Rename handles both single threaded and SMT rename. More...

#include <rename.hh>

Classes
struct	FreeEntries
	Structures whose free entries impact the amount of instructions that can be renamed. More...

struct	RenameHistory
	Holds the information for each destination register rename. More...

struct	RenameStats

struct	Stalls
	Source of possible stalls. More...

Public Types
enum	RenameStatus { Active , Inactive }
	Overall rename status. More...

enum	ThreadStatus { Running , Idle , StartSquash , Squashing , Blocked , Unblocking , SerializeStall }
	Individual thread status. More...

typedef std::deque< DynInstPtr >	InstQueue

Public Member Functions
	Rename (CPU *_cpu, const BaseO3CPUParams &params)
	Rename constructor.

std::string	name () const
	Returns the name of rename.

void	regProbePoints ()
	Registers probes.

void	setTimeBuffer (TimeBuffer< TimeStruct > *tb_ptr)
	Sets the main backwards communication time buffer pointer.

void	setRenameQueue (TimeBuffer< RenameStruct > *rq_ptr)
	Sets pointer to time buffer used to communicate to the next stage.

void	setDecodeQueue (TimeBuffer< DecodeStruct > *dq_ptr)
	Sets pointer to time buffer coming from decode.

void	setIEWStage (IEW *iew_stage)
	Sets pointer to IEW stage.

void	setCommitStage (Commit *commit_stage)
	Sets pointer to commit stage.

void	startupStage ()
	Initializes variables for the stage.

void	clearStates (ThreadID tid)
	Clear all thread-specific states.

void	setActiveThreads (std::list< ThreadID > *at_ptr)
	Sets pointer to list of active threads.

void	setRenameMap (UnifiedRenameMap::PerThreadUnifiedRenameMap &rm_ptr)
	Sets pointer to rename maps (per-thread structures).

void	setFreeList (UnifiedFreeList *fl_ptr)
	Sets pointer to the free list.

void	setScoreboard (Scoreboard *_scoreboard)
	Sets pointer to the scoreboard.

void	drainSanityCheck () const
	Perform sanity checks after a drain.

bool	isDrained () const
	Has the stage drained?

void	takeOverFrom ()
	Takes over from another CPU's thread.

void	squash (const InstSeqNum &squash_seq_num, ThreadID tid)
	Squashes all instructions in a thread.

void	tick ()
	Ticks rename, which processes all input signals and attempts to rename as many instructions as possible.

void	dumpHistory ()
	Debugging function used to dump history buffer of renamings.

Private Types
enum	FullSource { ROB , IQ , LQ , SQ , NONE }
	Enum to record the source of a structure full stall. More...

typedef std::pair< InstSeqNum, PhysRegIdPtr >	SeqNumRegPair
	Probe points.

Private Member Functions
void	resetStage ()
	Reset this pipeline stage.

void	rename (bool &status_change, ThreadID tid)
	Determines what to do based on rename's current status.

void	renameInsts (ThreadID tid)
	Renames instructions for the given thread.

void	skidInsert (ThreadID tid)
	Inserts unused instructions from a given thread into the skid buffer, to be renamed once rename unblocks.

void	sortInsts ()
	Separates instructions from decode into individual lists of instructions sorted by thread.

bool	skidsEmpty ()
	Returns if all of the skid buffers are empty.

void	updateStatus ()
	Updates overall rename status based on all of the threads' statuses.

bool	block (ThreadID tid)
	Switches rename to blocking, and signals back that rename has become blocked.

bool	unblock (ThreadID tid)
	Switches rename to unblocking if the skid buffer is empty, and signals back that rename has unblocked.

void	doSquash (const InstSeqNum &squash_seq_num, ThreadID tid)
	Executes actual squash, removing squashed instructions.

void	removeFromHistory (InstSeqNum inst_seq_num, ThreadID tid)
	Removes a committed instruction's rename history.

void	renameSrcRegs (const DynInstPtr &inst, ThreadID tid)
	Renames the source registers of an instruction.

void	renameDestRegs (const DynInstPtr &inst, ThreadID tid)
	Renames the destination registers of an instruction.

int	calcFreeROBEntries (ThreadID tid)
	Calculates the number of free ROB entries for a specific thread.

int	calcFreeIQEntries (ThreadID tid)
	Calculates the number of free IQ entries for a specific thread.

int	calcFreeLQEntries (ThreadID tid)
	Calculates the number of free LQ entries for a specific thread.

int	calcFreeSQEntries (ThreadID tid)
	Calculates the number of free SQ entries for a specific thread.

unsigned	validInsts ()
	Returns the number of valid instructions coming from decode.

void	readStallSignals (ThreadID tid)
	Reads signals telling rename to block/unblock.

bool	checkStall (ThreadID tid)
	Checks if any stages are telling rename to block.

void	readFreeEntries (ThreadID tid)
	Gets the number of free entries for a specific thread.

bool	checkSignalsAndUpdate (ThreadID tid)
	Checks the signals and updates the status.

void	serializeAfter (InstQueue &inst_list, ThreadID tid)
	Either serializes on the next instruction available in the InstQueue, or records that it must serialize on the next instruction to enter rename.

void	incrFullStat (const FullSource &source)
	Function used to increment the stat that corresponds to the source of the stall.

Private Attributes
RenameStatus	_status
	Rename status.

ThreadStatus	renameStatus [MaxThreads]
	Per-thread status.

ProbePointArg< DynInstPtr > *	ppRename
	To probe when register renaming for an instruction is complete.

