LLVM  16.0.0git
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:
Inheritance graph
Collaboration diagram for llvm::GCNMaxILPSchedStrategy:
Collaboration graph

Public Member Functions

 GCNMaxILPSchedStrategy (const MachineSchedContext *C)
- Public Member Functions inherited from llvm::GCNSchedStrategy
 GCNSchedStrategy (const MachineSchedContext *C)
SUnitpickNode (bool &IsTopNode) override
 Pick the best node to balance the schedule. Implements MachineSchedStrategy. More...
void initialize (ScheduleDAGMI *DAG) override
 Initialize the strategy after building the DAG for a new region. More...
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. More...
void dumpPolicy () const override
bool shouldTrackPressure () const override
 Check if pressure tracking is needed before building the DAG and initializing this strategy. More...
bool shouldTrackLaneMasks () const override
 Returns true if lanemasks should be tracked. More...
void schedNode (SUnit *SU, bool IsTopNode) override
 Update the scheduler's state after scheduling a node. More...
void releaseTopNode (SUnit *SU) override
 When all predecessor dependencies have been resolved, free this node for top-down scheduling. More...
void releaseBottomNode (SUnit *SU) override
 When all successor dependencies have been resolved, free this node for bottom-up scheduling. More...
void registerRoots () override
 Notify this strategy that all roots have been released (including those that depend on EntrySU or ExitSU). More...
- 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. More...
virtual void leaveMBB ()
 Tell the strategy that current MBB is done. More...
virtual void scheduleTree (unsigned SubtreeID)
 Scheduler callback to notify that a new subtree is scheduled. More...

Protected Member Functions

bool tryCandidate (SchedCandidate &Cand, SchedCandidate &TryCand, SchedBoundary *Zone) const override
 Apply a set of heuristics to a new candidate. More...
- Protected Member Functions inherited from llvm::GCNSchedStrategy
SUnitpickNodeBidirectional (bool &IsTopNode)
void pickNodeFromQueue (SchedBoundary &Zone, const CandPolicy &ZonePolicy, const RegPressureTracker &RPTracker, SchedCandidate &Cand)
void initCandidate (SchedCandidate &Cand, SUnit *SU, bool AtTop, const RegPressureTracker &RPTracker, const SIRegisterInfo *SRI, unsigned SGPRPressure, unsigned VGPRPressure)
- 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. More...
void initCandidate (SchedCandidate &Cand, SUnit *SU, bool AtTop, const RegPressureTracker &RPTracker, RegPressureTracker &TempTracker)
SUnitpickNodeBidirectional (bool &IsTopNode)
 Pick the best candidate node from either the top or bottom queue. More...
void pickNodeFromQueue (SchedBoundary &Zone, const CandPolicy &ZonePolicy, const RegPressureTracker &RPTracker, SchedCandidate &Candidate)
 Pick the best candidate from the queue. More...
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. More...
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,
 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
const unsigned DefaultErrorMargin = 3
const unsigned HighRPErrorMargin = 10
unsigned ErrorMargin = DefaultErrorMargin
unsigned SGPRCriticalLimit
unsigned VGPRCriticalLimit
- Protected Attributes inherited from llvm::GCNSchedStrategy
std::vector< unsigned > Pressure
std::vector< unsigned > MaxPressure
unsigned SGPRExcessLimit
unsigned VGPRExcessLimit
unsigned TargetOccupancy
SmallVector< GCNSchedStageID, 4 > SchedStages
SmallVectorImpl< GCNSchedStageID >::iterator CurrentStage = nullptr
- Protected Attributes inherited from llvm::GenericScheduler
ScheduleDAGMILiveDAG = nullptr
MachineSchedPolicy RegionPolicy
SchedBoundary Top
SchedBoundary Bot
SchedCandidate TopCand
 Candidate last picked from Top boundary. More...
SchedCandidate BotCand
 Candidate last picked from Bot boundary. More...
- Protected Attributes inherited from llvm::GenericSchedulerBase
const MachineSchedContextContext
const TargetSchedModelSchedModel = nullptr
const TargetRegisterInfoTRI = 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 120 of file GCNSchedStrategy.h.

Constructor & Destructor Documentation

◆ GCNMaxILPSchedStrategy()

GCNMaxILPSchedStrategy::GCNMaxILPSchedStrategy ( const MachineSchedContext C)

Member Function Documentation

◆ tryCandidate()

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

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.

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

Reimplemented from llvm::GenericScheduler.

Definition at line 357 of file GCNSchedStrategy.cpp.

References llvm::GenericSchedulerBase::SchedCandidate::AtTop, llvm::biasPhysReg(), 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::ScheduleDAGMI::getNextClusterPred(), llvm::ScheduleDAGMI::getNextClusterSucc(), llvm::getWeakLeft(), llvm::GenericSchedulerBase::SchedCandidate::initResourceDelta(), llvm::SchedBoundary::isTop(), llvm::ScheduleDAGMILive::isTrackingPressure(), llvm::GenericSchedulerBase::SchedCandidate::isValid(), llvm::ScheduleDAG::MF, llvm::GenericSchedulerBase::NoCand, llvm::SUnit::NodeNum, llvm::GenericSchedulerBase::NodeOrder, 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::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: