BranchInfo *bi) |
TAGE prediction called from TAGE::predict. More... | |
virtual void | updateStats (bool taken, BranchInfo *bi) |
Update the stats. More... | |
virtual void | resetUctr (uint8_t &u) |
Algorithm for resetting a single U counter. More... | |
virtual bool | isHighConfidence (BranchInfo *bi) const |
void | btbUpdate (ThreadID tid, Addr branch_addr, BranchInfo *&bi) |
unsigned | getGHR (ThreadID tid, BranchInfo *bi) const |
int8_t | getCtr (int hitBank, int hitBankIndex) const |
unsigned | getTageCtrBits () const |
int | getPathHist (ThreadID tid) const |
bool | isSpeculativeUpdateEnabled () const |
size_t | getSizeInBits () const |
Public Member Functions inherited from SimObject | |
const Params * | params () const |
SimObject (const Params *_params) | |
virtual | ~SimObject () |
virtual const std::string | name () const |
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... | |
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 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. 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 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 (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... | |
const Info * | resolveStat (std::string name) const |
Resolve a stat by its name within this group. More... | |
Group ()=delete | |
Group (const Group &)=delete | |
Group & | operator= (const Group &)=delete |
Private Attributes | |
const unsigned | firstLongTagTable |
const unsigned | longTagsSize |
const unsigned | shortTagsSize |
const unsigned | logTagTableSize |
const unsigned | shortTagsTageFactor |
const unsigned | longTagsTageFactor |
const bool | truncatePathHist |
Additional Inherited Members | |
Public Types inherited from TAGEBase | |
enum | { BIMODAL_ONLY = 0, TAGE_LONGEST_MATCH, BIMODAL_ALT_MATCH, TAGE_ALT_MATCH, LAST_TAGE_PROVIDER_TYPE = TAGE_ALT_MATCH } |
Public Types inherited from SimObject | |
typedef SimObjectParams | Params |
Static Public Member Functions inherited from TAGEBase | |
template<typename T > | |
static void | ctrUpdate (T &ctr, bool taken, int nbits) |
Updates a direction counter based on the actual branch outcome. More... | |
static void | unsignedCtrUpdate (uint8_t &ctr, bool up, unsigned nbits) |
Updates an unsigned counter based on up/down parameter. More... | |
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 () |
Gets the fully-qualified name of the active section. More... | |
static void | serializeAll (const std::string &cpt_dir) |
Serializes all the SimObjects. More... | |
static void | unserializeGlobals (CheckpointIn &cp) |
Protected Member Functions inherited from TAGEBase | |
virtual void | initFoldedHistories (ThreadHistory &history) |
Initialization of the folded histories. More... | |
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 Attributes inherited from TAGEBase | |
const unsigned | logRatioBiModalHystEntries |
const unsigned | nHistoryTables |
const unsigned | tagTableCounterBits |
const unsigned | tagTableUBits |
const unsigned | histBufferSize |
const unsigned | minHist |
const unsigned | maxHist |
const unsigned | pathHistBits |
std::vector< unsigned > | tagTableTagWidths |
std::vector< int > | logTagTableSizes |
std::vector< bool > | btablePrediction |
std::vector< bool > | btableHysteresis |
TageEntry ** | gtable |
std::vector< ThreadHistory > | threadHistory |
int * | histLengths |
int * | tableIndices |
int * | tableTags |
std::vector< int8_t > | useAltPredForNewlyAllocated |
int64_t | tCounter |
uint64_t | logUResetPeriod |
const int64_t | initialTCounterValue |
unsigned | numUseAltOnNa |
unsigned | useAltOnNaBits |
unsigned | maxNumAlloc |
std::vector< bool > | noSkip |
const bool | speculativeHistUpdate |
const unsigned | instShiftAmt |
bool | initialized |
TAGEBase::TAGEBaseStats | 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... | |
Definition at line 52 of file tage_sc_l.hh.
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inline |
Definition at line 79 of file tage_sc_l.hh.
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overridevirtual |
Extra calculation to tell whether TAGE allocaitons may happen or not on an update For this base TAGE implementation it does nothing.
Reimplemented from TAGEBase.
Definition at line 296 of file tage_sc_l.cc.
References Random::random(), and random_mt.
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overridevirtual |
Computes the index used to access the bimodal table.
pc_in | The unshifted branch PC. |
Reimplemented from TAGEBase.
