Each Scheduling boundary is associated with ready queues. More...

#include "llvm/CodeGen/MachineScheduler.h"

Collaboration diagram for llvm::SchedBoundary:

[legend]

Public Types
enum	{ TopQID = 1, BotQID = 2, LogMaxQID = 2 }
	SUnit::NodeQueueId: 0 (none), 1 (top), 2 (bot), 3 (both) More...

Public Member Functions
	SchedBoundary (unsigned ID, const Twine &Name)
	Pending queues extend the ready queues with the same ID and the PendingFlag set. More...

	~SchedBoundary ()

void	reset ()

void	init (ScheduleDAGMI dag, const TargetSchedModel smodel, SchedRemainder *rem)

bool	isTop () const

unsigned	getCurrCycle () const
	Number of cycles to issue the instructions scheduled in this zone. More...

unsigned	getCurrMOps () const
	Micro-ops issued in the current cycle. More...

unsigned	getDependentLatency () const

unsigned	getScheduledLatency () const
	Get the number of latency cycles "covered" by the scheduled instructions. More...

unsigned	getUnscheduledLatency (SUnit *SU) const

unsigned	getResourceCount (unsigned ResIdx) const

unsigned	getCriticalCount () const
	Get the scaled count of scheduled micro-ops and resources, including executed resources. More...

unsigned	getExecutedCount () const
	Get a scaled count for the minimum execution time of the scheduled micro-ops that are ready to execute by getExecutedCount. More...

unsigned	getZoneCritResIdx () const

bool	isResourceLimited () const

unsigned	getLatencyStallCycles (SUnit *SU)
	Get the difference between the given SUnit's ready time and the current cycle. More...

unsigned	getNextResourceCycle (unsigned PIdx, unsigned Cycles)
	Compute the next cycle at which the given processor resource can be scheduled. More...

bool	checkHazard (SUnit *SU)
	Does this SU have a hazard within the current instruction group. More...

unsigned	findMaxLatency (ArrayRef< SUnit *> ReadySUs)

unsigned	getOtherResourceCount (unsigned &OtherCritIdx)

void	releaseNode (SUnit *SU, unsigned ReadyCycle)

void	bumpCycle (unsigned NextCycle)
	Move the boundary of scheduled code by one cycle. More...

void	incExecutedResources (unsigned PIdx, unsigned Count)

unsigned	countResource (unsigned PIdx, unsigned Cycles, unsigned ReadyCycle)
	Add the given processor resource to this scheduled zone. More...

void	bumpNode (SUnit *SU)
	Move the boundary of scheduled code by one SUnit. More...

void	releasePending ()
	Release pending ready nodes in to the available queue. More...

void	removeReady (SUnit *SU)
	Remove SU from the ready set for this boundary. More...

SUnit *	pickOnlyChoice ()
	Call this before applying any other heuristics to the Available queue. More...

void	dumpScheduledState () const

Public Attributes
ScheduleDAGMI *	DAG = nullptr

const TargetSchedModel *	SchedModel = nullptr

SchedRemainder *	Rem = nullptr

ReadyQueue	Available

ReadyQueue	Pending

ScheduleHazardRecognizer *	HazardRec = nullptr

Detailed Description

Each Scheduling boundary is associated with ready queues.

It tracks the current cycle in the direction of movement, and maintains the state of "hazards" and other interlocks at the current cycle.

Definition at line 619 of file MachineScheduler.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

SUnit::NodeQueueId: 0 (none), 1 (top), 2 (bot), 3 (both)

Enumerator
TopQID
BotQID
LogMaxQID

Definition at line 622 of file MachineScheduler.h.

Constructor & Destructor Documentation

◆ SchedBoundary()

llvm::SchedBoundary::SchedBoundary	(	unsigned	ID,
		const Twine &	Name
	)

inline

Pending queues extend the ready queues with the same ID and the PendingFlag set.

Definition at line 694 of file MachineScheduler.h.

References llvm::cl::init().

◆ ~SchedBoundary()

SchedBoundary::~SchedBoundary ( )

Definition at line 1856 of file MachineScheduler.cpp.

Member Function Documentation

◆ bumpCycle()

void SchedBoundary::bumpCycle ( unsigned NextCycle )

Move the boundary of scheduled code by one cycle.

