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llvm / llvm-project / llvm / 0f046bf7abbdfa40aeef31d86835b7adb530511f / . / lib / Target / AMDGPU / AMDGPUIGroupLP.cpp
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//===--- AMDGPUIGroupLP.cpp - AMDGPU IGroupLP ------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// \file This file defines a set of schedule DAG mutations that can be used to
// override default scheduler behavior to enforce specific scheduling patterns.
// They should be used in cases where runtime performance considerations such as
// inter-wavefront interactions, mean that compile-time heuristics cannot
// predict the optimal instruction ordering, or in kernels where optimum
// instruction scheduling is important enough to warrant manual intervention.
//
//===----------------------------------------------------------------------===//
#include "AMDGPUIGroupLP.h"
#include "AMDGPUTargetMachine.h"
#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
#include "SIInstrInfo.h"
#include "SIMachineFunctionInfo.h"
#include "llvm/ADT/BitmaskEnum.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/MachineScheduler.h"
#include "llvm/CodeGen/TargetOpcodes.h"
using namespace llvm;
#define DEBUG_TYPE "igrouplp"
namespace {
static cl::opt<bool> EnableExactSolver(
"amdgpu-igrouplp-exact-solver", cl::Hidden,
cl::desc("Whether to use the exponential time solver to fit "
"the instructions to the pipeline as closely as "
"possible."),
cl::init(false));
static cl::opt<unsigned> CutoffForExact(
"amdgpu-igrouplp-exact-solver-cutoff", cl::init(0), cl::Hidden,
cl::desc("The maximum number of scheduling group conflicts "
"which we attempt to solve with the exponential time "
"exact solver. Problem sizes greater than this will"
"be solved by the less accurate greedy algorithm. Selecting "
"solver by size is superseded by manually selecting "
"the solver (e.g. by amdgpu-igrouplp-exact-solver"));
static cl::opt<uint64_t> MaxBranchesExplored(
"amdgpu-igrouplp-exact-solver-max-branches", cl::init(0), cl::Hidden,
cl::desc("The amount of branches that we are willing to explore with"
"the exact algorithm before giving up."));
static cl::opt<bool> UseCostHeur(
"amdgpu-igrouplp-exact-solver-cost-heur", cl::init(true), cl::Hidden,
cl::desc("Whether to use the cost heuristic to make choices as we "
"traverse the search space using the exact solver. Defaulted "
"to on, and if turned off, we will use the node order -- "
"attempting to put the later nodes in the later sched groups. "
"Experimentally, results are mixed, so this should be set on a "
"case-by-case basis."));
// Components of the mask that determines which instruction types may be may be
// classified into a SchedGroup.
enum class SchedGroupMask {
NONE = 0u,
ALU = 1u << 0,
VALU = 1u << 1,
SALU = 1u << 2,
MFMA = 1u << 3,
VMEM = 1u << 4,
VMEM_READ = 1u << 5,
VMEM_WRITE = 1u << 6,
DS = 1u << 7,
DS_READ = 1u << 8,
DS_WRITE = 1u << 9,
TRANS = 1u << 10,
ALL = ALU | VALU | SALU | MFMA | VMEM | VMEM_READ | VMEM_WRITE | DS |
DS_READ | DS_WRITE | TRANS,
LLVM_MARK_AS_BITMASK_ENUM(/* LargestFlag = */ ALL)
};
class SchedGroup;
// InstructionRule class is used to enact a filter which determines whether or
// not an SU maps to a given SchedGroup. It contains complementary data
// structures (e.g Cache) to help those filters.
class InstructionRule {
protected:
const SIInstrInfo *TII;
unsigned SGID;
// A cache made available to the Filter to store SUnits for subsequent
// invocations of the Filter
std::optional<SmallVector<SUnit *, 4>> Cache;
public:
virtual bool
apply(const SUnit *, const ArrayRef<SUnit *>,
SmallVectorImpl<SchedGroup> &) {
return true;
};
InstructionRule(const SIInstrInfo *TII, unsigned SGID,
bool NeedsCache = false)
: TII(TII), SGID(SGID) {
if (NeedsCache) {
Cache = SmallVector<SUnit *, 4>();
}
}
virtual ~InstructionRule() = default;
};
typedef DenseMap<SUnit *, SmallVector<int, 4>> SUnitsToCandidateSGsMap;
// Classify instructions into groups to enable fine tuned control over the
// scheduler. These groups may be more specific than current SchedModel
// instruction classes.
class SchedGroup {
private:
// Mask that defines which instruction types can be classified into this
// SchedGroup. The instruction types correspond to the mask from SCHED_BARRIER
// and SCHED_GROUP_BARRIER.
SchedGroupMask SGMask;
// Maximum number of SUnits that can be added to this group.
std::optional<unsigned> MaxSize;
// SchedGroups will only synchronize with other SchedGroups that have the same
// SyncID.
int SyncID = 0;
// SGID is used to map instructions to candidate SchedGroups
unsigned SGID;
// The different rules each instruction in this SchedGroup must conform to
SmallVector<std::shared_ptr<InstructionRule>, 4> Rules;
// Count of the number of created SchedGroups, used to initialize SGID.
static unsigned NumSchedGroups;
// Try to add and edge from SU A to SU B.
bool tryAddEdge(SUnit *A, SUnit *B);
// Use SGMask to determine whether we can classify MI as a member of this
// SchedGroup object.
bool canAddMI(const MachineInstr &MI) const;
public:
// Collection of SUnits that are classified as members of this group.
SmallVector<SUnit *, 32> Collection;
ScheduleDAGInstrs *DAG;
const SIInstrInfo *TII;
// Returns true if SU can be added to this SchedGroup.
bool canAddSU(SUnit &SU) const;
// Add DAG dependencies from all SUnits in this SchedGroup and this SU. If
// MakePred is true, SU will be a predecessor of the SUnits in this
// SchedGroup, otherwise SU will be a successor.
void link(SUnit &SU, bool MakePred = false);
// Add DAG dependencies and track which edges are added, and the count of
// missed edges
int link(SUnit &SU, bool MakePred,
std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges);
// Add DAG dependencies from all SUnits in this SchedGroup and this SU.
// Use the predicate to determine whether SU should be a predecessor (P =
// true) or a successor (P = false) of this SchedGroup.
void link(SUnit &SU, function_ref<bool(const SUnit *A, const SUnit *B)> P);
// Add DAG dependencies such that SUnits in this group shall be ordered
// before SUnits in OtherGroup.
void link(SchedGroup &OtherGroup);
// Returns true if no more instructions may be added to this group.
bool isFull() const { return MaxSize && Collection.size() >= *MaxSize; }
// Append a constraint that SUs must meet in order to fit into this
// SchedGroup. Since many rules involve the relationship between a SchedGroup
// and the SUnits in other SchedGroups, rules are checked at Pipeline Solve
// time (rather than SchedGroup init time.)
void addRule(std::shared_ptr<InstructionRule> NewRule) {
Rules.push_back(NewRule);
}
// Returns true if the SU matches all rules
bool allowedByRules(const SUnit *SU,
SmallVectorImpl<SchedGroup> &SyncPipe) const {
if (Rules.empty())
return true;
for (size_t I = 0; I < Rules.size(); I++) {
auto TheRule = Rules[I].get();
if (!TheRule->apply(SU, Collection, SyncPipe)) {
return false;
}
}
return true;
}
// Add SU to the SchedGroup.
void add(SUnit &SU) {
LLVM_DEBUG(dbgs() << "For SchedGroup with mask "
<< format_hex((int)SGMask, 10, true) << " adding "
<< *SU.getInstr());
Collection.push_back(&SU);
}
// Remove last element in the SchedGroup
void pop() { Collection.pop_back(); }
// Identify and add all relevant SUs from the DAG to this SchedGroup.
void initSchedGroup();
// Add instructions to the SchedGroup bottom up starting from RIter.
// PipelineInstrs is a set of instructions that should not be added to the
// SchedGroup even when the other conditions for adding it are satisfied.
// RIter will be added to the SchedGroup as well, and dependencies will be
// added so that RIter will always be scheduled at the end of the group.
void initSchedGroup(std::vector<SUnit>::reverse_iterator RIter,
SUnitsToCandidateSGsMap &SyncedInstrs);
void initSchedGroup(SUnitsToCandidateSGsMap &SyncedInstrs);
int getSyncID() { return SyncID; }
int getSGID() { return SGID; }
SchedGroupMask getMask() { return SGMask; }
SchedGroup(SchedGroupMask SGMask, std::optional<unsigned> MaxSize,
ScheduleDAGInstrs *DAG, const SIInstrInfo *TII)
: SGMask(SGMask), MaxSize(MaxSize), DAG(DAG), TII(TII) {
SGID = NumSchedGroups++;
}
SchedGroup(SchedGroupMask SGMask, std::optional<unsigned> MaxSize, int SyncID,
ScheduleDAGInstrs *DAG, const SIInstrInfo *TII)
: SGMask(SGMask), MaxSize(MaxSize), SyncID(SyncID), DAG(DAG), TII(TII) {
SGID = NumSchedGroups++;
}
};
// Remove all existing edges from a SCHED_BARRIER or SCHED_GROUP_BARRIER.
static void resetEdges(SUnit &SU, ScheduleDAGInstrs *DAG) {
assert(SU.getInstr()->getOpcode() == AMDGPU::SCHED_BARRIER ||
SU.getInstr()->getOpcode() == AMDGPU::SCHED_GROUP_BARRIER ||
SU.getInstr()->getOpcode() == AMDGPU::IGLP_OPT);
while (!SU.Preds.empty())
for (auto &P : SU.Preds)
SU.removePred(P);
while (!SU.Succs.empty())
for (auto &S : SU.Succs)
for (auto &SP : S.getSUnit()->Preds)
if (SP.getSUnit() == &SU)
S.getSUnit()->removePred(SP);
}
typedef std::pair<SUnit *, SmallVector<int, 4>> SUToCandSGsPair;
typedef SmallVector<SUToCandSGsPair, 4> SUsToCandSGsVec;
// The PipelineSolver is used to assign SUnits to SchedGroups in a pipeline
// in non-trivial cases. For example, if the requested pipeline is
// {VMEM_READ, VALU, MFMA, VMEM_READ} and we encounter a VMEM_READ instruction
// in the DAG, then we will have an instruction that can not be trivially
// assigned to a SchedGroup. The PipelineSolver class implements two algorithms
// to find a good solution to the pipeline -- a greedy algorithm and an exact
// algorithm. The exact algorithm has an exponential time complexity and should
// only be used for small sized problems or medium sized problems where an exact
// solution is highly desired.
class PipelineSolver {
ScheduleDAGMI *DAG;
// Instructions that can be assigned to multiple SchedGroups
DenseMap<int, SUnitsToCandidateSGsMap> SyncedInstrs;
SmallVector<SUsToCandSGsVec, 4> PipelineInstrs;
DenseMap<int, SmallVector<SchedGroup, 4>> SyncedSchedGroups;
// The current working pipeline
SmallVector<SmallVector<SchedGroup, 4>, 4> CurrPipeline;
// The pipeline that has the best solution found so far
SmallVector<SmallVector<SchedGroup, 4>, 4> BestPipeline;
// Whether or not we actually have any SyncedInstrs to try to solve.
bool NeedsSolver = false;
// Compute an estimate of the size of search tree -- the true size is
// the product of each conflictedInst.Matches.size() across all SyncPipelines
unsigned computeProblemSize();
// The cost penalty of not assigning a SU to a SchedGroup
int MissPenalty = 0;
// Costs in terms of the number of edges we are unable to add
int BestCost = -1;
int CurrCost = 0;
// Index pointing to the conflicting instruction that is currently being
// fitted
int CurrConflInstNo = 0;
// Index to the pipeline that is currently being fitted
int CurrSyncGroupIdx = 0;
// The first non trivial pipeline
int BeginSyncGroupIdx = 0;
// How many branches we have explored
uint64_t BranchesExplored = 0;
// The direction in which we process the candidate SchedGroups per SU
bool IsBottomUp = 1;
// Update indices to fit next conflicting instruction
void advancePosition();
// Recede indices to attempt to find better fit for previous conflicting
// instruction
void retreatPosition();
// The exponential time algorithm which finds the provably best fit
bool solveExact();
// The polynomial time algorithm which attempts to find a good fit
bool solveGreedy();
// Find the best SchedGroup for the current SU using the heuristic given all
// current information. One step in the greedy algorithm. Templated against
// the SchedGroup iterator (either reverse or forward).
template <typename T>
void greedyFind(std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges, T I,
T E);
// Whether or not the current solution is optimal
bool checkOptimal();
// Populate the ready list, prioiritizing fewest missed edges first
// Templated against the SchedGroup iterator (either reverse or forward).
template <typename T>
void populateReadyList(SmallVectorImpl<std::pair<int, int>> &ReadyList, T I,
T E);
// Add edges corresponding to the SchedGroups as assigned by solver
void makePipeline();
// Link the SchedGroups in the best found pipeline.
// Tmplated against the SchedGroup iterator (either reverse or forward).
template <typename T> void linkSchedGroups(T I, T E);
// Add the edges from the SU to the other SchedGroups in pipeline, and
// return the number of edges missed.
int addEdges(SmallVectorImpl<SchedGroup> &SyncPipeline, SUnit *SU, int SGID,
std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges);
/// Link the pipeline as if \p SU was in the SchedGroup with ID \p SGID. It
/// returns the cost (in terms of missed pipeline edges), and tracks the edges
/// added in \p AddedEdges
template <typename T>
int linkSUnit(SUnit *SU, int SGID,
std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges, T I, T E);
/// Remove the edges passed via \p AddedEdges
void removeEdges(const std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges);
// Convert the passed in maps to arrays for bidirectional iterators
void convertSyncMapsToArrays();
void reset();
public:
// Invoke the solver to map instructions to instruction groups. Heuristic &&
// command-line-option determines to use exact or greedy algorithm.
void solve();
PipelineSolver(DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
ScheduleDAGMI *DAG, bool IsBottomUp = 1)
: DAG(DAG), SyncedInstrs(SyncedInstrs),
SyncedSchedGroups(SyncedSchedGroups), IsBottomUp(IsBottomUp) {
for (auto &PipelineInstrs : SyncedInstrs) {
if (PipelineInstrs.second.size() > 0) {
NeedsSolver = true;
break;
}
}
if (!NeedsSolver)
return;
convertSyncMapsToArrays();
CurrPipeline = BestPipeline;
while (static_cast<size_t>(BeginSyncGroupIdx) < PipelineInstrs.size() &&
PipelineInstrs[BeginSyncGroupIdx].size() == 0)
++BeginSyncGroupIdx;
if (static_cast<size_t>(BeginSyncGroupIdx) >= PipelineInstrs.size())
return;
}
};
void PipelineSolver::reset() {
for (auto &SyncPipeline : CurrPipeline) {
for (auto &SG : SyncPipeline) {
SmallVector<SUnit *, 32> TempCollection = SG.Collection;
SG.Collection.clear();
auto SchedBarr = llvm::find_if(TempCollection, [](SUnit *SU) {
return SU->getInstr()->getOpcode() == AMDGPU::SCHED_GROUP_BARRIER;
});
if (SchedBarr != TempCollection.end())
SG.Collection.push_back(*SchedBarr);
}
}
CurrSyncGroupIdx = BeginSyncGroupIdx;
CurrConflInstNo = 0;
CurrCost = 0;
}
void PipelineSolver::convertSyncMapsToArrays() {
for (auto &SyncPipe : SyncedSchedGroups) {
BestPipeline.insert(BestPipeline.begin(), SyncPipe.second);
}
int PipelineIDx = SyncedInstrs.size() - 1;
PipelineInstrs.resize(SyncedInstrs.size());
for (auto &SyncInstrMap : SyncedInstrs) {
for (auto &SUsToCandSGs : SyncInstrMap.second) {
if (PipelineInstrs[PipelineIDx].size() == 0) {
PipelineInstrs[PipelineIDx].push_back(
std::pair(SUsToCandSGs.first, SUsToCandSGs.second));
continue;
}
auto SortPosition = PipelineInstrs[PipelineIDx].begin();
// Insert them in sorted order -- this allows for good parsing order in
// the greedy algorithm
while (SortPosition != PipelineInstrs[PipelineIDx].end() &&
SUsToCandSGs.first->NodeNum > SortPosition->first->NodeNum)
++SortPosition;
PipelineInstrs[PipelineIDx].insert(
SortPosition, std::pair(SUsToCandSGs.first, SUsToCandSGs.second));
}
--PipelineIDx;
}
}
template <typename T> void PipelineSolver::linkSchedGroups(T I, T E) {
for (; I != E; ++I) {
auto &GroupA = *I;
for (auto J = std::next(I); J != E; ++J) {
auto &GroupB = *J;
GroupA.link(GroupB);
}
}
}
void PipelineSolver::makePipeline() {
// Preserve the order of barrier for subsequent SchedGroupBarrier mutations
for (auto &SyncPipeline : BestPipeline) {
LLVM_DEBUG(dbgs() << "Printing SchedGroups\n");
for (auto &SG : SyncPipeline) {
LLVM_DEBUG(dbgs() << "SchedGroup with SGID " << SG.getSGID()
<< " has: \n");
SUnit *SGBarr = nullptr;
for (auto &SU : SG.Collection) {
if (SU->getInstr()->getOpcode() == AMDGPU::SCHED_GROUP_BARRIER)
SGBarr = SU;
LLVM_DEBUG(dbgs() << "SU(" << SU->NodeNum << ")\n");
}
// Command line requested IGroupLP doesn't have SGBarr
if (!SGBarr)
continue;
resetEdges(*SGBarr, DAG);
SG.link(*SGBarr, false);
}
}
for (auto &SyncPipeline : BestPipeline) {
IsBottomUp ? linkSchedGroups(SyncPipeline.rbegin(), SyncPipeline.rend())
: linkSchedGroups(SyncPipeline.begin(), SyncPipeline.end());
}
}
template <typename T>
int PipelineSolver::linkSUnit(
SUnit *SU, int SGID, std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges,
T I, T E) {
bool MakePred = false;
int AddedCost = 0;
for (; I < E; ++I) {
if (I->getSGID() == SGID) {
MakePred = true;
continue;
}
auto Group = *I;
AddedCost += Group.link(*SU, MakePred, AddedEdges);
assert(AddedCost >= 0);
}
return AddedCost;
}
int PipelineSolver::addEdges(
SmallVectorImpl<SchedGroup> &SyncPipeline, SUnit *SU, int SGID,
std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges) {
// For IsBottomUp, the first SchedGroup in SyncPipeline contains the
// instructions that are the ultimate successors in the resultant mutation.
