LLVM 22.0.0git
Public Member Functions | Public Attributes | Protected Member Functions | Protected Attributes | List of all members
llvm::GCNSchedStrategy Class Reference

This is a minimal scheduler strategy. More...

#include "Target/AMDGPU/GCNSchedStrategy.h"

Inheritance diagram for llvm::GCNSchedStrategy:
[legend]

Public Member Functions

 GCNSchedStrategy (const MachineSchedContext *C)
SUnit * pickNode (bool &IsTopNode) override
 Pick the next node to schedule, or return NULL.
void schedNode (SUnit *SU, bool IsTopNode) override
 Notify MachineSchedStrategy that ScheduleDAGMI has scheduled an instruction and updated scheduled/remaining flags in the DAG nodes.
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
GCNDownwardRPTracker * getDownwardTracker ()
GCNUpwardRPTracker * getUpwardTracker ()
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 bool doMBBSchedRegionsTopDown () const
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 scheduleTree (unsigned SubtreeID)
 Scheduler callback to notify that a new subtree is scheduled.

Public Attributes

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 Member Functions

SUnit * pickNodeBidirectional (bool &IsTopNode, bool &PickedPending)
void pickNodeFromQueue (SchedBoundary &Zone, const CandPolicy &ZonePolicy, const RegPressureTracker &RPTracker, SchedCandidate &Cand, bool &IsPending, bool IsBottomUp)
void initCandidate (SchedCandidate &Cand, SUnit *SU, bool AtTop, const RegPressureTracker &RPTracker, const SIRegisterInfo *SRI, unsigned SGPRPressure, unsigned VGPRPressure, bool IsBottomUp)
bool tryPendingCandidate (SchedCandidate &Cand, SchedCandidate &TryCand, SchedBoundary *Zone) const
 Evaluates instructions in the pending queue using a subset of scheduling heuristics.
void printCandidateDecision (const SchedCandidate &Current, const SchedCandidate &Preferred)
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)
LLVM_ABI 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.
MachineSchedPolicy getPolicy () const override
void traceCandidate (const SchedCandidate &Cand)

Protected Attributes

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
GCNDownwardRPTracker DownwardTracker
GCNUpwardRPTracker UpwardTracker
Protected Attributes inherited from llvm::GenericScheduler
ScheduleDAGMILive * DAG = nullptr
SchedBoundary Top
SchedBoundary Bot
unsigned TopClusterID
unsigned BotClusterID
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
unsigned TopIdx = 0
unsigned BotIdx = 0
unsigned NumRegionInstrs = 0
MachineSchedPolicy RegionPolicy
SchedRemainder Rem

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 , NodeOrder ,
  FirstValid
}
 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)

Detailed Description

This is a minimal scheduler strategy.

The main difference between this and the GenericScheduler is that GCNSchedStrategy uses different heuristics to determine excess/critical pressure sets.

Definition at line 45 of file GCNSchedStrategy.h.

Constructor & Destructor Documentation

◆ GCNSchedStrategy()

GCNSchedStrategy::GCNSchedStrategy ( const MachineSchedContext * C)

Definition at line 95 of file GCNSchedStrategy.cpp.

References llvm::CallingConv::C, DownwardTracker, llvm::GenericScheduler::GenericScheduler(), HasHighPressure, MF, TargetOccupancy, and UpwardTracker.

Referenced by llvm::GCNMaxILPSchedStrategy::GCNMaxILPSchedStrategy(), llvm::GCNMaxMemoryClauseSchedStrategy::GCNMaxMemoryClauseSchedStrategy(), and llvm::GCNMaxOccupancySchedStrategy::GCNMaxOccupancySchedStrategy().

Member Function Documentation

◆ advanceStage()

bool GCNSchedStrategy::advanceStage ( )

Definition at line 628 of file GCNSchedStrategy.cpp.

References assert(), CurrentStage, and SchedStages.

◆ getCurrentStage()

GCNSchedStageID GCNSchedStrategy::getCurrentStage ( )

Definition at line 623 of file GCNSchedStrategy.cpp.

References assert(), CurrentStage, and SchedStages.

◆ getDownwardTracker()

GCNDownwardRPTracker * llvm::GCNSchedStrategy::getDownwardTracker ( )
inline

Definition at line 146 of file GCNSchedStrategy.h.

References DownwardTracker.

◆ getNextStage()

GCNSchedStageID GCNSchedStrategy::getNextStage ( ) const

Definition at line 643 of file GCNSchedStrategy.cpp.

References assert(), CurrentStage, and SchedStages.

◆ getTargetOccupancy()

unsigned llvm::GCNSchedStrategy::getTargetOccupancy ( )
inline

Definition at line 133 of file GCNSchedStrategy.h.

References TargetOccupancy.