Definition at line 2090 of file MachineScheduler.cpp.

References assert(), checkResourceLimit(), llvm::dbgs(), LLVM_DEBUG, and llvm::max().

◆ bumpNode()

void SchedBoundary::bumpNode ( SUnit * SU )

Move the boundary of scheduled code by one SUnit.

Definition at line 2173 of file MachineScheduler.cpp.

References assert(), llvm::SUnit::BotReadyCycle, checkResourceLimit(), llvm::dbgs(), llvm::SUnit::getDepth(), llvm::SUnit::getHeight(), llvm::SUnit::getInstr(), llvm::ScheduleDAGInstrs::getSchedClass(), llvm::SUnit::hasReservedResource, llvm::SUnit::isCall, llvm::SUnit::isUnbuffered, LLVM_DEBUG, llvm::max(), llvm::SUnit::NodeNum, llvm::PPCISD::SC, and llvm::SUnit::TopReadyCycle.

◆ checkHazard()

bool SchedBoundary::checkHazard ( SUnit * SU )

Does this SU have a hazard within the current instruction group.

The scheduler supports two modes of hazard recognition. The first is the ScheduleHazardRecognizer API. It is a fully general hazard recognizer that supports highly complicated in-order reservation tables (ScoreboardHazardRecognizer) and arbitrary target-specific logic.

The second is a streamlined mechanism that checks for hazards based on simple counters that the scheduler itself maintains. It explicitly checks for instruction dispatch limitations, including the number of micro-ops that can dispatch per cycle.

TODO: Also check whether the SU must start a new group.

Definition at line 1973 of file MachineScheduler.cpp.

References llvm::dbgs(), findMaxLatency(), llvm::SUnit::getInstr(), llvm::ScheduleDAGInstrs::getSchedClass(), llvm::SUnit::hasReservedResource, LLVM_DEBUG, llvm::make_range(), llvm::max(), llvm::SUnit::NodeNum, llvm::ScheduleHazardRecognizer::NoHazard, and llvm::PPCISD::SC.

◆ countResource()

unsigned SchedBoundary::countResource	(	unsigned	PIdx,
		unsigned	Cycles,
		unsigned	NextCycle
	)

Add the given processor resource to this scheduled zone.

Parameters

Cycles indicates the number of consecutive (non-pipelined) cycles during which this resource is consumed.

Returns: the next cycle at which the instruction may execute without oversubscribing resources.

Definition at line 2142 of file MachineScheduler.cpp.

References assert(), llvm::dbgs(), and LLVM_DEBUG.

Referenced by incExecutedResources().

◆ dumpScheduledState()

LLVM_DUMP_METHOD void SchedBoundary::dumpScheduledState ( ) const

Definition at line 2393 of file MachineScheduler.cpp.

References llvm::dbgs(), and llvm::GenericSchedulerBase::SchedCandidate::initResourceDelta().

◆ findMaxLatency()

unsigned SchedBoundary::findMaxLatency ( ArrayRef< SUnit *> ReadySUs )

Definition at line 2018 of file MachineScheduler.cpp.

References llvm::dbgs(), getOtherResourceCount(), LLVM_DEBUG, and llvm::SUnit::NodeNum.

Referenced by checkHazard(), and computeRemLatency().

◆ getCriticalCount()

unsigned llvm::SchedBoundary::getCriticalCount ( ) const

inline

Get the scaled count of scheduled micro-ops and resources, including executed resources.

Definition at line 736 of file MachineScheduler.h.

References llvm::TargetSchedModel::getMicroOpFactor().

◆ getCurrCycle()

unsigned llvm::SchedBoundary::getCurrCycle ( ) const

inline

Number of cycles to issue the instructions scheduled in this zone.

Definition at line 711 of file MachineScheduler.h.

Referenced by computeRemLatency(), and llvm::GenericSchedulerBase::setPolicy().

◆ getCurrMOps()

unsigned llvm::SchedBoundary::getCurrMOps ( ) const

inline

Micro-ops issued in the current cycle.

Definition at line 714 of file MachineScheduler.h.

Referenced by llvm::GenericScheduler::tryCandidate().

◆ getDependentLatency()

unsigned llvm::SchedBoundary::getDependentLatency ( ) const

inline

Definition at line 717 of file MachineScheduler.h.