// Therefore, in such a configuration, the SchedGroups occurring before the
// candidate SGID are successors of the candidate SchedGroup, thus the current
// SU should be linked as a predecessor to SUs in those SchedGroups. The
// opposite is true if !IsBottomUp. IsBottomUp occurs in the case of multiple
// SCHED_GROUP_BARRIERS, or if a user specifies IGLP_OPT SchedGroups using
// IsBottomUp (in reverse).
return IsBottomUp ? linkSUnit(SU, SGID, AddedEdges, SyncPipeline.rbegin(),
SyncPipeline.rend())
: linkSUnit(SU, SGID, AddedEdges, SyncPipeline.begin(),
SyncPipeline.end());
}
void PipelineSolver::removeEdges(
const std::vector<std::pair<SUnit *, SUnit *>> &EdgesToRemove) {
// Only remove the edges that we have added when testing
// the fit.
for (auto &PredSuccPair : EdgesToRemove) {
SUnit *Pred = PredSuccPair.first;
SUnit *Succ = PredSuccPair.second;
auto Match = llvm::find_if(
Succ->Preds, [&Pred](SDep &P) { return P.getSUnit() == Pred; });
if (Match != Succ->Preds.end()) {
assert(Match->isArtificial());
Succ->removePred(*Match);
}
}
}
void PipelineSolver::advancePosition() {
++CurrConflInstNo;
if (static_cast<size_t>(CurrConflInstNo) >=
PipelineInstrs[CurrSyncGroupIdx].size()) {
CurrConflInstNo = 0;
++CurrSyncGroupIdx;
// Advance to next non-trivial pipeline
while (static_cast<size_t>(CurrSyncGroupIdx) < PipelineInstrs.size() &&
PipelineInstrs[CurrSyncGroupIdx].size() == 0)
++CurrSyncGroupIdx;
}
}
void PipelineSolver::retreatPosition() {
assert(CurrConflInstNo >= 0);
assert(CurrSyncGroupIdx >= 0);
if (CurrConflInstNo > 0) {
--CurrConflInstNo;
return;
}
if (CurrConflInstNo == 0) {
// If we return to the starting position, we have explored
// the entire tree
if (CurrSyncGroupIdx == BeginSyncGroupIdx)
return;
--CurrSyncGroupIdx;
// Go to previous non-trivial pipeline
while (PipelineInstrs[CurrSyncGroupIdx].size() == 0)
--CurrSyncGroupIdx;
CurrConflInstNo = PipelineInstrs[CurrSyncGroupIdx].size() - 1;
}
}
bool PipelineSolver::checkOptimal() {
if (static_cast<size_t>(CurrSyncGroupIdx) == PipelineInstrs.size()) {
if (BestCost == -1 || CurrCost < BestCost) {
BestPipeline = CurrPipeline;
BestCost = CurrCost;
LLVM_DEBUG(dbgs() << "Found Fit with cost " << BestCost << "\n");
}
assert(BestCost >= 0);
}
bool DoneExploring = false;
if (MaxBranchesExplored > 0 && BranchesExplored >= MaxBranchesExplored)
DoneExploring = true;
return (DoneExploring || BestCost == 0);
}
template <typename T>
void PipelineSolver::populateReadyList(
SmallVectorImpl<std::pair<int, int>> &ReadyList, T I, T E) {
SUToCandSGsPair CurrSU = PipelineInstrs[CurrSyncGroupIdx][CurrConflInstNo];
auto SyncPipeline = CurrPipeline[CurrSyncGroupIdx];
assert(CurrSU.second.size() >= 1);
for (; I != E; ++I) {
std::vector<std::pair<SUnit *, SUnit *>> AddedEdges;
int CandSGID = *I;
SchedGroup *Match = llvm::find_if(SyncPipeline, [CandSGID](SchedGroup &SG) {
return SG.getSGID() == CandSGID;
});
assert(Match);
if (UseCostHeur) {
if (Match->isFull()) {
ReadyList.push_back(std::pair(*I, MissPenalty));
continue;
}
int TempCost = addEdges(SyncPipeline, CurrSU.first, CandSGID, AddedEdges);
ReadyList.push_back(std::pair(*I, TempCost));
removeEdges(AddedEdges);
} else
ReadyList.push_back(std::pair(*I, -1));
}
if (UseCostHeur) {
std::sort(ReadyList.begin(), ReadyList.end(),
[](std::pair<int, int> A, std::pair<int, int> B) {
return A.second < B.second;
});
}
assert(ReadyList.size() == CurrSU.second.size());
}
bool PipelineSolver::solveExact() {
if (checkOptimal())
return true;
if (static_cast<size_t>(CurrSyncGroupIdx) == PipelineInstrs.size())
return false;
assert(static_cast<size_t>(CurrSyncGroupIdx) < PipelineInstrs.size());
assert(static_cast<size_t>(CurrConflInstNo) <
PipelineInstrs[CurrSyncGroupIdx].size());
SUToCandSGsPair CurrSU = PipelineInstrs[CurrSyncGroupIdx][CurrConflInstNo];
LLVM_DEBUG(dbgs() << "Fitting SU(" << CurrSU.first->NodeNum
<< ") in Pipeline # " << CurrSyncGroupIdx << "\n");
// SchedGroup -> Cost pairs
SmallVector<std::pair<int, int>, 4> ReadyList;
// Prioritize the candidate sched groups in terms of lowest cost first
IsBottomUp ? populateReadyList(ReadyList, CurrSU.second.rbegin(),
CurrSU.second.rend())
: populateReadyList(ReadyList, CurrSU.second.begin(),
CurrSU.second.end());
auto I = ReadyList.begin();
auto E = ReadyList.end();
for (; I != E; ++I) {
// If we are trying SGs in least cost order, and the current SG is cost
// infeasible, then all subsequent SGs will also be cost infeasible, so we
// can prune.
if (BestCost != -1 && (CurrCost + I->second > BestCost))
return false;
int CandSGID = I->first;
int AddedCost = 0;
std::vector<std::pair<SUnit *, SUnit *>> AddedEdges;
auto &SyncPipeline = CurrPipeline[CurrSyncGroupIdx];
SchedGroup *Match;
for (auto &SG : SyncPipeline) {
if (SG.getSGID() == CandSGID)
Match = &SG;
}
if (Match->isFull())
continue;
if (!Match->allowedByRules(CurrSU.first, SyncPipeline))
continue;
LLVM_DEBUG(dbgs() << "Assigning to SchedGroup with Mask "
<< (int)Match->getMask() << "and ID " << CandSGID
<< "\n");
Match->add(*CurrSU.first);
AddedCost = addEdges(SyncPipeline, CurrSU.first, CandSGID, AddedEdges);
LLVM_DEBUG(dbgs() << "Cost of Assignment: " << AddedCost << "\n");
CurrCost += AddedCost;
advancePosition();
++BranchesExplored;
bool FinishedExploring = false;
// If the Cost after adding edges is greater than a known solution,
// backtrack
if (CurrCost < BestCost || BestCost == -1) {
if (solveExact()) {
FinishedExploring = BestCost != 0;
if (!FinishedExploring)
return true;
}
}
retreatPosition();
CurrCost -= AddedCost;
removeEdges(AddedEdges);
Match->pop();
CurrPipeline[CurrSyncGroupIdx] = SyncPipeline;
if (FinishedExploring)
return true;
}
// Try the pipeline where the current instruction is omitted
// Potentially if we omit a problematic instruction from the pipeline,
// all the other instructions can nicely fit.