ProbePointArg< SeqNumRegPair > *	ppSquashInRename
	To probe when an instruction is squashed and the register mapping for it needs to be undone.

IEW *	iew_ptr
	Pointer to IEW stage.

Commit *	commit_ptr
	Pointer to commit stage.

std::list< RenameHistory >	historyBuffer [MaxThreads]
	A per-thread list of all destination register renames, used to either undo rename mappings or free old physical registers.

CPU *	cpu
	Pointer to CPU.

TimeBuffer< TimeStruct > *	timeBuffer
	Pointer to main time buffer used for backwards communication.

TimeBuffer< TimeStruct >::wire	fromIEW
	Wire to get IEW's output from backwards time buffer.

TimeBuffer< TimeStruct >::wire	fromCommit
	Wire to get commit's output from backwards time buffer.

TimeBuffer< TimeStruct >::wire	toDecode
	Wire to write infromation heading to previous stages.

TimeBuffer< RenameStruct > *	renameQueue
	Rename instruction queue.

TimeBuffer< RenameStruct >::wire	toIEW
	Wire to write any information heading to IEW.

TimeBuffer< DecodeStruct > *	decodeQueue
	Decode instruction queue interface.

TimeBuffer< DecodeStruct >::wire	fromDecode
	Wire to get decode's output from decode queue.

InstQueue	insts [MaxThreads]
	Queue of all instructions coming from decode this cycle.

InstQueue	skidBuffer [MaxThreads]
	Skid buffer between rename and decode.

UnifiedRenameMap *	renameMap [MaxThreads]
	Rename map interface.

UnifiedFreeList *	freeList
	Free list interface.

std::vector< PhysRegIdPtr >	freeingInProgress [MaxThreads]
	Hold phys regs to be released after squash finish.

std::list< ThreadID > *	activeThreads
	Pointer to the list of active threads.

Scoreboard *	scoreboard
	Pointer to the scoreboard.

int	instsInProgress [MaxThreads]
	Count of instructions in progress that have been sent off to the IQ and ROB, but are not yet included in their occupancy counts.

int	loadsInProgress [MaxThreads]
	Count of Load instructions in progress that have been sent off to the IQ and ROB, but are not yet included in their occupancy counts.

int	storesInProgress [MaxThreads]
	Count of Store instructions in progress that have been sent off to the IQ and ROB, but are not yet included in their occupancy counts.

bool	wroteToTimeBuffer
	Variable that tracks if decode has written to the time buffer this cycle.

FreeEntries	freeEntries [MaxThreads]
	Per-thread tracking of the number of free entries of back-end structures.

bool	emptyROB [MaxThreads]
	Records if the ROB is empty.

Stalls	stalls [MaxThreads]
	Tracks which stages are telling decode to stall.

DynInstPtr	serializeInst [MaxThreads]
	The serialize instruction that rename has stalled on.

bool	serializeOnNextInst [MaxThreads]
	Records if rename needs to serialize on the next instruction for any thread.

int	iewToRenameDelay
	Delay between iew and rename, in ticks.

int	decodeToRenameDelay
	Delay between decode and rename, in ticks.

unsigned	commitToRenameDelay
	Delay between commit and rename, in ticks.

unsigned	renameWidth
	Rename width, in instructions.

unsigned	toIEWIndex
	The index of the instruction in the time buffer to IEW that rename is currently using.

bool	blockThisCycle
	Whether or not rename needs to block this cycle.

bool	resumeSerialize
	Whether or not rename needs to resume a serialize instruction after squashing.

bool	resumeUnblocking
	Whether or not rename needs to resume clearing out the skidbuffer after squashing.

ThreadID	numThreads
	The number of threads active in rename.

unsigned	skidBufferMax
	The maximum skid buffer size.

gem5::o3::Rename::RenameStats	stats

Detailed Description

Rename handles both single threaded and SMT rename.

Its width is specified by the parameters; each cycle it tries to rename that many instructions. It holds onto the rename history of all instructions with destination registers, storing the arch. register, the new physical register, and the old physical register, to allow for undoing of mappings if squashing happens, or freeing up registers upon commit. Rename handles blocking if the ROB, IQ, or LSQ is going to be full. Rename also handles barriers, and does so by stalling on the instruction until the ROB is empty and there are no instructions in flight to the ROB.

Definition at line 78 of file rename.hh.

Member Typedef Documentation

◆ InstQueue

typedef std::deque<DynInstPtr> gem5::o3::Rename::InstQueue

Definition at line 85 of file rename.hh.

◆ SeqNumRegPair

typedef std::pair<InstSeqNum, PhysRegIdPtr> gem5::o3::Rename::SeqNumRegPair

private

Probe points.

Definition at line 117 of file rename.hh.

Member Enumeration Documentation

◆ FullSource

enum gem5::o3::Rename::FullSource

private

Enum to record the source of a structure full stall.

Can come from either ROB, IQ, LSQ, and it is priortized in that order.

Enumerator
ROB
IQ
LQ
SQ
NONE

Definition at line 468 of file rename.hh.

◆ RenameStatus

enum gem5::o3::Rename::RenameStatus

Overall rename status.

Used to determine if the CPU can deschedule itself due to a lack of activity.

Enumerator
Active
Inactive

Definition at line 91 of file rename.hh.

◆ ThreadStatus

enum gem5::o3::Rename::ThreadStatus

Individual thread status.

Enumerator
Running
Idle
StartSquash
Squashing
Blocked
Unblocking
SerializeStall

Definition at line 98 of file rename.hh.

Constructor & Destructor Documentation

◆ Rename()

gem5::o3::Rename::Rename	(	CPU *	_cpu,
		const BaseO3CPUParams &	params )

Rename constructor.

Definition at line 61 of file rename.cc.

References decodeToRenameDelay, emptyROB, fatal, freeEntries, Idle, instsInProgress, loadsInProgress, gem5::o3::MaxThreads, gem5::o3::MaxWidth, renameMap, renameStatus, renameWidth, serializeInst, serializeOnNextInst, skidBufferMax, stalls, and storesInProgress.

Member Function Documentation

◆ block()

bool gem5::o3::Rename::block ( ThreadID tid )

private

Switches rename to blocking, and signals back that rename has become blocked.

Returns: Returns true if there is a status change.

Definition at line 862 of file rename.cc.

References Blocked, DPRINTF, renameStatus, resumeUnblocking, SerializeStall, skidInsert(), toDecode, Unblocking, and wroteToTimeBuffer.

Referenced by checkSignalsAndUpdate(), rename(), and renameInsts().

◆ calcFreeIQEntries()

int gem5::o3::Rename::calcFreeIQEntries ( ThreadID tid )

private

Calculates the number of free IQ entries for a specific thread.

Definition at line 1150 of file rename.cc.

References freeEntries, fromIEW, instsInProgress, and gem5::o3::Rename::FreeEntries::iqEntries.

Referenced by checkStall(), and renameInsts().

◆ calcFreeLQEntries()

int gem5::o3::Rename::calcFreeLQEntries ( ThreadID tid )

private

Calculates the number of free LQ entries for a specific thread.

Definition at line 1161 of file rename.cc.

References DPRINTF, freeEntries, fromIEW, loadsInProgress, and gem5::o3::Rename::FreeEntries::lqEntries.

Referenced by checkStall(), and renameInsts().

◆ calcFreeROBEntries()

int gem5::o3::Rename::calcFreeROBEntries ( ThreadID tid )

private

Calculates the number of free ROB entries for a specific thread.

Definition at line 1139 of file rename.cc.

References freeEntries, fromIEW, instsInProgress, and gem5::o3::Rename::FreeEntries::robEntries.

Referenced by checkStall(), and renameInsts().

◆ calcFreeSQEntries()

int gem5::o3::Rename::calcFreeSQEntries ( ThreadID tid )

private

Calculates the number of free SQ entries for a specific thread.

Definition at line 1174 of file rename.cc.

References DPRINTF, freeEntries, fromIEW, gem5::o3::Rename::FreeEntries::sqEntries, and storesInProgress.

Referenced by checkStall(), and renameInsts().

◆ checkSignalsAndUpdate()

bool gem5::o3::Rename::checkSignalsAndUpdate ( ThreadID tid )

private

Checks the signals and updates the status.

Definition at line 1277 of file rename.cc.

References gem5::o3::UnifiedFreeList::addReg(), block(), Blocked, checkStall(), DPRINTF, freeingInProgress, freeList, fromCommit, insts, readFreeEntries(), readStallSignals(), renameStatus, resumeSerialize, resumeUnblocking, Running, serializeInst, SerializeStall, skidBuffer, squash(), Squashing, unblock(), and Unblocking.

Referenced by tick().

◆ checkStall()

bool gem5::o3::Rename::checkStall ( ThreadID tid )

private

Checks if any stages are telling rename to block.

Definition at line 1212 of file rename.cc.

References calcFreeIQEntries(), calcFreeLQEntries(), calcFreeROBEntries(), calcFreeSQEntries(), DPRINTF, emptyROB, instsInProgress, renameStatus, SerializeStall, and stalls.

Referenced by checkSignalsAndUpdate().

◆ clearStates()

void gem5::o3::Rename::clearStates ( ThreadID tid )

Clear all thread-specific states.

Definition at line 230 of file rename.cc.

References commit_ptr, emptyROB, freeEntries, Idle, gem5::o3::Rename::Stalls::iew, iew_ptr, gem5::o3::IEW::instQueue, instsInProgress, gem5::o3::Rename::FreeEntries::iqEntries, gem5::o3::IEW::ldstQueue, loadsInProgress, gem5::o3::Rename::FreeEntries::lqEntries, gem5::o3::InstructionQueue::numFreeEntries(), gem5::o3::LSQ::numFreeLoadEntries(), gem5::o3::LSQ::numFreeStoreEntries(), gem5::o3::Commit::numROBFreeEntries(), renameStatus, gem5::o3::Rename::FreeEntries::robEntries, serializeInst, serializeOnNextInst, gem5::o3::Rename::FreeEntries::sqEntries, stalls, and storesInProgress.

Referenced by gem5::o3::CPU::removeThread().

◆ doSquash()

void gem5::o3::Rename::doSquash	(	const InstSeqNum &	squash_seq_num,
		ThreadID	tid )

private

Executes actual squash, removing squashed instructions.

Definition at line 915 of file rename.cc.

References DPRINTF, freeingInProgress, historyBuffer, ppSquashInRename, renameMap, gem5::o3::UnifiedRenameMap::setEntry(), stats, and gem5::o3::Rename::RenameStats::undoneMaps.

Referenced by squash().

◆ drainSanityCheck()

void gem5::o3::Rename::drainSanityCheck ( ) const

Perform sanity checks after a drain.

Definition at line 328 of file rename.cc.

References historyBuffer, insts, instsInProgress, numThreads, and skidBuffer.

Referenced by gem5::o3::CPU::drainSanityCheck().

◆ dumpHistory()

void gem5::o3::Rename::dumpHistory ( )

Debugging function used to dump history buffer of renamings.

Definition at line 1423 of file rename.cc.

References gem5::cprintf(), historyBuffer, and numThreads.

◆ incrFullStat()

void gem5::o3::Rename::incrFullStat ( const FullSource & source )

private

Function used to increment the stat that corresponds to the source of the stall.

Definition at line 1401 of file rename.cc.

References IQ, gem5::o3::Rename::RenameStats::IQFullEvents, LQ, gem5::o3::Rename::RenameStats::LQFullEvents, panic, ROB, gem5::o3::Rename::RenameStats::ROBFullEvents, SQ, gem5::o3::Rename::RenameStats::SQFullEvents, and stats.

Referenced by renameInsts().

◆ isDrained()

bool gem5::o3::Rename::isDrained ( ) const

Has the stage drained?

Definition at line 308 of file rename.cc.

References historyBuffer, Idle, insts, instsInProgress, numThreads, renameStatus, Running, and skidBuffer.

Referenced by gem5::o3::CPU::isCpuDrained().

◆ name()

std::string gem5::o3::Rename::name ( ) const

Returns the name of rename.

Definition at line 92 of file rename.cc.

References cpu, and gem5::Named::name().

◆ readFreeEntries()

void gem5::o3::Rename::readFreeEntries ( ThreadID tid )

private

Gets the number of free entries for a specific thread.

Definition at line 1240 of file rename.cc.

References gem5::CCRegClass, DPRINTF, emptyROB, gem5::FloatRegClass, freeEntries, fromCommit, fromIEW, instsInProgress, gem5::IntRegClass, gem5::o3::Rename::FreeEntries::iqEntries, gem5::o3::Rename::FreeEntries::lqEntries, gem5::MatRegClass, renameMap, gem5::o3::Rename::FreeEntries::robEntries, gem5::o3::Rename::FreeEntries::sqEntries, gem5::VecElemClass, gem5::VecPredRegClass, and gem5::VecRegClass.

Referenced by checkSignalsAndUpdate().

◆ readStallSignals()

void gem5::o3::Rename::readStallSignals ( ThreadID tid )

private

Reads signals telling rename to block/unblock.

Definition at line 1199 of file rename.cc.

References fromIEW, gem5::o3::Rename::Stalls::iew, and stalls.

Referenced by checkSignalsAndUpdate().

◆ regProbePoints()

void gem5::o3::Rename::regProbePoints ( )

Registers probes.

Definition at line 182 of file rename.cc.

References cpu, gem5::SimObject::getProbeManager(), ppRename, and ppSquashInRename.

Referenced by gem5::o3::CPU::regProbePoints().

◆ removeFromHistory()

void gem5::o3::Rename::removeFromHistory	(	InstSeqNum	inst_seq_num,
		ThreadID	tid )

private

Removes a committed instruction's rename history.

Definition at line 963 of file rename.cc.

References gem5::o3::UnifiedFreeList::addReg(), gem5::o3::Rename::RenameStats::committedMaps, DPRINTF, freeList, historyBuffer, and stats.

Referenced by tick().

◆ rename()

void gem5::o3::Rename::rename	(	bool &	status_change,
		ThreadID	tid )

private

Determines what to do based on rename's current status.

Parameters

status_change	rename() sets this variable if there was a status change (ie switching from blocking to unblocking).
tid	Thread id to rename instructions from.

Definition at line 455 of file rename.cc.

References block(), gem5::o3::Rename::RenameStats::blockCycles, Blocked, blockThisCycle, DPRINTF, Idle, renameInsts(), renameStatus, resumeSerialize, resumeUnblocking, Running, SerializeStall, gem5::o3::Rename::RenameStats::serializeStallCycles, skidInsert(), gem5::o3::Rename::RenameStats::squashCycles, Squashing, stats, toDecode, unblock(), Unblocking, and validInsts().

Referenced by tick().

◆ renameDestRegs()

void gem5::o3::Rename::renameDestRegs	(	const DynInstPtr &	inst,
		ThreadID	tid )

private

Renames the destination registers of an instruction.

Definition at line 1085 of file rename.cc.

References gem5::RegId::className(), DPRINTF, gem5::RegId::flatten(), gem5::ThreadContext::getIsaPtr(), gem5::RegId::getNumPinnedWrites(), historyBuffer, gem5::RegId::index(), gem5::o3::Rename::RenameStats::renamedOperands, renameMap, scoreboard, gem5::RegId::setNumPinnedWrites(), stats, and gem5::o3::Scoreboard::unsetReg().

Referenced by renameInsts().

◆ renameInsts()

void gem5::o3::Rename::renameInsts ( ThreadID tid )

private

Renames instructions for the given thread.

Also handles serializing instructions.

Definition at line 510 of file rename.cc.

Referenced by rename().

◆ renameSrcRegs()

void gem5::o3::Rename::renameSrcRegs	(	const DynInstPtr &	inst,
		ThreadID	tid )

private

Renames the source registers of an instruction.

Definition at line 1012 of file rename.cc.

References gem5::CCRegClass, gem5::PhysRegId::className(), gem5::RegId::className(), gem5::RegId::classValue(), DPRINTF, gem5::PhysRegId::flatIndex(), gem5::RegId::flatten(), gem5::FloatRegClass, gem5::o3::Rename::RenameStats::fpLookups, gem5::ThreadContext::getIsaPtr(), gem5::o3::Scoreboard::getReg(), gem5::PhysRegId::index(), gem5::RegId::index(), gem5::o3::Rename::RenameStats::intLookups, gem5::IntRegClass, gem5::InvalidRegClass, gem5::o3::Rename::RenameStats::lookups, gem5::o3::Rename::RenameStats::matLookups, gem5::MatRegClass, gem5::MiscRegClass, panic, renameMap, scoreboard, stats, gem5::VecElemClass, gem5::o3::Rename::RenameStats::vecLookups, gem5::o3::Rename::RenameStats::vecPredLookups, gem5::VecPredRegClass, and gem5::VecRegClass.

Referenced by renameInsts().

◆ resetStage()

void gem5::o3::Rename::resetStage ( )

private

◆ serializeAfter()

void gem5::o3::Rename::serializeAfter	(	InstQueue &	inst_list,
		ThreadID	tid )

private

Either serializes on the next instruction available in the InstQueue, or records that it must serialize on the next instruction to enter rename.

Parameters

inst_list	The list of younger, unprocessed instructions for the thread that has the serializeAfter instruction.
tid	The thread id.

Definition at line 1388 of file rename.cc.

References serializeOnNextInst.

Referenced by renameInsts().

◆ setActiveThreads()

void gem5::o3::Rename::setActiveThreads ( std::list< ThreadID > * at_ptr )

Sets pointer to list of active threads.

Definition at line 282 of file rename.cc.

References activeThreads.

◆ setCommitStage()

void gem5::o3::Rename::setCommitStage ( Commit * commit_stage )

inline

Sets pointer to commit stage.

Used only for initialization.

Definition at line 150 of file rename.hh.

References commit_ptr.

◆ setDecodeQueue()

void gem5::o3::Rename::setDecodeQueue ( TimeBuffer< DecodeStruct > * dq_ptr )

Sets pointer to time buffer coming from decode.

Definition at line 215 of file rename.cc.

References decodeQueue, decodeToRenameDelay, fromDecode, and gem5::TimeBuffer< T >::getWire().

◆ setFreeList()

void gem5::o3::Rename::setFreeList ( UnifiedFreeList * fl_ptr )

Sets pointer to the free list.

Definition at line 296 of file rename.cc.

References freeList.

◆ setIEWStage()

void gem5::o3::Rename::setIEWStage ( IEW * iew_stage )

inline

Sets pointer to IEW stage.

Used only for initialization.

Definition at line 146 of file rename.hh.

References iew_ptr.

◆ setRenameMap()

void gem5::o3::Rename::setRenameMap ( UnifiedRenameMap::PerThreadUnifiedRenameMap & rm_ptr )

Sets pointer to rename maps (per-thread structures).

Definition at line 289 of file rename.cc.

References numThreads, and renameMap.

◆ setRenameQueue()

void gem5::o3::Rename::setRenameQueue ( TimeBuffer< RenameStruct > * rq_ptr )

Sets pointer to time buffer used to communicate to the next stage.

Definition at line 206 of file rename.cc.

References gem5::TimeBuffer< T >::getWire(), renameQueue, and toIEW.

◆ setScoreboard()

void gem5::o3::Rename::setScoreboard ( Scoreboard * _scoreboard )

Sets pointer to the scoreboard.

Definition at line 302 of file rename.cc.

References scoreboard.

◆ setTimeBuffer()

void gem5::o3::Rename::setTimeBuffer ( TimeBuffer< TimeStruct > * tb_ptr )

Sets the main backwards communication time buffer pointer.

Definition at line 191 of file rename.cc.

References commitToRenameDelay, fromCommit, fromIEW, gem5::TimeBuffer< T >::getWire(), iewToRenameDelay, timeBuffer, and toDecode.

◆ skidInsert()

void gem5::o3::Rename::skidInsert ( ThreadID tid )

private

Inserts unused instructions from a given thread into the skid buffer, to be renamed once rename unblocks.

Definition at line 760 of file rename.cc.

References DPRINTF, insts, panic, skidBuffer, skidBufferMax, gem5::o3::Rename::RenameStats::skidInsts, stats, and warn.

Referenced by block(), and rename().

◆ skidsEmpty()

bool gem5::o3::Rename::skidsEmpty ( )

private

Returns if all of the skid buffers are empty.

Definition at line 808 of file rename.cc.

References activeThreads, and skidBuffer.

◆ sortInsts()

void gem5::o3::Rename::sortInsts ( )

private

Separates instructions from decode into individual lists of instructions sorted by thread.

Definition at line 793 of file rename.cc.

References gem5::curTick(), fromDecode, gem5::ArmISA::i, and insts.

Referenced by tick().

◆ squash()

void gem5::o3::Rename::squash	(	const InstSeqNum &	squash_seq_num,
		ThreadID	tid )

Squashes all instructions in a thread.

Definition at line 339 of file rename.cc.

References Blocked, doSquash(), DPRINTF, fromDecode, gem5::ArmISA::i, insts, renameStatus, resumeSerialize, serializeInst, SerializeStall, skidBuffer, Squashing, toDecode, Unblocking, and wroteToTimeBuffer.

Referenced by checkSignalsAndUpdate().

◆ startupStage()

void gem5::o3::Rename::startupStage ( )

Initializes variables for the stage.

Definition at line 224 of file rename.cc.

