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gem5
v21.1.0.2
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#include <loop_predictor.hh>
Classes | |
| struct | BranchInfo |
| struct | LoopEntry |
| struct | LoopPredictorStats |
Public Member Functions | |
| int | lindex (Addr pc_in, unsigned instShiftAmt) const |
| Computes the index used to access the loop predictor. More... | |
| int | finallindex (int lindex, int lowPcBits, int way) const |
| Computes the index used to access the ltable structures. More... | |
| bool | getLoop (Addr pc, BranchInfo *bi, bool speculative, unsigned instShiftAmt) const |
| Get a branch prediction from the loop predictor. More... | |
| void | loopUpdate (Addr pc, bool Taken, BranchInfo *bi, bool tage_pred) |
| Updates the loop predictor. More... | |
| void | specLoopUpdate (bool taken, BranchInfo *bi) |
| Speculatively updates the loop predictor iteration count (only for useSpeculation). More... | |
| void | condBranchUpdate (ThreadID tid, Addr branch_pc, bool taken, bool tage_pred, BranchInfo *bi, unsigned instShiftAmt) |
| Update LTAGE for conditional branches. More... | |
| bool | loopPredict (ThreadID tid, Addr branch_pc, bool cond_branch, BranchInfo *bi, bool prev_pred_taken, unsigned instShiftAmt) |
| Get the loop prediction. More... | |
| void | updateStats (bool taken, BranchInfo *bi) |
| Update the stats. More... | |
| void | squashLoop (BranchInfo *bi) |
| void | squash (ThreadID tid, BranchInfo *bi) |
| virtual bool | calcConf (int index) const |
| virtual bool | optionalAgeInc () const |
| virtual BranchInfo * | makeBranchInfo () |
| int8_t | getLoopUseCounter () const |
| Gets the value of the loop use counter. More... | |
| void | init () override |
| Initialize the loop predictor. More... | |
| LoopPredictor (const LoopPredictorParams &p) | |
| size_t | getSizeInBits () const |
Public Member Functions inherited from gem5::SimObject | |
| const Params & | params () const |
| SimObject (const Params &p) | |
| virtual | ~SimObject () |
| 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 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. 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 Info * | resolveStat (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 | |
| 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 |
Static Protected Member Functions | |
| static void | unsignedCtrUpdate (uint8_t &ctr, bool up, unsigned nbits) |
| Updates an unsigned counter based on up/down parameter. More... | |
| static void | signedCtrUpdate (int8_t &ctr, bool up, unsigned nbits) |
Protected Attributes | |
| const unsigned | logSizeLoopPred |
| const unsigned | loopTableAgeBits |
| const unsigned | loopTableConfidenceBits |
| const unsigned | loopTableTagBits |
| const unsigned | loopTableIterBits |
| const unsigned | logLoopTableAssoc |
| const uint8_t | confidenceThreshold |
| const uint16_t | loopTagMask |
| const uint16_t | loopNumIterMask |
| const int | loopSetMask |
| LoopEntry * | ltable |
| int8_t | loopUseCounter |
| unsigned | withLoopBits |
| const bool | useDirectionBit |
| const bool | useSpeculation |
| const bool | useHashing |
| const bool | restrictAllocation |
| const unsigned | initialLoopIter |
| const unsigned | initialLoopAge |
| const bool | optionalAgeReset |
| gem5::branch_prediction::LoopPredictor::LoopPredictorStats | stats |
Protected Attributes inherited from gem5::SimObject | |
| const SimObjectParams & | _params |
| Cached copy of the object parameters. More... | |
Protected Attributes inherited from gem5::EventManager | |
| EventQueue * | eventq |
| A pointer to this object's event queue. More... | |
Additional Inherited Members | |
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. More... | |
| static SimObject * | find (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 SimObjectResolver * | getSimObjectResolver () |
| 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... | |
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... | |
Definition at line 49 of file loop_predictor.hh.
| gem5::branch_prediction::LoopPredictor::LoopPredictor | ( | const LoopPredictorParams & | p | ) |
Definition at line 47 of file loop_predictor.cc.
References initialLoopAge, and loopTableAgeBits.
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Reimplemented in gem5::branch_prediction::TAGE_SC_L_LoopPredictor, and gem5::branch_prediction::MPP_LoopPredictor.
Definition at line 156 of file loop_predictor.cc.
References gem5::branch_prediction::LoopPredictor::LoopEntry::confidence, confidenceThreshold, gem5::MipsISA::index, and ltable.
Referenced by gem5::branch_prediction::MPP_LoopPredictor::calcConf(), gem5::branch_prediction::TAGE_SC_L_LoopPredictor::calcConf(), and getLoop().
| void gem5::branch_prediction::LoopPredictor::condBranchUpdate | ( | ThreadID | tid, |
| Addr | branch_pc, | ||
| bool | taken, | ||
| bool | tage_pred, | ||
| BranchInfo * | bi, | ||
| unsigned | instShiftAmt | ||
| ) |
Update LTAGE for conditional branches.
| branch_pc | The unshifted branch PC. |
| taken | Actual branch outcome. |
| tage_pred | Prediction from TAGE |
| bi | Pointer to information on the prediction recorded at prediction time. |
| instShiftAmt | Number of bits to shift instructions |
Definition at line 331 of file loop_predictor.cc.
References gem5::PowerISA::bi, getLoop(), loopUpdate(), loopUseCounter, signedCtrUpdate(), useSpeculation, and withLoopBits.
Referenced by gem5::branch_prediction::LTAGE::update(), gem5::branch_prediction::TAGE_SC_L::update(), and gem5::branch_prediction::MultiperspectivePerceptronTAGE::update().
| int gem5::branch_prediction::LoopPredictor::finallindex | ( | int | lindex, |
| int | lowPcBits, | ||
| int | way | ||
| ) | const |
Computes the index used to access the ltable structures.
It may take hashing into account
| index | Result of lindex function |
| lowPcBits | PC bits masked with set size |
| way | Way to be used |
Definition at line 109 of file loop_predictor.cc.
References gem5::MipsISA::index, logLoopTableAssoc, and useHashing.
Referenced by getLoop(), loopUpdate(), specLoopUpdate(), squash(), and squashLoop().
| bool gem5::branch_prediction::LoopPredictor::getLoop | ( | Addr | pc, |
| BranchInfo * | bi, | ||
| bool | speculative, | ||
| unsigned | instShiftAmt | ||
| ) | const |
Get a branch prediction from the loop predictor.
| pc | The unshifted branch PC. |
| bi | Pointer to information on the prediction. |
| speculative | Use speculative number of iterations |
| instShiftAmt | Shift the pc by as many bits (if hashing is not used) |
Definition at line 118 of file loop_predictor.cc.
References gem5::PowerISA::bi, calcConf(), gem5::branch_prediction::LoopPredictor::LoopEntry::currentIter, gem5::branch_prediction::LoopPredictor::LoopEntry::currentIterSpec, gem5::branch_prediction::LoopPredictor::LoopEntry::dir, finallindex(), gem5::ArmISA::i, lindex(), logLoopTableAssoc, logSizeLoopPred, loopSetMask, loopTableTagBits, loopTagMask, ltable, gem5::MipsISA::pc, useDirectionBit, and useHashing.
Referenced by condBranchUpdate(), and loopPredict().
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Gets the value of the loop use counter.
Definition at line 252 of file loop_predictor.hh.
References loopUseCounter.
Referenced by gem5::branch_prediction::LTAGE::predict().
| size_t gem5::branch_prediction::LoopPredictor::getSizeInBits | ( | ) | const |
Definition at line 367 of file loop_predictor.cc.
References logSizeLoopPred, loopTableAgeBits, loopTableConfidenceBits, loopTableIterBits, loopTableTagBits, useDirectionBit, and useSpeculation.
Referenced by gem5::branch_prediction::MultiperspectivePerceptronTAGE::init().
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overridevirtual |
Initialize the loop predictor.
Reimplemented from gem5::SimObject.
Definition at line 73 of file loop_predictor.cc.
References logLoopTableAssoc, logSizeLoopPred, loopTableIterBits, loopTableTagBits, and ltable.
| int gem5::branch_prediction::LoopPredictor::lindex | ( | Addr | pc_in, |
| unsigned | instShiftAmt | ||
| ) | const |
Computes the index used to access the loop predictor.
| pc_in | The unshifted branch PC. |
| instShiftAmt | Shift the pc by as many bits |
Definition at line 92 of file loop_predictor.cc.