CurrCost += MissPenalty;
advancePosition();
LLVM_DEBUG(dbgs() << "NOT Assigned (" << CurrSU.first->NodeNum << ")\n");
bool FinishedExploring = false;
if (CurrCost < BestCost || BestCost == -1) {
if (solveExact()) {
bool FinishedExploring = BestCost != 0;
if (!FinishedExploring)
return true;
}
}
retreatPosition();
CurrCost -= MissPenalty;
return FinishedExploring;
}
template <typename T>
void PipelineSolver::greedyFind(
std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges, T I, T E) {
SUToCandSGsPair CurrSU = PipelineInstrs[CurrSyncGroupIdx][CurrConflInstNo];
int BestNodeCost = -1;
int TempCost;
SchedGroup *BestGroup = nullptr;
int BestGroupID = -1;
auto &SyncPipeline = CurrPipeline[CurrSyncGroupIdx];
LLVM_DEBUG(dbgs() << "Fitting SU(" << CurrSU.first->NodeNum
<< ") in Pipeline # " << CurrSyncGroupIdx << "\n");
// Since we have added the potential SchedGroups from bottom up, but
// traversed the DAG from top down, parse over the groups from last to
// first. If we fail to do this for the greedy algorithm, the solution will
// likely not be good in more complex cases.
for (; I != E; ++I) {
std::vector<std::pair<SUnit *, SUnit *>> AddedEdges;
int CandSGID = *I;
SchedGroup *Match = llvm::find_if(SyncPipeline, [CandSGID](SchedGroup &SG) {
return SG.getSGID() == CandSGID;
});
assert(Match);
LLVM_DEBUG(dbgs() << "Trying SGID # " << CandSGID << " with Mask "
<< (int)Match->getMask() << "\n");
if (Match->isFull()) {
LLVM_DEBUG(dbgs() << "SGID # " << CandSGID << " is full\n");
continue;
}
if (!Match->allowedByRules(CurrSU.first, SyncPipeline)) {
LLVM_DEBUG(dbgs() << "SGID # " << CandSGID << " has conflicting rule\n");
continue;
}
TempCost = addEdges(SyncPipeline, CurrSU.first, CandSGID, AddedEdges);
LLVM_DEBUG(dbgs() << "Cost of Group " << TempCost << "\n");
if (TempCost < BestNodeCost || BestNodeCost == -1) {
BestGroup = Match;
BestNodeCost = TempCost;
BestGroupID = CandSGID;
}
removeEdges(AddedEdges);
if (BestNodeCost == 0)
break;
}
if (BestGroupID != -1) {
BestGroup->add(*CurrSU.first);
addEdges(SyncPipeline, CurrSU.first, BestGroupID, AddedEdges);
LLVM_DEBUG(dbgs() << "Best Group has ID: " << BestGroupID << " and Mask"
<< (int)BestGroup->getMask() << "\n");
BestCost += TempCost;
} else
BestCost += MissPenalty;
CurrPipeline[CurrSyncGroupIdx] = SyncPipeline;
}
bool PipelineSolver::solveGreedy() {
BestCost = 0;
std::vector<std::pair<SUnit *, SUnit *>> AddedEdges;
while (static_cast<size_t>(CurrSyncGroupIdx) < PipelineInstrs.size()) {
SUToCandSGsPair CurrSU = PipelineInstrs[CurrSyncGroupIdx][CurrConflInstNo];
IsBottomUp
? greedyFind(AddedEdges, CurrSU.second.rbegin(), CurrSU.second.rend())
: greedyFind(AddedEdges, CurrSU.second.begin(), CurrSU.second.end());
advancePosition();
}
BestPipeline = CurrPipeline;
removeEdges(AddedEdges);
return false;
}
unsigned PipelineSolver::computeProblemSize() {
unsigned ProblemSize = 0;
for (auto &PipeConflicts : PipelineInstrs) {
ProblemSize += PipeConflicts.size();
}
return ProblemSize;
}
void PipelineSolver::solve() {
if (!NeedsSolver)
return;
unsigned ProblemSize = computeProblemSize();
assert(ProblemSize > 0);
bool BelowCutoff = (CutoffForExact > 0) && ProblemSize <= CutoffForExact;
MissPenalty = (ProblemSize / 2) + 1;
LLVM_DEBUG(DAG->dump());
if (EnableExactSolver || BelowCutoff) {
LLVM_DEBUG(dbgs() << "Starting Greedy pipeline solver\n");
solveGreedy();
reset();
LLVM_DEBUG(dbgs() << "Greedy produced best cost of " << BestCost << "\n");
if (BestCost > 0) {
LLVM_DEBUG(dbgs() << "Starting EXACT pipeline solver\n");
solveExact();
LLVM_DEBUG(dbgs() << "Exact produced best cost of " << BestCost << "\n");
}
} else { // Use the Greedy Algorithm by default
LLVM_DEBUG(dbgs() << "Starting GREEDY pipeline solver\n");
solveGreedy();
}
makePipeline();
LLVM_DEBUG(dbgs() << "After applying mutation\n");
LLVM_DEBUG(DAG->dump());
}
enum IGLPStrategyID : int {
MFMASmallGemmOptID = 0,
MFMASmallGemmSingleWaveOptID = 1,
MFMAExpInterleave = 2
};
// Implement a IGLP scheduling strategy.
class IGLPStrategy {
protected:
ScheduleDAGInstrs *DAG;
const SIInstrInfo *TII;
public:
/// Add SchedGroups to \p SyncedSchedGroups to implement this Strategy.
virtual bool applyIGLPStrategy(
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
AMDGPU::SchedulingPhase Phase) = 0;
// Returns true if this strategy should be applied to a ScheduleDAG.
virtual bool shouldApplyStrategy(ScheduleDAGInstrs *DAG,
AMDGPU::SchedulingPhase Phase) = 0;
bool IsBottomUp = 1;
IGLPStrategy(ScheduleDAGInstrs *DAG, const SIInstrInfo *TII)
: DAG(DAG), TII(TII) {}
virtual ~IGLPStrategy() = default;
};
class MFMASmallGemmOpt final : public IGLPStrategy {
private:
public:
bool applyIGLPStrategy(
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
AMDGPU::SchedulingPhase Phase) override;
bool shouldApplyStrategy(ScheduleDAGInstrs *DAG,
AMDGPU::SchedulingPhase Phase) override {
return true;
}
MFMASmallGemmOpt(ScheduleDAGInstrs *DAG, const SIInstrInfo *TII)
: IGLPStrategy(DAG, TII) {
IsBottomUp = 1;
}
};
bool MFMASmallGemmOpt::applyIGLPStrategy(
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
AMDGPU::SchedulingPhase Phase) {
// Count the number of MFMA instructions.