References resetStage().

Referenced by gem5::o3::CPU::startup().

◆ takeOverFrom()

void gem5::o3::Rename::takeOverFrom ( )

Takes over from another CPU's thread.

Definition at line 322 of file rename.cc.

References resetStage().

Referenced by gem5::o3::CPU::takeOverFrom().

◆ tick()

void gem5::o3::Rename::tick ( )

Ticks rename, which processes all input signals and attempts to rename as many instructions as possible.

Definition at line 392 of file rename.cc.

References activeThreads, gem5::o3::CPU::activityThisCycle(), blockThisCycle, checkSignalsAndUpdate(), cpu, DPRINTF, fromCommit, fromIEW, instsInProgress, loadsInProgress, numThreads, removeFromHistory(), rename(), renameStatus, sortInsts(), Squashing, storesInProgress, toIEWIndex, updateStatus(), and wroteToTimeBuffer.

Referenced by gem5::o3::CPU::tick().

◆ unblock()

bool gem5::o3::Rename::unblock ( ThreadID tid )

private

Switches rename to unblocking if the skid buffer is empty, and signals back that rename has unblocked.

Returns: Returns true if there is a status change.

Definition at line 895 of file rename.cc.

References DPRINTF, renameStatus, Running, SerializeStall, skidBuffer, toDecode, and wroteToTimeBuffer.

Referenced by checkSignalsAndUpdate(), and rename().

◆ updateStatus()

void gem5::o3::Rename::updateStatus ( )

private

Updates overall rename status based on all of the threads' statuses.

Definition at line 824 of file rename.cc.

References _status, gem5::o3::CPU::activateStage(), Active, activeThreads, cpu, gem5::o3::CPU::deactivateStage(), DPRINTF, Inactive, gem5::o3::CPU::RenameIdx, renameStatus, and Unblocking.

Referenced by tick().

◆ validInsts()

unsigned gem5::o3::Rename::validInsts ( )

private

Returns the number of valid instructions coming from decode.

Definition at line 1186 of file rename.cc.

References fromDecode, and gem5::ArmISA::i.

Referenced by rename().

Member Data Documentation

◆ _status

RenameStatus gem5::o3::Rename::_status

private

Rename status.

Definition at line 111 of file rename.hh.

Referenced by resetStage(), and updateStatus().

◆ activeThreads

std::list<ThreadID>* gem5::o3::Rename::activeThreads

private

Pointer to the list of active threads.

Definition at line 366 of file rename.hh.

Referenced by setActiveThreads(), skidsEmpty(), tick(), and updateStatus().

◆ blockThisCycle

bool gem5::o3::Rename::blockThisCycle

private

Whether or not rename needs to block this cycle.

Definition at line 449 of file rename.hh.

Referenced by rename(), renameInsts(), and tick().

◆ commit_ptr

Commit* gem5::o3::Rename::commit_ptr

private

Pointer to commit stage.

Used only for initialization.

Definition at line 160 of file rename.hh.

Referenced by clearStates(), resetStage(), and setCommitStage().

◆ commitToRenameDelay

unsigned gem5::o3::Rename::commitToRenameDelay

private

Delay between commit and rename, in ticks.

Definition at line 438 of file rename.hh.

Referenced by setTimeBuffer().

◆ cpu

CPU* gem5::o3::Rename::cpu

private

Pointer to CPU.

Definition at line 324 of file rename.hh.

Referenced by name(), regProbePoints(), tick(), and updateStatus().

◆ decodeQueue

TimeBuffer<DecodeStruct>* gem5::o3::Rename::decodeQueue

private

Decode instruction queue interface.

Definition at line 345 of file rename.hh.

Referenced by setDecodeQueue().

◆ decodeToRenameDelay

int gem5::o3::Rename::decodeToRenameDelay

private

Delay between decode and rename, in ticks.

Definition at line 435 of file rename.hh.

Referenced by Rename(), and setDecodeQueue().

◆ emptyROB

bool gem5::o3::Rename::emptyROB[MaxThreads]

private

Records if the ROB is empty.

In SMT mode the ROB may be dynamically partitioned between threads, so the ROB must tell rename when it is empty.

Definition at line 411 of file rename.hh.

Referenced by checkStall(), clearStates(), readFreeEntries(), Rename(), renameInsts(), and resetStage().

◆ freeEntries

FreeEntries gem5::o3::Rename::freeEntries[MaxThreads]

private

Per-thread tracking of the number of free entries of back-end structures.

Definition at line 405 of file rename.hh.

Referenced by calcFreeIQEntries(), calcFreeLQEntries(), calcFreeROBEntries(), calcFreeSQEntries(), clearStates(), readFreeEntries(), Rename(), and resetStage().

◆ freeingInProgress

std::vector<PhysRegIdPtr> gem5::o3::Rename::freeingInProgress[MaxThreads]

private

Hold phys regs to be released after squash finish.

Definition at line 363 of file rename.hh.

Referenced by checkSignalsAndUpdate(), and doSquash().

◆ freeList

UnifiedFreeList* gem5::o3::Rename::freeList

private

Free list interface.

Definition at line 360 of file rename.hh.

Referenced by checkSignalsAndUpdate(), removeFromHistory(), and setFreeList().

◆ fromCommit

TimeBuffer<TimeStruct>::wire gem5::o3::Rename::fromCommit

private

Wire to get commit's output from backwards time buffer.

Definition at line 333 of file rename.hh.