◆ getUpwardTracker()

GCNUpwardRPTracker * llvm::GCNSchedStrategy::getUpwardTracker ( )
inline

Definition at line 148 of file GCNSchedStrategy.h.

References UpwardTracker.

◆ hasNextStage()

bool GCNSchedStrategy::hasNextStage ( ) const

Definition at line 638 of file GCNSchedStrategy.cpp.

References assert(), CurrentStage, and SchedStages.

◆ initCandidate()

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

Definition at line 221 of file GCNSchedStrategy.cpp.

References llvm::GenericSchedulerBase::SchedCandidate::AtTop, canUsePressureDiffs(), llvm::RegPressureDelta::CriticalMax, llvm::GenericScheduler::DAG, DownwardTracker, llvm::errs(), llvm::RegPressureDelta::Excess, GCNTrackers, getRegisterPressures(), HasHighPressure, MaxPressure, Pressure, llvm::report_fatal_error(), llvm::GenericSchedulerBase::SchedCandidate::RPDelta, llvm::PressureChange::setUnitInc(), SGPRCriticalLimit, SGPRExcessLimit, llvm::GenericSchedulerBase::SchedCandidate::SU, UpwardTracker, VGPRCriticalLimit, and VGPRExcessLimit.

Referenced by pickNodeFromQueue().

◆ initialize()

void GCNSchedStrategy::initialize ( ScheduleDAGMI * DAG)
overridevirtual

Initialize the strategy after building the DAG for a new region.

Implements llvm::MachineSchedStrategy.

Definition at line 100 of file GCNSchedStrategy.cpp.

References llvm::alignDown(), llvm::GenericSchedulerBase::Context, llvm::GenericScheduler::DAG, llvm::dbgs(), ErrorMargin, llvm::AMDGPU::IsaInfo::getAddressableNumVGPRs(), llvm::SIMachineFunctionInfo::getDynamicVGPRBlockSize(), llvm::SIMachineFunctionInfo::getMinAllowedOccupancy(), llvm::SIMachineFunctionInfo::getOccupancy(), llvm::AMDGPU::IsaInfo::getVGPRAllocGranule(), llvm::GenericScheduler::initialize(), KnownExcessRP, LLVM_DEBUG, MF, RelaxedOcc, SGPRCriticalLimit, SGPRExcessLimit, SGPRLimitBias, TargetOccupancy, VGPRCriticalLimit, VGPRExcessLimit, and VGPRLimitBias.

◆ pickNode()

SUnit * GCNSchedStrategy::pickNode ( bool & IsTopNode)
overridevirtual

Pick the next node to schedule, or return NULL.

Set IsTopNode to true to schedule the node at the top of the unscheduled region. Otherwise it will be scheduled at the bottom.

Implements llvm::MachineSchedStrategy.

Definition at line 548 of file GCNSchedStrategy.cpp.

References assert(), llvm::GenericScheduler::Bot, llvm::GenericScheduler::BotCand, llvm::SUnit::BotReadyCycle, llvm::SchedBoundary::bumpCycle(), llvm::SchedBoundary::checkHazard(), llvm::GenericScheduler::DAG, llvm::dbgs(), llvm::SchedBoundary::getCurrCycle(), llvm::SUnit::getInstr(), llvm::SUnit::isBottomReady(), llvm::SUnit::isScheduled, llvm::SUnit::isTopReady(), LLVM_DEBUG, llvm::GenericSchedulerBase::NoCand, llvm::SUnit::NodeNum, pickNodeBidirectional(), pickNodeFromQueue(), pickOnlyChoice(), llvm::GenericSchedulerBase::RegionPolicy, llvm::SchedBoundary::releasePending(), llvm::GenericSchedulerBase::SchedModel, llvm::GenericScheduler::Top, llvm::GenericScheduler::TopCand, and llvm::SUnit::TopReadyCycle.

◆ pickNodeBidirectional()

SUnit * GCNSchedStrategy::pickNodeBidirectional ( bool & IsTopNode,
bool & PickedPending )
protected

Definition at line 451 of file GCNSchedStrategy.cpp.

References assert(), llvm::GenericScheduler::Bot, llvm::GenericScheduler::BotCand, llvm::GenericScheduler::DAG, llvm::dbgs(), LLVM_DEBUG, llvm::GenericSchedulerBase::NoCand, pickNodeFromQueue(), pickOnlyChoice(), llvm::GenericSchedulerBase::SchedCandidate::Reason, llvm::GenericSchedulerBase::SchedCandidate::reset(), llvm::GenericSchedulerBase::SchedModel, llvm::GenericSchedulerBase::setPolicy(), llvm::GenericSchedulerBase::SchedCandidate::SU, llvm::GenericScheduler::Top, llvm::GenericScheduler::TopCand, llvm::GenericSchedulerBase::traceCandidate(), llvm::GenericScheduler::tryCandidate(), tryPendingCandidate(), and llvm::VerifyScheduling.