Referenced by computeRemLatency().

◆ getExecutedCount()

unsigned llvm::SchedBoundary::getExecutedCount ( ) const

inline

Get a scaled count for the minimum execution time of the scheduled micro-ops that are ready to execute by getExecutedCount.

Notice the feedback loop.

Definition at line 745 of file MachineScheduler.h.

References llvm::TargetSchedModel::getLatencyFactor(), and llvm::max().

◆ getLatencyStallCycles()

unsigned SchedBoundary::getLatencyStallCycles ( SUnit * SU )

Get the difference between the given SUnit's ready time and the current cycle.

Compute the stall cycles based on this SUnit's ready time.

Heuristics treat these "soft stalls" differently than the hard stall cycles based on CPU resources and computed by checkHazard(). A fully in-order model (MicroOpBufferSize==0) will not make use of this since instructions are not available for scheduling until they are ready. However, a weaker in-order model may use this for heuristics. For example, if a processor has in-order behavior when reading certain resources, this may come into play.

Definition at line 1936 of file MachineScheduler.cpp.

References llvm::SUnit::BotReadyCycle, getNextResourceCycle(), llvm::SUnit::isUnbuffered, and llvm::SUnit::TopReadyCycle.

Referenced by llvm::GenericScheduler::tryCandidate().

◆ getNextResourceCycle()

unsigned SchedBoundary::getNextResourceCycle	(	unsigned	PIdx,
		unsigned	Cycles
	)

Compute the next cycle at which the given processor resource can be scheduled.

Definition at line 1949 of file MachineScheduler.cpp.

Referenced by getLatencyStallCycles().

◆ getOtherResourceCount()

unsigned SchedBoundary::getOtherResourceCount ( unsigned & OtherCritIdx )

Definition at line 2039 of file MachineScheduler.cpp.

References llvm::dbgs(), and LLVM_DEBUG.

Referenced by findMaxLatency(), and llvm::GenericSchedulerBase::setPolicy().

◆ getResourceCount()

unsigned llvm::SchedBoundary::getResourceCount ( unsigned ResIdx ) const

inline

Definition at line 730 of file MachineScheduler.h.

◆ getScheduledLatency()

unsigned llvm::SchedBoundary::getScheduledLatency ( ) const

inline

Get the number of latency cycles "covered" by the scheduled instructions.

This is the larger of the critical path within the zone and the number of cycles required to issue the instructions.

Definition at line 722 of file MachineScheduler.h.

References llvm::max().

Referenced by llvm::tryLatency().

◆ getUnscheduledLatency()

unsigned llvm::SchedBoundary::getUnscheduledLatency ( SUnit * SU ) const

inline

Definition at line 726 of file MachineScheduler.h.

References llvm::SUnit::getDepth(), and llvm::SUnit::getHeight().

◆ getZoneCritResIdx()

unsigned llvm::SchedBoundary::getZoneCritResIdx ( ) const

inline

Definition at line 750 of file MachineScheduler.h.

Referenced by llvm::GenericSchedulerBase::setPolicy().

◆ incExecutedResources()

void SchedBoundary::incExecutedResources	(	unsigned	PIdx,
		unsigned	Count
	)

Definition at line 2128 of file MachineScheduler.cpp.

References countResource().

◆ init()

void SchedBoundary::init	(	ScheduleDAGMI *	dag,
		const TargetSchedModel *	smodel,
		SchedRemainder *	rem
	)

Definition at line 1918 of file MachineScheduler.cpp.

References InvalidCycle.

Referenced by llvm::SchedRemainder::init().

◆ isResourceLimited()

bool llvm::SchedBoundary::isResourceLimited ( ) const

inline

Definition at line 753 of file MachineScheduler.h.

Referenced by llvm::GenericSchedulerBase::setPolicy().

◆ isTop()

bool llvm::SchedBoundary::isTop ( ) const

inline

Definition at line 706 of file MachineScheduler.h.

References llvm::ReadyQueue::getID().

Referenced by llvm::GCNMaxOccupancySchedStrategy::initialize(), llvm::GenericScheduler::pickNodeFromQueue(), llvm::GenericScheduler::tryCandidate(), and llvm::tryLatency().

◆ pickOnlyChoice()

SUnit * SchedBoundary::pickOnlyChoice ( )

Call this before applying any other heuristics to the Available queue.