Referenced by checkSignalsAndUpdate(), readFreeEntries(), setTimeBuffer(), and tick().

◆ fromDecode

TimeBuffer<DecodeStruct>::wire gem5::o3::Rename::fromDecode

private

Wire to get decode's output from decode queue.

Definition at line 348 of file rename.hh.

Referenced by setDecodeQueue(), sortInsts(), squash(), and validInsts().

◆ fromIEW

TimeBuffer<TimeStruct>::wire gem5::o3::Rename::fromIEW

private

Wire to get IEW's output from backwards time buffer.

Definition at line 330 of file rename.hh.

Referenced by calcFreeIQEntries(), calcFreeLQEntries(), calcFreeROBEntries(), calcFreeSQEntries(), readFreeEntries(), readStallSignals(), renameInsts(), setTimeBuffer(), and tick().

◆ historyBuffer

std::list<RenameHistory> gem5::o3::Rename::historyBuffer[MaxThreads]

private

A per-thread list of all destination register renames, used to either undo rename mappings or free old physical registers.

Definition at line 321 of file rename.hh.

Referenced by doSquash(), drainSanityCheck(), dumpHistory(), isDrained(), removeFromHistory(), and renameDestRegs().

◆ iew_ptr

IEW* gem5::o3::Rename::iew_ptr

private

Pointer to IEW stage.

Used only for initialization.

Definition at line 157 of file rename.hh.

Referenced by clearStates(), resetStage(), and setIEWStage().

◆ iewToRenameDelay

int gem5::o3::Rename::iewToRenameDelay

private

Delay between iew and rename, in ticks.

Definition at line 432 of file rename.hh.

Referenced by setTimeBuffer().

◆ insts

InstQueue gem5::o3::Rename::insts[MaxThreads]

private

Queue of all instructions coming from decode this cycle.

Definition at line 351 of file rename.hh.

Referenced by checkSignalsAndUpdate(), drainSanityCheck(), isDrained(), renameInsts(), skidInsert(), sortInsts(), and squash().

◆ instsInProgress

int gem5::o3::Rename::instsInProgress[MaxThreads]

private

Count of instructions in progress that have been sent off to the IQ and ROB, but are not yet included in their occupancy counts.

Definition at line 374 of file rename.hh.

Referenced by calcFreeIQEntries(), calcFreeROBEntries(), checkStall(), clearStates(), drainSanityCheck(), isDrained(), readFreeEntries(), Rename(), renameInsts(), resetStage(), and tick().

◆ loadsInProgress

int gem5::o3::Rename::loadsInProgress[MaxThreads]

private

Count of Load instructions in progress that have been sent off to the IQ and ROB, but are not yet included in their occupancy counts.

Definition at line 379 of file rename.hh.

Referenced by calcFreeLQEntries(), clearStates(), Rename(), renameInsts(), resetStage(), and tick().

◆ numThreads

ThreadID gem5::o3::Rename::numThreads

private

The number of threads active in rename.

Definition at line 460 of file rename.hh.

Referenced by drainSanityCheck(), dumpHistory(), isDrained(), resetStage(), setRenameMap(), and tick().

◆ ppRename

ProbePointArg<DynInstPtr>* gem5::o3::Rename::ppRename

private

To probe when register renaming for an instruction is complete.

Definition at line 119 of file rename.hh.

Referenced by regProbePoints(), and renameInsts().

◆ ppSquashInRename

ProbePointArg<SeqNumRegPair>* gem5::o3::Rename::ppSquashInRename

private

To probe when an instruction is squashed and the register mapping for it needs to be undone.

Definition at line 124 of file rename.hh.

Referenced by doSquash(), and regProbePoints().

◆ renameMap

UnifiedRenameMap* gem5::o3::Rename::renameMap[MaxThreads]

private

Rename map interface.

Definition at line 357 of file rename.hh.

Referenced by doSquash(), readFreeEntries(), Rename(), renameDestRegs(), renameInsts(), renameSrcRegs(), and setRenameMap().

◆ renameQueue

TimeBuffer<RenameStruct>* gem5::o3::Rename::renameQueue

private

Rename instruction queue.

Definition at line 339 of file rename.hh.

Referenced by setRenameQueue().

◆ renameStatus

ThreadStatus gem5::o3::Rename::renameStatus[MaxThreads]

private

Per-thread status.

Definition at line 114 of file rename.hh.

Referenced by block(), checkSignalsAndUpdate(), checkStall(), clearStates(), isDrained(), Rename(), rename(), renameInsts(), resetStage(), squash(), tick(), unblock(), and updateStatus().

◆ renameWidth

unsigned gem5::o3::Rename::renameWidth

private

Rename width, in instructions.

Definition at line 441 of file rename.hh.

Referenced by Rename(), and renameInsts().

◆ resumeSerialize

bool gem5::o3::Rename::resumeSerialize

private

Whether or not rename needs to resume a serialize instruction after squashing.

Definition at line 453 of file rename.hh.

Referenced by checkSignalsAndUpdate(), rename(), resetStage(), and squash().

◆ resumeUnblocking

bool gem5::o3::Rename::resumeUnblocking

private

Whether or not rename needs to resume clearing out the skidbuffer after squashing.

Definition at line 457 of file rename.hh.

Referenced by block(), checkSignalsAndUpdate(), rename(), and resetStage().

◆ scoreboard

Scoreboard* gem5::o3::Rename::scoreboard

private

Pointer to the scoreboard.

Definition at line 369 of file rename.hh.