References logLoopTableAssoc, loopSetMask, gem5::MipsISA::pc, and useHashing.
Referenced by getLoop().
| bool gem5::branch_prediction::LoopPredictor::loopPredict | ( | ThreadID | tid, |
| Addr | branch_pc, | ||
| bool | cond_branch, | ||
| BranchInfo * | bi, | ||
| bool | prev_pred_taken, | ||
| unsigned | instShiftAmt | ||
| ) |
Get the loop prediction.
| tid | The thread ID to select the global histories to use. |
| branch_pc | The unshifted branch PC. |
| cond_branch | True if the branch is conditional. |
| bi | Reference to wrapping pointer to allow storing derived class prediction information in the base class. |
| prev_pred_taken | Result of the TAGE prediction |
| instShiftAmt | Shift the pc by as many bits |
| instShiftAmt | Shift the pc by as many bits |
Definition at line 277 of file loop_predictor.cc.
References gem5::PowerISA::bi, getLoop(), loopUseCounter, specLoopUpdate(), and useSpeculation.
Referenced by gem5::branch_prediction::MultiperspectivePerceptronTAGE::lookup(), gem5::branch_prediction::LTAGE::predict(), and gem5::branch_prediction::TAGE_SC_L::predict().
| void gem5::branch_prediction::LoopPredictor::loopUpdate | ( | Addr | pc, |
| bool | Taken, | ||
| BranchInfo * | bi, | ||
| bool | tage_pred | ||
| ) |
Updates the loop predictor.
| pc | The unshifted branch PC. |
| taken | The actual branch outcome. |
| bi | Pointer to information on the prediction recorded at prediction time. |
| tage_pred | tage prediction of the branch |
Definition at line 182 of file loop_predictor.cc.
References gem5::branch_prediction::LoopPredictor::LoopEntry::age, gem5::PowerISA::bi, gem5::branch_prediction::LoopPredictor::LoopEntry::confidence, gem5::branch_prediction::LoopPredictor::LoopEntry::currentIter, gem5::branch_prediction::LoopPredictor::LoopEntry::dir, DPRINTF, finallindex(), gem5::ArmISA::i, initialLoopAge, initialLoopIter, logLoopTableAssoc, loopNumIterMask, loopTableAgeBits, loopTableConfidenceBits, ltable, gem5::branch_prediction::LoopPredictor::LoopEntry::numIter, optionalAgeInc(), optionalAgeReset, gem5::MipsISA::pc, gem5::Random::random(), gem5::random_mt, restrictAllocation, gem5::branch_prediction::LoopPredictor::LoopEntry::tag, unsignedCtrUpdate(), and useDirectionBit.
Referenced by condBranchUpdate().
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Definition at line 86 of file loop_predictor.cc.
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Reimplemented in gem5::branch_prediction::TAGE_SC_L_LoopPredictor, and gem5::branch_prediction::MPP_LoopPredictor.
Definition at line 176 of file loop_predictor.cc.
Referenced by loopUpdate().
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inlinestaticprotected |
Definition at line 117 of file loop_predictor.hh.
References gem5::ArmISA::up.
Referenced by condBranchUpdate().
| void gem5::branch_prediction::LoopPredictor::specLoopUpdate | ( | bool | taken, |
| BranchInfo * | bi | ||
| ) |
Speculatively updates the loop predictor iteration count (only for useSpeculation).
| taken | The predicted branch outcome. |
| bi | Pointer to information on the prediction recorded at prediction time. |
Definition at line 162 of file loop_predictor.cc.
References gem5::PowerISA::bi, gem5::branch_prediction::LoopPredictor::LoopEntry::currentIterSpec, finallindex(), gem5::MipsISA::index, loopNumIterMask, and ltable.
Referenced by loopPredict().
| void gem5::branch_prediction::LoopPredictor::squash | ( | ThreadID | tid, |
| BranchInfo * | bi | ||
| ) |
Definition at line 299 of file loop_predictor.cc.
