LLVM 22.0.0git
Public Member Functions | Protected Member Functions | List of all members
llvm::GCNMaxILPSchedStrategy Class Referencefinal

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 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.

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)
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)

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)
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
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

Detailed Description

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

latency hiding).

Definition at line 146 of file GCNSchedStrategy.h.

Constructor & Destructor Documentation

◆ GCNMaxILPSchedStrategy()

GCNMaxILPSchedStrategy::GCNMaxILPSchedStrategy ( const MachineSchedContext * C)

Definition at line 537 of file GCNSchedStrategy.cpp.

References llvm::CallingConv::C, llvm::GCNSchedStrategy::GCNSchedStrategy(), llvm::ILPInitialSchedule, 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
Candprovides the policy and current best candidate.
TryCandrefers to the next SUnit candidate, otherwise uninitialized.
Zonedescribes 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 542 of file GCNSchedStrategy.cpp.

References llvm::GenericSchedulerBase::SchedCandidate::AtTop, llvm::biasPhysReg(), llvm::GenericScheduler::BotClusterID, llvm::GenericSchedulerBase::Cluster, llvm::RegPressureDelta::CriticalMax, llvm::GenericSchedulerBase::SchedResourceDelta::CritResources, llvm::RegPressureDelta::CurrentMax, llvm::GenericScheduler::DAG, llvm::GenericSchedulerBase::SchedResourceDelta::DemandedResources, llvm::RegPressureDelta::Excess, llvm::SchedBoundary::getLatencyStallCycles(), llvm::getWeakLeft(), llvm::GenericSchedulerBase::SchedCandidate::initResourceDelta(), llvm::isTheSameCluster(), llvm::SchedBoundary::isTop(), llvm::GenericSchedulerBase::SchedCandidate::isValid(), llvm::NoCand, llvm::SUnit::NodeNum, llvm::NodeOrder, llvm::SUnit::ParentClusterIdx, llvm::GenericSchedulerBase::PhysReg, llvm::GenericSchedulerBase::SchedCandidate::Reason, llvm::GenericSchedulerBase::RegCritical, llvm::GenericSchedulerBase::RegExcess, llvm::GenericSchedulerBase::RegMax, llvm::GenericSchedulerBase::SchedCandidate::ResDelta, llvm::GenericSchedulerBase::ResourceDemand, llvm::GenericSchedulerBase::ResourceReduce, llvm::GenericSchedulerBase::SchedCandidate::RPDelta, llvm::GenericSchedulerBase::SchedModel, llvm::GenericSchedulerBase::Stall, llvm::GenericSchedulerBase::SchedCandidate::SU, llvm::GenericScheduler::TopClusterID, llvm::GenericSchedulerBase::TRI, llvm::tryGreater(), llvm::tryLatency(), llvm::tryLess(), llvm::tryPressure(), and llvm::GenericSchedulerBase::Weak.

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