Referenced by renameDestRegs(), renameSrcRegs(), and setScoreboard().

◆ serializeInst

DynInstPtr gem5::o3::Rename::serializeInst[MaxThreads]

private

The serialize instruction that rename has stalled on.

Definition at line 424 of file rename.hh.

Referenced by checkSignalsAndUpdate(), clearStates(), Rename(), renameInsts(), resetStage(), and squash().

◆ serializeOnNextInst

bool gem5::o3::Rename::serializeOnNextInst[MaxThreads]

private

Records if rename needs to serialize on the next instruction for any thread.

Definition at line 429 of file rename.hh.

Referenced by clearStates(), Rename(), renameInsts(), resetStage(), and serializeAfter().

◆ skidBuffer

InstQueue gem5::o3::Rename::skidBuffer[MaxThreads]

private

Skid buffer between rename and decode.

Definition at line 354 of file rename.hh.

Referenced by checkSignalsAndUpdate(), drainSanityCheck(), isDrained(), renameInsts(), skidInsert(), skidsEmpty(), squash(), and unblock().

◆ skidBufferMax

unsigned gem5::o3::Rename::skidBufferMax

private

The maximum skid buffer size.

Definition at line 463 of file rename.hh.

Referenced by Rename(), and skidInsert().

◆ stalls

Stalls gem5::o3::Rename::stalls[MaxThreads]

private

Tracks which stages are telling decode to stall.

Definition at line 421 of file rename.hh.

Referenced by checkStall(), clearStates(), readStallSignals(), Rename(), and resetStage().

◆ stats

gem5::o3::Rename::RenameStats gem5::o3::Rename::stats

private

Referenced by doSquash(), incrFullStat(), removeFromHistory(), rename(), renameDestRegs(), renameInsts(), renameSrcRegs(), and skidInsert().

◆ storesInProgress

int gem5::o3::Rename::storesInProgress[MaxThreads]

private

Count of Store instructions in progress that have been sent off to the IQ and ROB, but are not yet included in their occupancy counts.

Definition at line 384 of file rename.hh.

Referenced by calcFreeSQEntries(), clearStates(), Rename(), renameInsts(), resetStage(), and tick().

◆ timeBuffer

TimeBuffer<TimeStruct>* gem5::o3::Rename::timeBuffer

private

Pointer to main time buffer used for backwards communication.

Definition at line 327 of file rename.hh.

Referenced by setTimeBuffer().

◆ toDecode

TimeBuffer<TimeStruct>::wire gem5::o3::Rename::toDecode

private

Wire to write infromation heading to previous stages.

Definition at line 336 of file rename.hh.

Referenced by block(), rename(), renameInsts(), setTimeBuffer(), squash(), and unblock().

◆ toIEW

TimeBuffer<RenameStruct>::wire gem5::o3::Rename::toIEW

private

Wire to write any information heading to IEW.

Definition at line 342 of file rename.hh.

Referenced by renameInsts(), and setRenameQueue().

◆ toIEWIndex

unsigned gem5::o3::Rename::toIEWIndex

private

The index of the instruction in the time buffer to IEW that rename is currently using.

Definition at line 446 of file rename.hh.

Referenced by renameInsts(), and tick().

◆ wroteToTimeBuffer

bool gem5::o3::Rename::wroteToTimeBuffer

private

Variable that tracks if decode has written to the time buffer this cycle.

Used to tell CPU if there is activity this cycle.

Definition at line 389 of file rename.hh.

Referenced by block(), renameInsts(), squash(), tick(), and unblock().

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

cpu/o3/rename.hh
cpu/o3/rename.cc

Classes

Public Types

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ InstQueue

◆ SeqNumRegPair

Member Enumeration Documentation

◆ FullSource

◆ RenameStatus

◆ ThreadStatus

Constructor & Destructor Documentation

◆ Rename()

Member Function Documentation

◆ block()

◆ calcFreeIQEntries()

◆ calcFreeLQEntries()

◆ calcFreeROBEntries()

◆ calcFreeSQEntries()

◆ checkSignalsAndUpdate()

◆ checkStall()

◆ clearStates()

◆ doSquash()

◆ drainSanityCheck()

◆ dumpHistory()

◆ incrFullStat()

◆ isDrained()

◆ name()

◆ readFreeEntries()

◆ readStallSignals()

◆ regProbePoints()

◆ removeFromHistory()

◆ rename()

◆ renameDestRegs()

◆ renameInsts()

◆ renameSrcRegs()

◆ resetStage()

◆ serializeAfter()

◆ setActiveThreads()

◆ setCommitStage()

◆ setDecodeQueue()

◆ setFreeList()

◆ setIEWStage()

◆ setRenameMap()

◆ setRenameQueue()

◆ setScoreboard()

◆ setTimeBuffer()

◆ skidInsert()

◆ skidsEmpty()

◆ sortInsts()

◆ squash()

◆ startupStage()

◆ takeOverFrom()

◆ tick()

◆ unblock()

◆ updateStatus()

◆ validInsts()

Member Data Documentation

◆ _status

◆ activeThreads

◆ blockThisCycle

◆ commit_ptr

◆ commitToRenameDelay

◆ cpu

◆ decodeQueue

◆ decodeToRenameDelay

◆ emptyROB

◆ freeEntries

◆ freeingInProgress

◆ freeList

◆ fromCommit

◆ fromDecode

◆ fromIEW

◆ historyBuffer

◆ iew_ptr

◆ iewToRenameDelay

◆ insts