Referenced by pickNode().

◆ pickNodeFromQueue()

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

Definition at line 380 of file GCNSchedStrategy.cpp.

References llvm::GenericSchedulerBase::SchedCandidate::AtTop, llvm::SchedBoundary::Available, llvm::GenericScheduler::DAG, llvm::SchedBoundary::DAG, llvm::dbgs(), DownwardTracker, GCNTrackers, llvm::RegPressureTracker::getRegSetPressureAtPos(), initCandidate(), llvm::GenericSchedulerBase::SchedCandidate::initResourceDelta(), llvm::SchedBoundary::isTop(), LLVM_DEBUG, llvm::GenericSchedulerBase::NoCand, llvm::SchedBoundary::Pending, Pressure, printCandidateDecision(), llvm::GenericSchedulerBase::SchedCandidate::Reason, llvm::GenericSchedulerBase::SchedCandidate::ResDelta, llvm::GenericSchedulerBase::SchedModel, llvm::GenericSchedulerBase::SchedCandidate::setBest(), shouldCheckPending(), T, llvm::GenericSchedulerBase::TRI, llvm::GenericScheduler::tryCandidate(), tryPendingCandidate(), and UpwardTracker.

Referenced by pickNode(), and pickNodeBidirectional().

◆ printCandidateDecision()

void GCNSchedStrategy::printCandidateDecision ( const SchedCandidate & Current,
const SchedCandidate & Preferred )
protected

Definition at line 362 of file GCNSchedStrategy.cpp.

References llvm::GenericScheduler::DAG, llvm::dbgs(), LLVM_DEBUG, llvm::GenericSchedulerBase::SchedCandidate::SU, and llvm::GenericSchedulerBase::traceCandidate().

Referenced by pickNodeFromQueue().

◆ schedNode()

void GCNSchedStrategy::schedNode ( SUnit * SU,
bool IsTopNode )
overridevirtual

Notify MachineSchedStrategy that ScheduleDAGMI has scheduled an instruction and updated scheduled/remaining flags in the DAG nodes.

Implements llvm::MachineSchedStrategy.

Definition at line 613 of file GCNSchedStrategy.cpp.

References DownwardTracker, GCNTrackers, llvm::SUnit::getInstr(), MI, llvm::GenericScheduler::schedNode(), and UpwardTracker.

◆ setTargetOccupancy()

void llvm::GCNSchedStrategy::setTargetOccupancy ( unsigned Occ)
inline

Definition at line 135 of file GCNSchedStrategy.h.

References TargetOccupancy.

Referenced by llvm::GCNIterativeScheduler::scheduleLegacyMaxOccupancy().

◆ tryPendingCandidate()

bool GCNSchedStrategy::tryPendingCandidate ( SchedCandidate & Cand,
SchedCandidate & TryCand,
SchedBoundary * Zone ) const
protected

Evaluates instructions in the pending queue using a subset of scheduling heuristics.

Instructions that cannot be issued due to hardware constraints are placed in the pending queue rather than the available queue, making them normally invisible to scheduling heuristics. However, in certain scenarios (such as avoiding register spilling), it may be beneficial to consider scheduling these not-yet-ready instructions.

Definition at line 648 of file GCNSchedStrategy.cpp.

References llvm::GenericSchedulerBase::SchedCandidate::AtTop, llvm::biasPhysReg(), llvm::RegPressureDelta::CriticalMax, llvm::GenericSchedulerBase::SchedResourceDelta::CritResources, llvm::GenericScheduler::DAG, llvm::GenericSchedulerBase::SchedResourceDelta::DemandedResources, llvm::RegPressureDelta::Excess, llvm::GenericSchedulerBase::SchedCandidate::initResourceDelta(), llvm::GenericSchedulerBase::SchedCandidate::isValid(), llvm::GenericSchedulerBase::NoCand, llvm::GenericSchedulerBase::NodeOrder, llvm::GenericSchedulerBase::PhysReg, llvm::GenericSchedulerBase::SchedCandidate::Reason, llvm::GenericSchedulerBase::RegCritical, llvm::GenericSchedulerBase::RegExcess, llvm::GenericSchedulerBase::SchedCandidate::ResDelta, llvm::GenericSchedulerBase::ResourceDemand, llvm::GenericSchedulerBase::ResourceReduce, llvm::GenericSchedulerBase::SchedCandidate::RPDelta, llvm::GenericSchedulerBase::SchedModel, llvm::GenericSchedulerBase::SchedCandidate::SU, llvm::GenericSchedulerBase::TRI, llvm::tryGreater(), llvm::tryLess(), and llvm::tryPressure().