Definition at line 223 of file tage_sc_l.cc.
References TAGEBase::instShiftAmt, TAGEBase::logTagTableSizes, MipsISA::pc, and ULL.
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overridevirtual |
Instantiates the TAGE table entries.
Reimplemented from TAGEBase.
Definition at line 111 of file tage_sc_l.cc.
References firstLongTagTable, TAGEBase::gtable, ArmISA::i, logTagTableSize, longTagsTageFactor, TAGEBase::nHistoryTables, and shortTagsTageFactor.
int TAGE_SC_L_TAGE::calcDep | ( | TAGEBase::BranchInfo * | bi | ) |
Definition at line 305 of file tage_sc_l.cc.
References ArmISA::a, PowerISA::bi, Random::random(), and random_mt.
Referenced by TAGE_SC_L_TAGE_8KB::handleAllocAndUReset(), and TAGE_SC_L_TAGE_64KB::handleAllocAndUReset().
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overridevirtual |
On a prediction, calculates the TAGE indices and tags for all the different history lengths.
Reimplemented from TAGEBase.
Definition at line 128 of file tage_sc_l.cc.
References PowerISA::bi, firstLongTagTable, gindex(), gtag(), TAGEBase::histLengths, ArmISA::i, TAGEBase::logTagTableSizes, longTagsTageFactor, TAGEBase::nHistoryTables, TAGEBase::noSkip, MipsISA::pc, shortTagsTageFactor, ArmISA::t, TAGEBase::tableIndices, TAGEBase::tableTags, and TAGEBase::threadHistory.
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overridevirtual |
Calculates the history lengths and some other paramters in derived classes.
Reimplemented from TAGEBase.
Definition at line 78 of file tage_sc_l.cc.
References firstLongTagTable, TAGEBase::histLengths, ArmISA::i, logTagTableSize, TAGEBase::logTagTableSizes, longTagsSize, TAGEBase::maxHist, TAGEBase::minHist, TAGEBase::nHistoryTables, shortTagsSize, and TAGEBase::tagTableTagWidths.
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overridevirtual |
Extra steps for calculating altTaken For this base TAGE class it does nothing.
Reimplemented from TAGEBase.
Definition at line 356 of file tage_sc_l.cc.
References TAGE_SC_L_TAGE::BranchInfo::altConf, PowerISA::bi, TAGEBase::TageEntry::ctr, and TAGEBase::gtable.
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overridevirtual |
Utility function to shuffle the path history depending on which tagged table we are accessing.
phist | The path history. |
size | Number of path history bits to use. |
bank | The partially tagged table to access. |
Reimplemented from TAGEBase.
Definition at line 199 of file tage_sc_l.cc.
References ArmISA::a, ArmISA::a1, TAGEBase::logTagTableSizes, and ULL.
Referenced by gindex(), and TAGE_SC_L_TAGE_8KB::gtag().
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overridevirtual |
Get a branch prediction from the bimodal predictor.
pc | The unshifted branch PC. |
bi | Pointer to information on the prediction. |
Reimplemented from TAGEBase.
Definition at line 340 of file tage_sc_l.cc.
References PowerISA::bi, TAGEBase::btableHysteresis, TAGEBase::btablePrediction, TAGEBase::getBimodePred(), TAGEBase::logRatioBiModalHystEntries, and MipsISA::pc.
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overridevirtual |
Calculation of the index for useAltPredForNewlyAllocated On this base TAGE implementation it is always 0.
Reimplemented from TAGEBase.
Definition at line 171 of file tage_sc_l.cc.
References PowerISA::bi, TAGEBase::numUseAltOnNa, and ArmISA::tbi.
Computes the index used to access a partially tagged table.
tid | The thread ID used to select the global histories to use. |
pc | The unshifted branch PC. |
bank | The partially tagged table to access. |
Reimplemented from TAGEBase.
Definition at line 180 of file tage_sc_l.cc.
References F(), gindex_ext(), TAGEBase::histLengths, MipsISA::index, TAGEBase::logTagTableSizes, TAGEBase::pathHistBits, MipsISA::pc, TAGEBase::threadHistory, and ULL.
Referenced by calculateIndicesAndTags().
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pure virtual |
Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.
Referenced by gindex().
