The goal of this scheduling strategy is to maximize ILP for a single wave (i.e. More...

#include "Target/AMDGPU/GCNSchedStrategy.h"

Inheritance diagram for llvm::GCNMaxILPSchedStrategy:

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Public Member Functions
	GCNMaxILPSchedStrategy (const MachineSchedContext *C)

Public Member Functions inherited from llvm::GCNSchedStrategy
	GCNSchedStrategy (const MachineSchedContext *C)

SUnit *	pickNode (bool &IsTopNode) override
	Pick the best node to balance the schedule. Implements MachineSchedStrategy.

void	initialize (ScheduleDAGMI *DAG) override
	Initialize the strategy after building the DAG for a new region.

unsigned	getTargetOccupancy ()

void	setTargetOccupancy (unsigned Occ)

GCNSchedStageID	getCurrentStage ()

bool	advanceStage ()

bool	hasNextStage () const

GCNSchedStageID	getNextStage () const

Public Member Functions inherited from llvm::GenericScheduler
	GenericScheduler (const MachineSchedContext *C)

void	initPolicy (MachineBasicBlock::iterator Begin, MachineBasicBlock::iterator End, unsigned NumRegionInstrs) override
	Initialize the per-region scheduling policy.

void	dumpPolicy () const override

bool	shouldTrackPressure () const override
	Check if pressure tracking is needed before building the DAG and initializing this strategy.

bool	shouldTrackLaneMasks () const override
	Returns true if lanemasks should be tracked.

void	initialize (ScheduleDAGMI *dag) override
	Initialize the strategy after building the DAG for a new region.

SUnit *	pickNode (bool &IsTopNode) override
	Pick the best node to balance the schedule. Implements MachineSchedStrategy.

void	schedNode (SUnit *SU, bool IsTopNode) override
	Update the scheduler's state after scheduling a node.

void	releaseTopNode (SUnit *SU) override
	When all predecessor dependencies have been resolved, free this node for top-down scheduling.

void	releaseBottomNode (SUnit *SU) override
	When all successor dependencies have been resolved, free this node for bottom-up scheduling.

void	registerRoots () override
	Notify this strategy that all roots have been released (including those that depend on EntrySU or ExitSU).

Public Member Functions inherited from llvm::MachineSchedStrategy
virtual	~MachineSchedStrategy ()=default

virtual void	initPolicy (MachineBasicBlock::iterator Begin, MachineBasicBlock::iterator End, unsigned NumRegionInstrs)
	Optionally override the per-region scheduling policy.

virtual void	dumpPolicy () const

virtual bool	shouldTrackPressure () const
	Check if pressure tracking is needed before building the DAG and initializing this strategy.

virtual bool	shouldTrackLaneMasks () const
	Returns true if lanemasks should be tracked.

virtual bool	doMBBSchedRegionsTopDown () const

virtual void	initialize (ScheduleDAGMI *DAG)=0
	Initialize the strategy after building the DAG for a new region.

virtual void	enterMBB (MachineBasicBlock *MBB)
	Tell the strategy that MBB is about to be processed.

virtual void	leaveMBB ()
	Tell the strategy that current MBB is done.

virtual void	registerRoots ()
	Notify this strategy that all roots have been released (including those that depend on EntrySU or ExitSU).

virtual SUnit *	pickNode (bool &IsTopNode)=0
	Pick the next node to schedule, or return NULL.

virtual void	scheduleTree (unsigned SubtreeID)
	Scheduler callback to notify that a new subtree is scheduled.

virtual void	schedNode (SUnit *SU, bool IsTopNode)=0
	Notify MachineSchedStrategy that ScheduleDAGMI has scheduled an instruction and updated scheduled/remaining flags in the DAG nodes.

virtual void	releaseTopNode (SUnit *SU)=0
	When all predecessor dependencies have been resolved, free this node for top-down scheduling.

virtual void	releaseBottomNode (SUnit *SU)=0
	When all successor dependencies have been resolved, free this node for bottom-up scheduling.

Protected Member Functions
bool	tryCandidate (SchedCandidate &Cand, SchedCandidate &TryCand, SchedBoundary *Zone) const override
	Apply a set of heuristics to a new candidate.

Protected Member Functions inherited from llvm::GCNSchedStrategy
SUnit *	pickNodeBidirectional (bool &IsTopNode)

void	pickNodeFromQueue (SchedBoundary &Zone, const CandPolicy &ZonePolicy, const RegPressureTracker &RPTracker, SchedCandidate &Cand, bool IsBottomUp)

void	initCandidate (SchedCandidate &Cand, SUnit SU, bool AtTop, const RegPressureTracker &RPTracker, const SIRegisterInfo SRI, unsigned SGPRPressure, unsigned VGPRPressure, bool IsBottomUp)

Protected Member Functions inherited from llvm::GenericScheduler
void	checkAcyclicLatency ()
	Set IsAcyclicLatencyLimited if the acyclic path is longer than the cyclic critical path by more cycles than it takes to drain the instruction buffer.

void	initCandidate (SchedCandidate &Cand, SUnit *SU, bool AtTop, const RegPressureTracker &RPTracker, RegPressureTracker &TempTracker)

virtual bool	tryCandidate (SchedCandidate &Cand, SchedCandidate &TryCand, SchedBoundary *Zone) const
	Apply a set of heuristics to a new candidate.

SUnit *	pickNodeBidirectional (bool &IsTopNode)
	Pick the best candidate node from either the top or bottom queue.

void	pickNodeFromQueue (SchedBoundary &Zone, const CandPolicy &ZonePolicy, const RegPressureTracker &RPTracker, SchedCandidate &Candidate)
	Pick the best candidate from the queue.

void	reschedulePhysReg (SUnit *SU, bool isTop)

Protected Member Functions inherited from llvm::GenericSchedulerBase
	GenericSchedulerBase (const MachineSchedContext *C)

void	setPolicy (CandPolicy &Policy, bool IsPostRA, SchedBoundary &CurrZone, SchedBoundary *OtherZone)
	Set the CandPolicy given a scheduling zone given the current resources and latencies inside and outside the zone.

void	traceCandidate (const SchedCandidate &Cand)

Additional Inherited Members
Public Types inherited from llvm::GenericSchedulerBase
enum	CandReason : uint8_t { NoCand , Only1 , PhysReg , RegExcess , RegCritical , Stall , Cluster , Weak , RegMax , ResourceReduce , ResourceDemand , BotHeightReduce , BotPathReduce , TopDepthReduce , TopPathReduce , NextDefUse , NodeOrder }
	Represent the type of SchedCandidate found within a single queue. More...

Static Public Member Functions inherited from llvm::GenericSchedulerBase
static const char *	getReasonStr (GenericSchedulerBase::CandReason Reason)

Public Attributes inherited from llvm::GCNSchedStrategy
bool	HasHighPressure

bool	KnownExcessRP = false

unsigned	ErrorMargin = 3

const unsigned	HighRPSGPRBias = 7

const unsigned	HighRPVGPRBias = 7

unsigned	SGPRCriticalLimit

unsigned	VGPRCriticalLimit

unsigned	SGPRLimitBias = 0

unsigned	VGPRLimitBias = 0

Protected Attributes inherited from llvm::GCNSchedStrategy
std::vector< unsigned >	Pressure

std::vector< unsigned >	MaxPressure

unsigned	SGPRExcessLimit

unsigned	VGPRExcessLimit

unsigned	TargetOccupancy

MachineFunction *	MF

SmallVector< GCNSchedStageID, 4 >	SchedStages

SmallVectorImpl< GCNSchedStageID >::iterator	CurrentStage = nullptr

Protected Attributes inherited from llvm::GenericScheduler
ScheduleDAGMILive *	DAG = nullptr

MachineSchedPolicy	RegionPolicy

SchedBoundary	Top

SchedBoundary	Bot

SchedCandidate	TopCand
	Candidate last picked from Top boundary.

SchedCandidate	BotCand
	Candidate last picked from Bot boundary.

Protected Attributes inherited from llvm::GenericSchedulerBase
const MachineSchedContext *	Context

const TargetSchedModel *	SchedModel = nullptr

const TargetRegisterInfo *	TRI = nullptr

SchedRemainder	Rem

Detailed Description

The goal of this scheduling strategy is to maximize ILP for a single wave (i.e.

latency hiding).

Definition at line 130 of file GCNSchedStrategy.h.

Constructor & Destructor Documentation

◆ GCNMaxILPSchedStrategy()

GCNMaxILPSchedStrategy::GCNMaxILPSchedStrategy ( const MachineSchedContext * C )

Definition at line 481 of file GCNSchedStrategy.cpp.

References llvm::ILPInitialSchedule, llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::GCNSchedStrategy::SchedStages.

Member Function Documentation

◆ tryCandidate()

bool GCNMaxILPSchedStrategy::tryCandidate	(	SchedCandidate &	Cand,
		SchedCandidate &	TryCand,
		SchedBoundary *	Zone
	)		const

overrideprotectedvirtual

Apply a set of heuristics to a new candidate.

Heuristics are currently hierarchical. This may be more efficient than a graduated cost model because we don't need to evaluate all aspects of the model for each node in the queue. But it's really done to make the heuristics easier to debug and statistically analyze.

Parameters

Cand	provides the policy and current best candidate.
TryCand	refers to the next SUnit candidate, otherwise uninitialized.
Zone	describes the scheduled zone that we are extending, or nullptr if Cand is from a different zone than TryCand.

Returns: true if TryCand is better than Cand (Reason is NOT NoCand)

Reimplemented from llvm::GenericScheduler.

Definition at line 486 of file GCNSchedStrategy.cpp.

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

lib/Target/AMDGPU/GCNSchedStrategy.h
lib/Target/AMDGPU/GCNSchedStrategy.cpp

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ GCNMaxILPSchedStrategy()

Member Function Documentation

◆ tryCandidate()