LLVM  4.0.0
Public Types | Public Member Functions | Public Attributes | List of all members
llvm::SchedBoundary Class Reference

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

#include <MachineScheduler.h>

Collaboration diagram for llvm::SchedBoundary:
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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...
 
SUnitpickOnlyChoice ()
 Call this before applying any other heuristics to the Available queue. More...
 
void dumpScheduledState ()
 

Public Attributes

ScheduleDAGMIDAG
 
const TargetSchedModelSchedModel
 
SchedRemainderRem
 
ReadyQueue Available
 
ReadyQueue Pending
 
ScheduleHazardRecognizerHazardRec
 

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 592 of file MachineScheduler.h.

Member Enumeration Documentation

anonymous enum

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

Enumerator
TopQID 
BotQID 
LogMaxQID 

Definition at line 595 of file MachineScheduler.h.

Constructor & Destructor Documentation

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 667 of file MachineScheduler.h.

References reset().

SchedBoundary::~SchedBoundary ( )

Definition at line 1824 of file MachineScheduler.cpp.

References HazardRec.

Member Function Documentation

void SchedBoundary::bumpCycle ( unsigned  NextCycle)
void SchedBoundary::bumpNode ( SUnit SU)
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 arbitraty 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 1935 of file MachineScheduler.cpp.

References llvm::dbgs(), DEBUG, llvm::ScheduleHazardRecognizer::getHazardType(), llvm::SUnit::getInstr(), llvm::TargetSchedModel::getIssueWidth(), getNextResourceCycle(), llvm::TargetSchedModel::getNumMicroOps(), llvm::TargetSchedModel::getResourceName(), llvm::ScheduleDAGInstrs::getSchedClass(), llvm::TargetSchedModel::getWriteProcResBegin(), llvm::TargetSchedModel::getWriteProcResEnd(), llvm::TargetSchedModel::hasInstrSchedModel(), llvm::SUnit::hasReservedResource, HazardRec, llvm::ScheduleHazardRecognizer::isEnabled(), llvm::SUnit::NodeNum, llvm::ScheduleHazardRecognizer::NoHazard, llvm::PPCISD::SC, and SchedModel.

Referenced by pickOnlyChoice(), releaseNode(), and releasePending().

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

Add the given processor resource to this scheduled zone.

Parameters
Cyclesindicates 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 2091 of file MachineScheduler.cpp.

References assert(), llvm::dbgs(), DEBUG, getCriticalCount(), llvm::TargetSchedModel::getLatencyFactor(), getNextResourceCycle(), llvm::TargetSchedModel::getProcResource(), getResourceCount(), llvm::TargetSchedModel::getResourceFactor(), llvm::TargetSchedModel::getResourceName(), incExecutedResources(), llvm::MCProcResourceDesc::Name, Rem, llvm::SchedRemainder::RemainingCounts, and SchedModel.

Referenced by bumpNode().

void SchedBoundary::dumpScheduledState ( )
unsigned SchedBoundary::findMaxLatency ( ArrayRef< SUnit * >  ReadySUs)
unsigned llvm::SchedBoundary::getCriticalCount ( ) const
inline

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

Definition at line 711 of file MachineScheduler.h.

References llvm::TargetSchedModel::getMicroOpFactor(), getResourceCount(), and SchedModel.

Referenced by bumpCycle(), bumpNode(), and countResource().

unsigned llvm::SchedBoundary::getCurrCycle ( ) const
inline

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

Definition at line 686 of file MachineScheduler.h.

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

unsigned llvm::SchedBoundary::getCurrMOps ( ) const
inline

Micro-ops issued in the current cycle.

Definition at line 689 of file MachineScheduler.h.

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

unsigned llvm::SchedBoundary::getDependentLatency ( ) const
inline

Definition at line 692 of file MachineScheduler.h.

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

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 720 of file MachineScheduler.h.

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

Referenced by dumpScheduledState().

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 1898 of file MachineScheduler.cpp.

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

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

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

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

Definition at line 1911 of file MachineScheduler.cpp.

References InvalidCycle, and isTop().

Referenced by bumpNode(), checkHazard(), and countResource().

unsigned SchedBoundary::getOtherResourceCount ( unsigned OtherCritIdx)
unsigned llvm::SchedBoundary::getResourceCount ( unsigned  ResIdx) const
inline
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 697 of file MachineScheduler.h.

Referenced by bumpCycle(), bumpNode(), and tryLatency().

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

Definition at line 701 of file MachineScheduler.h.

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

Referenced by findMaxLatency().

unsigned llvm::SchedBoundary::getZoneCritResIdx ( ) const
inline

Definition at line 725 of file MachineScheduler.h.

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

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

Definition at line 2077 of file MachineScheduler.cpp.

Referenced by countResource().

void SchedBoundary::init ( ScheduleDAGMI dag,
const TargetSchedModel smodel,
SchedRemainder rem 
)
bool llvm::SchedBoundary::isResourceLimited ( ) const
inline

Definition at line 728 of file MachineScheduler.h.

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

bool llvm::SchedBoundary::isTop ( ) const
inline
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 2294 of file MachineScheduler.cpp.

References Available, llvm::ReadyQueue::begin(), bumpCycle(), checkHazard(), DEBUG, llvm::ReadyQueue::dump(), llvm::ReadyQueue::empty(), llvm::ReadyQueue::end(), I, i, Pending, llvm::ReadyQueue::push(), releasePending(), llvm::ReadyQueue::remove(), and llvm::ReadyQueue::size().

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

void SchedBoundary::releaseNode ( SUnit SU,
unsigned  ReadyCycle 
)
void SchedBoundary::releasePending ( )
void SchedBoundary::removeReady ( SUnit SU)

Remove SU from the ready set for this boundary.

Definition at line 2282 of file MachineScheduler.cpp.

References assert(), Available, llvm::ReadyQueue::find(), llvm::ReadyQueue::isInQueue(), Pending, and llvm::ReadyQueue::remove().

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

void SchedBoundary::reset ( )

Member Data Documentation

ReadyQueue llvm::SchedBoundary::Available
ScheduleDAGMI* llvm::SchedBoundary::DAG

Definition at line 601 of file MachineScheduler.h.

ScheduleHazardRecognizer* llvm::SchedBoundary::HazardRec

Definition at line 608 of file MachineScheduler.h.

Referenced by bumpCycle(), bumpNode(), checkHazard(), reset(), and ~SchedBoundary().

ReadyQueue llvm::SchedBoundary::Pending
SchedRemainder* llvm::SchedBoundary::Rem

Definition at line 603 of file MachineScheduler.h.

Referenced by bumpNode(), countResource(), getOtherResourceCount(), and init().

const TargetSchedModel* llvm::SchedBoundary::SchedModel

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