unsigned MFMACount = 0;
for (const MachineInstr &I : *DAG)
if (TII->isMFMAorWMMA(I))
++MFMACount;
const unsigned PipelineSyncID = 0;
SchedGroup *SG = nullptr;
for (unsigned I = 0; I < MFMACount * 3; ++I) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS, 2, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
return true;
}
class MFMAExpInterleaveOpt final : public IGLPStrategy {
private:
// The count of TRANS SUs involved in the interleaved pipeline
static unsigned TransPipeCount;
// The count of MFMA SUs involved in the interleaved pipeline
static unsigned MFMAPipeCount;
// The count of Add SUs involved in the interleaved pipeline
static unsigned AddPipeCount;
// The number of transitive MFMA successors for each TRANS SU
static unsigned MFMAEnablement;
// The number of transitive TRANS predecessors for each MFMA SU
static unsigned ExpRequirement;
// The count of independent "chains" of MFMA instructions in the pipeline
static unsigned MFMAChains;
// The length of each independent "chain" of MFMA instructions
static unsigned MFMAChainLength;
// Whether or not the pipeline has V_CVT instructions
static bool HasCvt;
// Whether or not there are instructions between the TRANS instruction and
// V_CVT
static bool HasChainBetweenCvt;
// The first occuring DS_READ which feeds an MFMA chain
static std::optional<unsigned> FirstPipeDSR;
// The MFMAPipe SUs with no MFMA predecessors
SmallVector<SUnit *, 4> MFMAChainSeeds;
// Compute the heuristics for the pipeline, returning whether or not the DAG
// is well formatted for the mutation
bool analyzeDAG(const SIInstrInfo *TII);
/// Whether or not the instruction is a transitive predecessor of an MFMA
/// instruction
class IsPipeExp final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
auto DAG = SyncPipe[0].DAG;
if (Cache->empty()) {
auto I = DAG->SUnits.rbegin();
auto E = DAG->SUnits.rend();
for (; I != E; I++) {
if (TII->isMFMAorWMMA(*I->getInstr()))
Cache->push_back(&*I);
}
if (Cache->empty())
return false;
}
auto Reaches = (std::any_of(
Cache->begin(), Cache->end(), [&SU, &DAG](SUnit *TargetSU) {
return DAG->IsReachable(TargetSU, const_cast<SUnit *>(SU));
}));
return Reaches;
}
IsPipeExp(const SIInstrInfo *TII, unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
/// Whether or not the instruction is a transitive predecessor of the
/// \p Number th MFMA of the MFMAs occuring after a TRANS instruction
class EnablesNthMFMA final : public InstructionRule {
private:
unsigned Number = 1;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
bool FoundTrans = false;
unsigned Counter = 1;
auto DAG = SyncPipe[0].DAG;
if (Cache->empty()) {
SmallVector<SUnit *, 8> Worklist;
auto I = DAG->SUnits.begin();
auto E = DAG->SUnits.end();
for (; I != E; I++) {
if (FoundTrans && TII->isMFMAorWMMA(*I->getInstr())) {
if (Counter == Number) {
Cache->push_back(&*I);
break;
}
++Counter;
}
if (!FoundTrans && TII->isTRANS(I->getInstr()->getOpcode()))
FoundTrans = true;
}
if (Cache->empty())
return false;
}
return DAG->IsReachable((*Cache)[0], const_cast<SUnit *>(SU));
}
EnablesNthMFMA(unsigned Number, const SIInstrInfo *TII, unsigned SGID,
bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Number(Number) {}
};
/// Whether or not the instruction enables the exact MFMA that is the \p
/// Number th MFMA in the chain starting with \p ChainSeed
class EnablesNthMFMAInChain final : public InstructionRule {
private:
unsigned Number = 1;
SUnit *ChainSeed;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
auto DAG = SyncPipe[0].DAG;
if (!SU || !TII->isMFMAorWMMA(*ChainSeed->getInstr()))
return false;
if (Cache->empty()) {
auto TempSU = ChainSeed;
auto Depth = Number;
while (Depth > 0) {
--Depth;
bool Found = false;
for (auto &Succ : TempSU->Succs) {
if (TII->isMFMAorWMMA(*Succ.getSUnit()->getInstr())) {
TempSU = Succ.getSUnit();
Found = true;
break;
}
}
if (!Found)
return false;
}
Cache->push_back(TempSU);
}
// If we failed to find the instruction to be placed into the cache, we
// would have already exited.
assert(!Cache->empty());
return DAG->IsReachable((*Cache)[0], const_cast<SUnit *>(SU));
}
EnablesNthMFMAInChain(unsigned Number, SUnit *ChainSeed,
const SIInstrInfo *TII, unsigned SGID,
bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Number(Number),
ChainSeed(ChainSeed) {}
};
/// Whether or not the instruction has less than \p Size immediate successors.
/// If \p HasIntermediary is true, this tests also whether all successors of
/// the SUnit have less than \p Size successors.
class LessThanNSuccs final : public InstructionRule {
private:
unsigned Size = 1;
bool HasIntermediary = false;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
if (!SyncPipe.size())
return false;
auto SuccSize = std::count_if(
SU->Succs.begin(), SU->Succs.end(),
[](const SDep &Succ) { return Succ.getKind() == SDep::Data; });
if (SuccSize >= Size)
return false;
if (HasIntermediary) {
for (auto Succ : SU->Succs) {
auto SuccSize = std::count_if(
Succ.getSUnit()->Succs.begin(), Succ.getSUnit()->Succs.end(),
[](const SDep &SuccSucc) {
return SuccSucc.getKind() == SDep::Data;
});
if (SuccSize >= Size)
return false;
}
}
return true;
}
LessThanNSuccs(unsigned Size, const SIInstrInfo *TII, unsigned SGID,
bool HasIntermediary = false, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Size(Size),
HasIntermediary(HasIntermediary) {}
};
/// Whether or not the instruction has greater than or equal to \p Size
/// immediate successors. If \p HasIntermediary is true, this tests also
/// whether all successors of the SUnit have greater than or equal to \p Size
/// successors.
class GreaterThanOrEqualToNSuccs final : public InstructionRule {
private:
unsigned Size = 1;
bool HasIntermediary = false;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
if (!SyncPipe.size())
return false;
auto SuccSize = std::count_if(
SU->Succs.begin(), SU->Succs.end(),
[](const SDep &Succ) { return Succ.getKind() == SDep::Data; });
if (SuccSize >= Size)
return true;
if (HasIntermediary) {
for (auto Succ : SU->Succs) {
auto SuccSize = std::count_if(
Succ.getSUnit()->Succs.begin(), Succ.getSUnit()->Succs.end(),
[](const SDep &SuccSucc) {
return SuccSucc.getKind() == SDep::Data;
});
if (SuccSize >= Size)
return true;
}
}
return false;
}
GreaterThanOrEqualToNSuccs(unsigned Size, const SIInstrInfo *TII,
unsigned SGID, bool HasIntermediary = false,
bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Size(Size),
HasIntermediary(HasIntermediary) {}
};
// Whether or not the instruction is a relevant V_CVT instruction.
class IsCvt final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
auto Opc = SU->getInstr()->getOpcode();
return Opc == AMDGPU::V_CVT_F16_F32_e32 ||
Opc == AMDGPU::V_CVT_I32_F32_e32;
}
IsCvt(const SIInstrInfo *TII, unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
// Whether or not the instruction is FMA_F32.
class IsFMA final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
return SU->getInstr()->getOpcode() == AMDGPU::V_FMA_F32_e64 ||
SU->getInstr()->getOpcode() == AMDGPU::V_PK_FMA_F32;
}
IsFMA(const SIInstrInfo *TII, unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
// Whether or not the instruction is a V_ADD_F32 instruction.
class IsPipeAdd final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
return SU->getInstr()->getOpcode() == AMDGPU::V_ADD_F32_e32;
}
IsPipeAdd(const SIInstrInfo *TII, unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
/// Whether or not the instruction is an immediate RAW successor
/// of the SchedGroup \p Distance steps before.
class IsSuccOfPrevNthGroup final : public InstructionRule {
private:
unsigned Distance = 1;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
SchedGroup *OtherGroup = nullptr;
if (!SyncPipe.size())
return false;
for (auto &PipeSG : SyncPipe) {
if ((unsigned)PipeSG.getSGID() == SGID - Distance)
OtherGroup = &PipeSG;
}
if (!OtherGroup)
return false;
if (!OtherGroup->Collection.size())
return true;
for (auto &OtherEle : OtherGroup->Collection) {
for (auto &Succ : OtherEle->Succs) {
if (Succ.getSUnit() == SU && Succ.getKind() == SDep::Data)
return true;
}
}
return false;
}
IsSuccOfPrevNthGroup(unsigned Distance, const SIInstrInfo *TII,
unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Distance(Distance) {}
};
/// Whether or not the instruction is a transitive successor of any
/// instruction the the SchedGroup \p Distance steps before.