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overridepure virtual |
Computes the partial tag of a tagged table.
tid | the thread ID used to select the global histories to use. |
pc | The unshifted branch PC. |
bank | The partially tagged table to access. |
Reimplemented from TAGEBase.
Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.
Referenced by calculateIndicesAndTags().
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overridepure virtual |
Handles Allocation and U bits reset on an update.
Reimplemented from TAGEBase.
Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.
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overridepure virtual |
Handles the update of the TAGE entries.
Reimplemented from TAGEBase.
Implemented in TAGE_SC_L_TAGE_64KB, and TAGE_SC_L_TAGE_8KB.
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overridevirtual |
Handles the U bits reset.
Reimplemented from TAGEBase.
Definition at line 316 of file tage_sc_l.cc.
References firstLongTagTable, TAGEBase::gtable, ArmISA::j, logTagTableSize, TAGEBase::logUResetPeriod, longTagsTageFactor, TAGEBase::resetUctr(), shortTagsTageFactor, TAGEBase::tCounter, ArmISA::u, and ULL.
Referenced by TAGE_SC_L_TAGE_8KB::handleAllocAndUReset(), and TAGE_SC_L_TAGE_64KB::handleAllocAndUReset().
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overridevirtual |
Reimplemented from TAGEBase.
Definition at line 73 of file tage_sc_l.cc.
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overridevirtual |
Restores speculatively updated path and direction histories.
Also recomputes compressed (folded) histories based on the correct branch outcome. This version of squash() is called once on a branch misprediction.
tid | The Thread ID to select the histories to rollback. |
taken | The correct branch outcome. |
bp_history | Wrapping pointer to BranchInfo (to allow storing derived class prediction information in the base class). |
target | The correct branch target |
Reimplemented from TAGEBase.
Definition at line 289 of file tage_sc_l.cc.
References fatal.
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overridevirtual |
(Speculatively) updates global histories (path and direction).
Also recomputes compressed (folded) histories based on the branch direction.
tid | The thread ID to select the histories to update. |
branch_pc | The unshifted branch PC. |
taken | (Predicted) branch direction. |
b | Wrapping pointer to BranchInfo (to allow storing derived class prediction information in the base class). |
Reimplemented from TAGEBase.
Definition at line 265 of file tage_sc_l.cc.
References DPRINTF, StaticInst::isDirectCtrl(), StaticInst::isUncondCtrl(), TAGEBase::ThreadHistory::pathHist, TAGEBase::ThreadHistory::ptGhist, TAGEBase::speculativeHistUpdate, TAGEBase::threadHistory, and updatePathAndGlobalHistory().
void TAGE_SC_L_TAGE::updatePathAndGlobalHistory | ( | ThreadHistory & | tHist, |
int | brtype, | ||
bool | taken, | ||
Addr | branch_pc, | ||
Addr | target | ||
) |
Definition at line 230 of file tage_sc_l.cc.
References TAGEBase::ThreadHistory::computeIndices, TAGEBase::ThreadHistory::computeTags, TAGEBase::ThreadHistory::gHist, TAGEBase::ThreadHistory::globalHistory, ArmISA::i, TAGEBase::instShiftAmt, TAGEBase::nHistoryTables, Serializable::path, TAGEBase::ThreadHistory::pathHist, TAGEBase::pathHistBits, TAGEBase::ThreadHistory::ptGhist, ArmISA::t, truncatePathHist, ULL, TAGEBase::FoldedHistory::update(), and TAGEBase::updateGHist().
Referenced by updateHistories().
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private |
Definition at line 53 of file tage_sc_l.hh.
Referenced by buildTageTables(), calculateIndicesAndTags(), calculateParameters(), and handleUReset().
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private |
Definition at line 57 of file tage_sc_l.hh.
Referenced by buildTageTables(), calculateParameters(), and handleUReset().
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private |
Definition at line 54 of file tage_sc_l.hh.
Referenced by calculateParameters().
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private |
Definition at line 60 of file tage_sc_l.hh.
Referenced by buildTageTables(), calculateIndicesAndTags(), and handleUReset().
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private |
Definition at line 55 of file tage_sc_l.hh.
Referenced by calculateParameters().
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private |
Definition at line 59 of file tage_sc_l.hh.
Referenced by buildTageTables(), calculateIndicesAndTags(), and handleUReset().
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private |
Definition at line 62 of file tage_sc_l.hh.
Referenced by updatePathAndGlobalHistory().