References gem5::PowerISA::bi, gem5::branch_prediction::LoopPredictor::LoopEntry::currentIterSpec, finallindex(), and ltable.
Referenced by gem5::branch_prediction::LTAGE::squash().
| void gem5::branch_prediction::LoopPredictor::squashLoop | ( | BranchInfo * | bi | ) |
Definition at line 310 of file loop_predictor.cc.
References gem5::PowerISA::bi, gem5::branch_prediction::LoopPredictor::LoopEntry::currentIterSpec, finallindex(), and ltable.
Referenced by gem5::branch_prediction::LTAGE::update(), gem5::branch_prediction::TAGE_SC_L::update(), and gem5::branch_prediction::MultiperspectivePerceptronTAGE::update().
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inlinestaticprotected |
Updates an unsigned counter based on up/down parameter.
| ctr | Reference to counter to update. |
| up | Boolean indicating if the counter is incremented/decremented If true it is incremented, if false it is decremented |
| nbits | Counter width. |
Definition at line 106 of file loop_predictor.hh.
References gem5::ArmISA::up.
Referenced by loopUpdate().
| void gem5::branch_prediction::LoopPredictor::updateStats | ( | bool | taken, |
| BranchInfo * | bi | ||
| ) |
Update the stats.
| taken | Actual branch outcome |
| bi | Pointer to information on the prediction recorded at prediction time. |
Definition at line 321 of file loop_predictor.cc.
References gem5::PowerISA::bi, gem5::branch_prediction::LoopPredictor::LoopPredictorStats::correct, stats, and gem5::branch_prediction::LoopPredictor::LoopPredictorStats::wrong.
Referenced by gem5::branch_prediction::LTAGE::update(), gem5::branch_prediction::TAGE_SC_L::update(), and gem5::branch_prediction::MultiperspectivePerceptronTAGE::update().
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Definition at line 58 of file loop_predictor.hh.
Referenced by calcConf().
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Definition at line 89 of file loop_predictor.hh.
Referenced by LoopPredictor(), and loopUpdate().
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Definition at line 88 of file loop_predictor.hh.
Referenced by loopUpdate().
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Definition at line 57 of file loop_predictor.hh.
Referenced by finallindex(), getLoop(), init(), lindex(), and loopUpdate().
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Definition at line 52 of file loop_predictor.hh.
Referenced by getLoop(), getSizeInBits(), and init().
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Definition at line 60 of file loop_predictor.hh.
Referenced by loopUpdate(), and specLoopUpdate().
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Definition at line 61 of file loop_predictor.hh.
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Definition at line 53 of file loop_predictor.hh.
Referenced by getSizeInBits(), LoopPredictor(), and loopUpdate().
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Definition at line 54 of file loop_predictor.hh.
Referenced by getSizeInBits(), and loopUpdate().
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Definition at line 56 of file loop_predictor.hh.
Referenced by getSizeInBits(), and init().
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Definition at line 55 of file loop_predictor.hh.
Referenced by getLoop(), getSizeInBits(), and init().
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Definition at line 59 of file loop_predictor.hh.
Referenced by getLoop().
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Definition at line 81 of file loop_predictor.hh.
Referenced by condBranchUpdate(), getLoopUseCounter(), and loopPredict().
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Definition at line 79 of file loop_predictor.hh.
Referenced by gem5::branch_prediction::MPP_LoopPredictor::calcConf(), gem5::branch_prediction::TAGE_SC_L_LoopPredictor::calcConf(), calcConf(), getLoop(), init(), loopUpdate(), specLoopUpdate(), squash(), and squashLoop().
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Definition at line 90 of file loop_predictor.hh.
Referenced by loopUpdate().
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Definition at line 87 of file loop_predictor.hh.
Referenced by loopUpdate().
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Referenced by updateStats().
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Definition at line 84 of file loop_predictor.hh.
Referenced by getLoop(), getSizeInBits(), and loopUpdate().
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Definition at line 86 of file loop_predictor.hh.
Referenced by finallindex(), getLoop(), and lindex().
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Definition at line 85 of file loop_predictor.hh.
Referenced by condBranchUpdate(), getSizeInBits(), and loopPredict().
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Definition at line 82 of file loop_predictor.hh.
Referenced by condBranchUpdate().