class IsReachableFromPrevNthGroup final : public InstructionRule {
private:
unsigned Distance = 1;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
SchedGroup *OtherGroup = nullptr;
if (!SyncPipe.size())
return false;
for (auto &PipeSG : SyncPipe) {
if ((unsigned)PipeSG.getSGID() == SGID - Distance)
OtherGroup = &PipeSG;
}
if (!OtherGroup)
return false;
if (!OtherGroup->Collection.size())
return true;
auto DAG = SyncPipe[0].DAG;
for (auto &OtherEle : OtherGroup->Collection)
if (DAG->IsReachable(const_cast<SUnit *>(SU), OtherEle))
return true;
return false;
}
IsReachableFromPrevNthGroup(unsigned Distance, const SIInstrInfo *TII,
unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Distance(Distance) {}
};
/// Whether or not the instruction occurs after the SU with NodeNUm \p Number
class OccursAtOrAfterNode final : public InstructionRule {
private:
unsigned Number = 1;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
return SU->NodeNum >= Number;
}
OccursAtOrAfterNode(unsigned Number, const SIInstrInfo *TII, unsigned SGID,
bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Number(Number) {}
};
/// Whether or not the SU is exactly the \p Number th MFMA in the chain
/// starting with \p ChainSeed
class IsExactMFMA final : public InstructionRule {
private:
unsigned Number = 1;
SUnit *ChainSeed;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
if (!SU || !TII->isMFMAorWMMA(*ChainSeed->getInstr()))
return false;
if (Cache->empty()) {
auto TempSU = ChainSeed;
auto Depth = Number;
while (Depth > 0) {
--Depth;
bool Found = false;
for (auto &Succ : TempSU->Succs) {
if (TII->isMFMAorWMMA(*Succ.getSUnit()->getInstr())) {
TempSU = Succ.getSUnit();
Found = true;
break;
}
}
if (!Found) {
return false;
}
}
Cache->push_back(TempSU);
}
// If we failed to find the instruction to be placed into the cache, we
// would have already exited.
assert(!Cache->empty());
return (*Cache)[0] == SU;
}
IsExactMFMA(unsigned Number, SUnit *ChainSeed, const SIInstrInfo *TII,
unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Number(Number),
ChainSeed(ChainSeed) {}
};
// Whether the instruction occurs after the first TRANS instruction. This
// implies the instruction can not be a predecessor of the first TRANS
// insruction
class OccursAfterExp final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
SmallVector<SUnit *, 12> Worklist;
auto DAG = SyncPipe[0].DAG;
if (Cache->empty()) {
for (auto &SU : DAG->SUnits)
if (TII->isTRANS(SU.getInstr()->getOpcode())) {
Cache->push_back(&SU);
break;
}
if (Cache->empty())
return false;
}
return SU->NodeNum > (*Cache)[0]->NodeNum;
}
OccursAfterExp(const SIInstrInfo *TII, unsigned SGID,
bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
public:
bool applyIGLPStrategy(
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
AMDGPU::SchedulingPhase Phase) override;
bool shouldApplyStrategy(ScheduleDAGInstrs *DAG,
AMDGPU::SchedulingPhase Phase) override;
MFMAExpInterleaveOpt(ScheduleDAGInstrs *DAG, const SIInstrInfo *TII)
: IGLPStrategy(DAG, TII) {
IsBottomUp = 0;
}
};
unsigned MFMAExpInterleaveOpt::TransPipeCount = 0;
unsigned MFMAExpInterleaveOpt::MFMAPipeCount = 0;
unsigned MFMAExpInterleaveOpt::AddPipeCount = 0;
unsigned MFMAExpInterleaveOpt::MFMAEnablement = 0;
unsigned MFMAExpInterleaveOpt::ExpRequirement = 0;
unsigned MFMAExpInterleaveOpt::MFMAChains = 0;
unsigned MFMAExpInterleaveOpt::MFMAChainLength = 0;
bool MFMAExpInterleaveOpt::HasCvt = false;
bool MFMAExpInterleaveOpt::HasChainBetweenCvt = false;
std::optional<unsigned> MFMAExpInterleaveOpt::FirstPipeDSR = std::nullopt;
bool MFMAExpInterleaveOpt::analyzeDAG(const SIInstrInfo *TII) {
SmallVector<SUnit *, 10> ExpPipeCands;
SmallVector<SUnit *, 10> MFMAPipeCands;
SmallVector<SUnit *, 10> MFMAPipeSUs;
SmallVector<SUnit *, 10> PackSUs;
SmallVector<SUnit *, 10> CvtSUs;
auto isBitPack = [](unsigned Opc) {
return Opc == AMDGPU::V_PACK_B32_F16_e64 || Opc == AMDGPU::V_PERM_B32_e64;
};
auto isCvt = [](unsigned Opc) {
return Opc == AMDGPU::V_CVT_F16_F32_e32 || Opc == AMDGPU::V_CVT_I32_F32_e32;
};
auto isAdd = [](unsigned Opc) { return Opc == AMDGPU::V_ADD_F32_e32; };
AddPipeCount = 0;
for (SUnit &SU : DAG->SUnits) {
auto Opc = SU.getInstr()->getOpcode();
if (TII->isTRANS(Opc)) {
// Avoid counting a potential bonus V_EXP which all the MFMA depend on
if (SU.Succs.size() >= 7)
continue;
for (auto &Succ : SU.Succs) {
if (Succ.getSUnit()->Succs.size() >= 7)
continue;
}
ExpPipeCands.push_back(&SU);
}
if (TII->isMFMAorWMMA(*SU.getInstr()))
MFMAPipeCands.push_back(&SU);
if (isBitPack(Opc))
PackSUs.push_back(&SU);
if (isCvt(Opc))
CvtSUs.push_back(&SU);
if (isAdd(Opc))
++AddPipeCount;
}
if (!(PackSUs.size() && MFMAPipeCands.size() && ExpPipeCands.size()))
return false;
TransPipeCount = 0;
std::optional<SUnit *> TempMFMA;
std::optional<SUnit *> TempExp;
// Count the number of EXPs that reach an MFMA
for (auto &PredSU : ExpPipeCands) {
for (auto &SuccSU : MFMAPipeCands) {
if (DAG->IsReachable(SuccSU, PredSU)) {
if (!TempExp) {
TempExp = PredSU;
TempMFMA = SuccSU;
}
MFMAPipeSUs.push_back(SuccSU);
++TransPipeCount;
break;
}
}
}
if (!(TempExp && TempMFMA))
return false;
HasChainBetweenCvt =
std::find_if((*TempExp)->Succs.begin(), (*TempExp)->Succs.end(),
[&isCvt](SDep &Succ) {
return isCvt(Succ.getSUnit()->getInstr()->getOpcode());
}) == (*TempExp)->Succs.end();
// Count the number of MFMAs that are reached by an EXP
for (auto &SuccSU : MFMAPipeCands) {
if (MFMAPipeSUs.size() &&
std::find_if(MFMAPipeSUs.begin(), MFMAPipeSUs.end(),
[&SuccSU](SUnit *PotentialMatch) {
return PotentialMatch->NodeNum == SuccSU->NodeNum;
}) != MFMAPipeSUs.end())
continue;
for (auto &PredSU : ExpPipeCands) {
if (DAG->IsReachable(SuccSU, PredSU)) {
MFMAPipeSUs.push_back(SuccSU);
break;
}
}
}
MFMAPipeCount = MFMAPipeSUs.size();
assert(TempExp && TempMFMA);
assert(MFMAPipeCount > 0);
std::optional<SUnit *> TempCvt;
for (auto &SuccSU : CvtSUs) {
if (DAG->IsReachable(SuccSU, *TempExp)) {
TempCvt = SuccSU;
break;
}
}
HasCvt = false;
if (TempCvt.has_value()) {
for (auto &SuccSU : MFMAPipeSUs) {
if (DAG->IsReachable(SuccSU, *TempCvt)) {
HasCvt = true;
break;
}
}
}
MFMAChains = 0;
for (auto &MFMAPipeSU : MFMAPipeSUs) {
if (MFMAChainSeeds.size() &&
std::find(MFMAChainSeeds.begin(), MFMAChainSeeds.end(), MFMAPipeSU) !=
MFMAChainSeeds.end())
continue;
if (!std::any_of(MFMAPipeSU->Preds.begin(), MFMAPipeSU->Preds.end(),
[&TII](SDep &Succ) {
return TII->isMFMAorWMMA(*Succ.getSUnit()->getInstr());
})) {
MFMAChainSeeds.push_back(MFMAPipeSU);
++MFMAChains;
}
}
if (!MFMAChains)
return false;
for (auto Pred : MFMAChainSeeds[0]->Preds) {
if (TII->isDS(Pred.getSUnit()->getInstr()->getOpcode()) &&
Pred.getSUnit()->getInstr()->mayLoad())
FirstPipeDSR = Pred.getSUnit()->NodeNum;
}
MFMAChainLength = MFMAPipeCount / MFMAChains;
// The number of bit pack operations that depend on a single V_EXP
unsigned PackSuccCount = std::count_if(
PackSUs.begin(), PackSUs.end(), [this, &TempExp](SUnit *VPack) {
return DAG->IsReachable(VPack, *TempExp);
});
// The number of bit pack operations an MFMA depends on
unsigned PackPredCount =
std::count_if((*TempMFMA)->Preds.begin(), (*TempMFMA)->Preds.end(),
[&isBitPack](SDep &Pred) {
auto Opc = Pred.getSUnit()->getInstr()->getOpcode();
return isBitPack(Opc);
});
auto PackPred =
std::find_if((*TempMFMA)->Preds.begin(), (*TempMFMA)->Preds.end(),
[&isBitPack](SDep &Pred) {
auto Opc = Pred.getSUnit()->getInstr()->getOpcode();
return isBitPack(Opc);
});