If this queue only has one ready candidate, return it.

Updates the Available/Pending Q's if necessary and returns the single available instruction, or NULL if there are multiple candidates.

As a side effect, defer any nodes that now hit a hazard, and advance the cycle until at least one node is ready. If multiple instructions are ready, return NULL.

Definition at line 2358 of file MachineScheduler.cpp.

References I, and LLVM_DEBUG.

Referenced by llvm::GCNMaxOccupancySchedStrategy::initialize(), and llvm::GCNMaxOccupancySchedStrategy::pickNode().

◆ releaseNode()

void SchedBoundary::releaseNode	(	SUnit *	SU,
		unsigned	ReadyCycle
	)

Definition at line 2065 of file MachineScheduler.cpp.

References assert(), llvm::SUnit::getInstr(), llvm::max(), and ReadyListLimit.

Referenced by llvm::PostGenericScheduler::releaseTopNode().

◆ releasePending()

void SchedBoundary::releasePending ( )

Release pending ready nodes in to the available queue.

This makes them visible to heuristics.

Definition at line 2314 of file MachineScheduler.cpp.

References llvm::SUnit::BotReadyCycle, llvm::max(), ReadyListLimit, and llvm::SUnit::TopReadyCycle.

◆ removeReady()

void SchedBoundary::removeReady ( SUnit * SU )

Remove SU from the ready set for this boundary.

Definition at line 2346 of file MachineScheduler.cpp.

References assert().

Referenced by llvm::GCNMaxOccupancySchedStrategy::pickNode().

◆ reset()

void SchedBoundary::reset ( )

Definition at line 1865 of file MachineScheduler.cpp.

References assert(), llvm::SchedRemainder::init(), and llvm::max().

Member Data Documentation

◆ Available

ReadyQueue llvm::SchedBoundary::Available

Definition at line 632 of file MachineScheduler.h.

Referenced by computeRemLatency(), llvm::GCNMaxOccupancySchedStrategy::initialize(), llvm::GCNMaxOccupancySchedStrategy::pickNode(), llvm::GenericScheduler::pickNodeFromQueue(), and llvm::GenericSchedulerBase::setPolicy().

◆ DAG

ScheduleDAGMI* llvm::SchedBoundary::DAG = nullptr

Definition at line 628 of file MachineScheduler.h.

Referenced by llvm::GCNMaxOccupancySchedStrategy::initialize().

◆ HazardRec

ScheduleHazardRecognizer* llvm::SchedBoundary::HazardRec = nullptr

Definition at line 635 of file MachineScheduler.h.

◆ Pending

ReadyQueue llvm::SchedBoundary::Pending

Definition at line 633 of file MachineScheduler.h.

Referenced by computeRemLatency(), and llvm::GCNMaxOccupancySchedStrategy::pickNode().

◆ Rem

SchedRemainder* llvm::SchedBoundary::Rem = nullptr

Definition at line 630 of file MachineScheduler.h.

◆ SchedModel

const TargetSchedModel* llvm::SchedBoundary::SchedModel = nullptr

Definition at line 629 of file MachineScheduler.h.

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

include/llvm/CodeGen/MachineScheduler.h
lib/CodeGen/MachineScheduler.cpp

Public Types

Public Member Functions

Public Attributes

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ SchedBoundary()

◆ ~SchedBoundary()

Member Function Documentation

◆ bumpCycle()

◆ bumpNode()

◆ checkHazard()

◆ countResource()

◆ dumpScheduledState()

◆ findMaxLatency()

◆ getCriticalCount()

◆ getCurrCycle()

◆ getCurrMOps()

◆ getDependentLatency()

◆ getExecutedCount()

◆ getLatencyStallCycles()

◆ getNextResourceCycle()

◆ getOtherResourceCount()

◆ getResourceCount()

◆ getScheduledLatency()

◆ getUnscheduledLatency()

◆ getZoneCritResIdx()

◆ incExecutedResources()

◆ init()

◆ isResourceLimited()

◆ isTop()

◆ pickOnlyChoice()

◆ releaseNode()

◆ releasePending()

◆ removeReady()

◆ reset()

Member Data Documentation

◆ Available

◆ DAG

◆ HazardRec

◆ Pending

◆ Rem

◆ SchedModel