Referenced by pickNodeBidirectional(), and pickNodeFromQueue().

Member Data Documentation

◆ CurrentStage

SmallVectorImpl<GCNSchedStageID>::iterator llvm::GCNSchedStrategy::CurrentStage = nullptr
protected

Definition at line 89 of file GCNSchedStrategy.h.

Referenced by advanceStage(), getCurrentStage(), getNextStage(), and hasNextStage().

◆ DownwardTracker

GCNDownwardRPTracker llvm::GCNSchedStrategy::DownwardTracker
mutableprotected

Definition at line 92 of file GCNSchedStrategy.h.

Referenced by GCNSchedStrategy(), getDownwardTracker(), initCandidate(), pickNodeFromQueue(), and schedNode().

◆ ErrorMargin

unsigned llvm::GCNSchedStrategy::ErrorMargin = 3

Definition at line 109 of file GCNSchedStrategy.h.

Referenced by initialize().

◆ HasHighPressure

bool llvm::GCNSchedStrategy::HasHighPressure

Definition at line 100 of file GCNSchedStrategy.h.

Referenced by GCNSchedStrategy(), and initCandidate().

◆ HighRPSGPRBias

const unsigned llvm::GCNSchedStrategy::HighRPSGPRBias = 7

Definition at line 112 of file GCNSchedStrategy.h.

◆ HighRPVGPRBias

const unsigned llvm::GCNSchedStrategy::HighRPVGPRBias = 7

Definition at line 115 of file GCNSchedStrategy.h.

◆ KnownExcessRP

bool llvm::GCNSchedStrategy::KnownExcessRP = false

Definition at line 104 of file GCNSchedStrategy.h.

Referenced by initialize().

◆ MaxPressure

std::vector<unsigned> llvm::GCNSchedStrategy::MaxPressure
protected

Definition at line 75 of file GCNSchedStrategy.h.

Referenced by initCandidate().

◆ MF

MachineFunction* llvm::GCNSchedStrategy::MF
protected

Definition at line 83 of file GCNSchedStrategy.h.

Referenced by GCNSchedStrategy(), and initialize().

◆ Pressure

std::vector<unsigned> llvm::GCNSchedStrategy::Pressure
protected

Definition at line 73 of file GCNSchedStrategy.h.

Referenced by initCandidate(), and pickNodeFromQueue().

◆ SchedStages

SmallVector<GCNSchedStageID, 4> llvm::GCNSchedStrategy::SchedStages
protected

Definition at line 86 of file GCNSchedStrategy.h.

Referenced by advanceStage(), llvm::GCNMaxILPSchedStrategy::GCNMaxILPSchedStrategy(), llvm::GCNMaxMemoryClauseSchedStrategy::GCNMaxMemoryClauseSchedStrategy(), llvm::GCNMaxOccupancySchedStrategy::GCNMaxOccupancySchedStrategy(), getCurrentStage(), getNextStage(), and hasNextStage().

◆ SGPRCriticalLimit

unsigned llvm::GCNSchedStrategy::SGPRCriticalLimit

Definition at line 117 of file GCNSchedStrategy.h.

Referenced by initCandidate(), and initialize().

◆ SGPRExcessLimit

unsigned llvm::GCNSchedStrategy::SGPRExcessLimit
protected

Definition at line 77 of file GCNSchedStrategy.h.

Referenced by initCandidate(), and initialize().

◆ SGPRLimitBias

unsigned llvm::GCNSchedStrategy::SGPRLimitBias = 0

Definition at line 121 of file GCNSchedStrategy.h.

Referenced by initialize().

◆ TargetOccupancy

unsigned llvm::GCNSchedStrategy::TargetOccupancy
protected

Definition at line 81 of file GCNSchedStrategy.h.

Referenced by GCNSchedStrategy(), getTargetOccupancy(), initialize(), and setTargetOccupancy().

◆ UpwardTracker

GCNUpwardRPTracker llvm::GCNSchedStrategy::UpwardTracker
mutableprotected

Definition at line 95 of file GCNSchedStrategy.h.

Referenced by GCNSchedStrategy(), getUpwardTracker(), initCandidate(), pickNodeFromQueue(), and schedNode().

◆ VGPRCriticalLimit

unsigned llvm::GCNSchedStrategy::VGPRCriticalLimit

Definition at line 119 of file GCNSchedStrategy.h.

Referenced by initCandidate(), and initialize().

◆ VGPRExcessLimit

unsigned llvm::GCNSchedStrategy::VGPRExcessLimit
protected

Definition at line 79 of file GCNSchedStrategy.h.

Referenced by initCandidate(), and initialize().

◆ VGPRLimitBias

unsigned llvm::GCNSchedStrategy::VGPRLimitBias = 0

Definition at line 123 of file GCNSchedStrategy.h.

Referenced by initialize().

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