if (PackPred == (*TempMFMA)->Preds.end())
return false;
MFMAEnablement = 0;
ExpRequirement = 0;
// How many MFMAs depend on a single bit pack operation
MFMAEnablement =
std::count_if(PackPred->getSUnit()->Succs.begin(),
PackPred->getSUnit()->Succs.end(), [&TII](SDep &Succ) {
return TII->isMFMAorWMMA(*Succ.getSUnit()->getInstr());
});
// The number of MFMAs that depend on a single V_EXP
MFMAEnablement *= PackSuccCount;
// The number of V_EXPs required to resolve all dependencies for an MFMA
ExpRequirement =
std::count_if(ExpPipeCands.begin(), ExpPipeCands.end(),
[this, &PackPred](SUnit *ExpBase) {
return DAG->IsReachable(PackPred->getSUnit(), ExpBase);
});
ExpRequirement *= PackPredCount;
return true;
}
bool MFMAExpInterleaveOpt::shouldApplyStrategy(ScheduleDAGInstrs *DAG,
AMDGPU::SchedulingPhase Phase) {
const GCNSubtarget &ST = DAG->MF.getSubtarget<GCNSubtarget>();
const SIInstrInfo *TII = ST.getInstrInfo();
if (Phase != AMDGPU::SchedulingPhase::PostRA)
MFMAChainSeeds.clear();
if (Phase != AMDGPU::SchedulingPhase::PostRA && !analyzeDAG(TII))
return false;
return true;
}
bool MFMAExpInterleaveOpt::applyIGLPStrategy(
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
AMDGPU::SchedulingPhase Phase) {
bool IsSmallKernelType =
MFMAEnablement == 2 && ExpRequirement == 4 && TransPipeCount == 32;
bool IsLargeKernelType =
MFMAEnablement == 4 && ExpRequirement == 4 && TransPipeCount == 64;
if (!(IsSmallKernelType || IsLargeKernelType))
return false;
const GCNSubtarget &ST = DAG->MF.getSubtarget<GCNSubtarget>();
const SIInstrInfo *TII = ST.getInstrInfo();
unsigned PipelineSyncID = 0;
SchedGroup *SG = nullptr;
unsigned MFMAChain = 0;
unsigned PositionInChain = 0;
unsigned CurrMFMAForTransPosition = 0;
auto incrementTransPosition = [&MFMAChain, &PositionInChain,
&CurrMFMAForTransPosition]() {
CurrMFMAForTransPosition += MFMAEnablement;
PositionInChain = (CurrMFMAForTransPosition / MFMAChains);
MFMAChain = CurrMFMAForTransPosition % MFMAChains;
};
auto getNextTransPositionInChain = [&CurrMFMAForTransPosition]() {
auto TempMFMAForTrans = CurrMFMAForTransPosition + MFMAEnablement;
return (TempMFMAForTrans / MFMAChains);
};
auto getNextTransMFMAChain = [&CurrMFMAForTransPosition]() {
auto TempMFMAForTrans = CurrMFMAForTransPosition + MFMAEnablement;
return TempMFMAForTrans % MFMAChains;
};
unsigned CurrMFMAPosition = 0;
unsigned MFMAChainForMFMA = 0;
unsigned PositionInChainForMFMA = 0;
auto incrementMFMAPosition = [&CurrMFMAPosition, &MFMAChainForMFMA,
&PositionInChainForMFMA]() {
++CurrMFMAPosition;
MFMAChainForMFMA = CurrMFMAPosition % MFMAChains;
PositionInChainForMFMA = CurrMFMAPosition / MFMAChains;
};
bool IsPostRA = Phase == AMDGPU::SchedulingPhase::PostRA;
assert(IsPostRA || MFMAChainSeeds.size() == MFMAChains);
bool UsesFMA = IsSmallKernelType || !IsPostRA;
bool UsesDSRead = IsLargeKernelType && !IsPostRA && FirstPipeDSR;
bool UsesCvt = HasCvt && (IsSmallKernelType || !IsPostRA);
bool UsesVALU = IsSmallKernelType;
// PHASE 1: "Prefetch"
if (UsesFMA) {
// First Round FMA
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, ExpRequirement, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains) {
SG->addRule(std::make_shared<EnablesNthMFMAInChain>(
PositionInChain, MFMAChainSeeds[MFMAChain], TII, SG->getSGID(),
true));
} else
SG->addRule(
std::make_shared<EnablesNthMFMA>(1, TII, SG->getSGID(), true));
SG->addRule(std::make_shared<IsFMA>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
// Second Round FMA
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, ExpRequirement, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains) {
SG->addRule(std::make_shared<EnablesNthMFMAInChain>(
getNextTransPositionInChain(),
MFMAChainSeeds[getNextTransMFMAChain()], TII, SG->getSGID(), true));
} else
SG->addRule(std::make_shared<EnablesNthMFMA>(MFMAEnablement + 1, TII,
SG->getSGID(), true));
SG->addRule(std::make_shared<IsFMA>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
if (UsesDSRead) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_READ, 2, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<OccursAtOrAfterNode>(*FirstPipeDSR, TII,
SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// First Round EXP
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::TRANS, ExpRequirement, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains)
SG->addRule(std::make_shared<EnablesNthMFMAInChain>(
PositionInChain, MFMAChainSeeds[MFMAChain], TII, SG->getSGID(), true));
else
SG->addRule(std::make_shared<EnablesNthMFMA>(1, TII, SG->getSGID(), true));
SG->addRule(std::make_shared<IsPipeExp>(TII, SG->getSGID(), true));
SG->addRule(std::make_shared<LessThanNSuccs>(8, TII, SG->getSGID(),
HasChainBetweenCvt));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
incrementTransPosition();
// First Round CVT, Third Round FMA, Second Round EXP; interleaved
for (unsigned I = 0; I < ExpRequirement; I++) {
// First Round CVT
if (UsesCvt) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 1, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsCvt>(TII, SG->getSGID()));
if (HasChainBetweenCvt)
SG->addRule(std::make_shared<IsReachableFromPrevNthGroup>(
1 + (2 + UsesFMA) * I, TII, SG->getSGID()));
else
SG->addRule(std::make_shared<IsSuccOfPrevNthGroup>(
1 + (2 + UsesFMA) * I, TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// Third Round FMA
if (UsesFMA) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 1, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains) {
SG->addRule(std::make_shared<EnablesNthMFMAInChain>(
getNextTransPositionInChain(),
MFMAChainSeeds[getNextTransMFMAChain()], TII, SG->getSGID(), true));
} else
SG->addRule(std::make_shared<EnablesNthMFMA>(2 * MFMAEnablement + 1,
TII, SG->getSGID(), true));
SG->addRule(std::make_shared<IsFMA>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// Second Round EXP
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::TRANS, 1, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains)
SG->addRule(std::make_shared<EnablesNthMFMAInChain>(
PositionInChain, MFMAChainSeeds[MFMAChain], TII, SG->getSGID(),
true));
else
SG->addRule(std::make_shared<EnablesNthMFMA>(MFMAEnablement + 1, TII,
SG->getSGID(), true));
SG->addRule(std::make_shared<IsPipeExp>(TII, SG->getSGID(), true));
SG->addRule(std::make_shared<LessThanNSuccs>(8, TII, SG->getSGID(),
HasChainBetweenCvt));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// The "extra" EXP which enables all MFMA
// TODO: UsesExtraExp
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::TRANS, 1, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsPipeExp>(TII, SG->getSGID(), true));
SG->addRule(std::make_shared<GreaterThanOrEqualToNSuccs>(
8, TII, SG->getSGID(), HasChainBetweenCvt));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
// PHASE 2: Main Interleave Loop
// The number of MFMAs per iteration
unsigned MFMARatio =
MFMAEnablement > ExpRequirement ? MFMAEnablement / ExpRequirement : 1;
// The number of Exps per iteration
unsigned ExpRatio =
MFMAEnablement > ExpRequirement ? 1 : ExpRequirement / MFMAEnablement;
// The reamaining Exps
unsigned RemainingExp = TransPipeCount > (2 * ExpRequirement)
? TransPipeCount - (2 * ExpRequirement)
: 0;
unsigned ExpLoopCount = RemainingExp / ExpRatio;
// In loop MFMAs
unsigned MFMAInLoop = MFMAPipeCount > (MFMAEnablement * 2)
? MFMAPipeCount - (MFMAEnablement * 2)
: 0;
unsigned MFMALoopCount = MFMAInLoop / MFMARatio;
unsigned VALUOps =
AddPipeCount < MFMAPipeCount ? 1 : AddPipeCount / MFMAPipeCount;
unsigned LoopSize = std::min(ExpLoopCount, MFMALoopCount);
for (unsigned I = 0; I < LoopSize; I++) {
if (!(I * ExpRatio % ExpRequirement))
incrementTransPosition();
// Round N MFMA
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, MFMARatio, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains)
SG->addRule(std::make_shared<IsExactMFMA>(
PositionInChainForMFMA, MFMAChainSeeds[MFMAChainForMFMA], TII,
SG->getSGID(), true));
else
SG->addRule(std::make_shared<OccursAfterExp>(TII, SG->getSGID(), true));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
incrementMFMAPosition();
if (UsesVALU) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, VALUOps, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsPipeAdd>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
if (UsesDSRead && !(I % 4)) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_READ, 2, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<OccursAtOrAfterNode>(*FirstPipeDSR, TII,
SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// CVT, EXP, FMA Interleaving
for (unsigned J = 0; J < ExpRatio; J++) {
auto MFMAOffset = (1 + UsesVALU) * MFMARatio * (I + 1);
auto MaxMFMAOffset =
(1 + UsesVALU) * ExpRequirement * MFMARatio / ExpRatio;
// Round N + 1 CVT
if (UsesCvt) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 1, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsCvt>(TII, SG->getSGID()));
auto BaseDiff = (2 + UsesFMA) * (ExpRequirement - 1) + 1;
auto DSROffset = I / 4 + 1;
auto MaxDSROffset = MaxMFMAOffset / 4;
// TODO: UsesExtraExp
auto ExpOffset = I * ExpRatio + J >= ExpRequirement ? 0 : 1;
auto CurrentOffset = UsesDSRead * std::min(MaxDSROffset, DSROffset) +
std::min(MaxMFMAOffset, MFMAOffset) + BaseDiff +
ExpOffset;
if (HasChainBetweenCvt)
SG->addRule(std::make_shared<IsReachableFromPrevNthGroup>(
CurrentOffset, TII, SG->getSGID()));
else
SG->addRule(std::make_shared<IsSuccOfPrevNthGroup>(CurrentOffset, TII,
SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// Round N + 3 FMA
if (UsesFMA) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 1, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains)
SG->addRule(std::make_shared<EnablesNthMFMAInChain>(
getNextTransPositionInChain(),
MFMAChainSeeds[getNextTransMFMAChain()], TII, SG->getSGID(),
true));
else
SG->addRule(std::make_shared<EnablesNthMFMA>(
(((I * ExpRatio + J) / ExpRequirement) + 3) * MFMAEnablement + 1,
TII, SG->getSGID(), true));
SG->addRule(std::make_shared<IsFMA>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// Round N + 2 Exp
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::TRANS, 1, PipelineSyncID, DAG, TII);
if (!IsPostRA && MFMAChains)
SG->addRule(std::make_shared<EnablesNthMFMAInChain>(
PositionInChain, MFMAChainSeeds[MFMAChain], TII, SG->getSGID(),
true));
else
SG->addRule(std::make_shared<EnablesNthMFMA>(
(((I * ExpRatio + J) / ExpRequirement) + 2) * MFMAEnablement + 1,
TII, SG->getSGID(), true));
SG->addRule(std::make_shared<IsPipeExp>(TII, SG->getSGID(), true));
SG->addRule(std::make_shared<LessThanNSuccs>(8, TII, SG->getSGID(),
HasChainBetweenCvt));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
}
// PHASE 3: Remaining MFMAs
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, MFMAEnablement * 2, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<OccursAfterExp>(TII, SG->getSGID(), true));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
return true;
}
class MFMASmallGemmSingleWaveOpt final : public IGLPStrategy {
private:
// Whether the DS_READ is a predecessor of first four MFMA in region
class EnablesInitialMFMA final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
if (!SyncPipe.size())
return false;
int MFMAsFound = 0;
if (!Cache->size()) {
for (auto &Elt : SyncPipe[0].DAG->SUnits) {
if (TII->isMFMAorWMMA(*Elt.getInstr())) {
++MFMAsFound;
if (MFMAsFound > 4)
break;
Cache->push_back(&Elt);
}
}
}
assert(Cache->size());
auto DAG = SyncPipe[0].DAG;
for (auto &Elt : *Cache) {
if (DAG->IsReachable(Elt, const_cast<SUnit *>(SU)))
return true;
}
return false;
}
EnablesInitialMFMA(const SIInstrInfo *TII, unsigned SGID,
bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
// Whether the MI is a V_PERM and is a predecessor of a common DS_WRITE
class IsPermForDSW final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
auto MI = SU->getInstr();
if (MI->getOpcode() != AMDGPU::V_PERM_B32_e64)
return false;
bool FitsInGroup = false;
// Does the VALU have a DS_WRITE successor
if (!Collection.size()) {
for (auto &Succ : SU->Succs) {
SUnit *SuccUnit = Succ.getSUnit();
if (TII->isDS(*SuccUnit->getInstr()) &&
SuccUnit->getInstr()->mayStore()) {
Cache->push_back(SuccUnit);
FitsInGroup = true;
}
}
return FitsInGroup;
}
assert(Cache->size());
// Does the VALU have a DS_WRITE successor that is the same as other
// VALU already in the group. The V_PERMs will all share 1 DS_W succ
return llvm::any_of(*Cache, [&SU](SUnit *Elt) {
return llvm::any_of(SU->Succs, [&Elt](const SDep &ThisSucc) {
return ThisSucc.getSUnit() == Elt;
});
});
}
IsPermForDSW(const SIInstrInfo *TII, unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
// Whether the SU is a successor of any element in previous SchedGroup
class IsSuccOfPrevGroup final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
SchedGroup *OtherGroup = nullptr;
for (auto &PipeSG : SyncPipe) {
if ((unsigned)PipeSG.getSGID() == SGID - 1) {
OtherGroup = &PipeSG;
}
}
if (!OtherGroup)
return false;
if (!OtherGroup->Collection.size())
return true;
// Does the previous VALU have this DS_Write as a successor
return (std::any_of(OtherGroup->Collection.begin(),
OtherGroup->Collection.end(), [&SU](SUnit *Elt) {
return std::any_of(Elt->Succs.begin(),
Elt->Succs.end(),
[&SU](SDep &Succ) {
return Succ.getSUnit() == SU;
});
}));
}
IsSuccOfPrevGroup(const SIInstrInfo *TII, unsigned SGID,
bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
// Whether the combined load width of group is 128 bits
class VMEMSize final : public InstructionRule {
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
auto MI = SU->getInstr();
if (MI->getOpcode() == TargetOpcode::BUNDLE)
return false;
if (!Collection.size())
return true;
int NumBits = 0;
auto TRI = TII->getRegisterInfo();
auto &MRI = MI->getParent()->getParent()->getRegInfo();
for (auto &Elt : Collection) {
auto Op = Elt->getInstr()->getOperand(0);
auto Size =
TRI.getRegSizeInBits(*TRI.getRegClassForOperandReg(MRI, Op));
NumBits += Size;
}
if (NumBits < 128) {
assert(TII->isVMEM(*MI) && MI->mayLoad());
if (NumBits + TRI.getRegSizeInBits(*TRI.getRegClassForOperandReg(
MRI, MI->getOperand(0))) <=
128)
return true;
}
return false;
}
VMEMSize(const SIInstrInfo *TII, unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache) {}
};
/// Whether the SU shares a V_PERM predecessor with any SU in the SchedGroup
/// that is \p Distance steps away
class SharesPredWithPrevNthGroup final : public InstructionRule {
private:
unsigned Distance = 1;
public:
bool apply(const SUnit *SU, const ArrayRef<SUnit *> Collection,
SmallVectorImpl<SchedGroup> &SyncPipe) override {
SchedGroup *OtherGroup = nullptr;
if (!SyncPipe.size())
return false;
if (!Cache->size()) {
for (auto &PipeSG : SyncPipe) {
if ((unsigned)PipeSG.getSGID() == SGID - Distance) {
OtherGroup = &PipeSG;
}
}
if (!OtherGroup)
return false;
if (!OtherGroup->Collection.size())
return true;
for (auto &OtherEle : OtherGroup->Collection) {
for (auto &Pred : OtherEle->Preds) {
if (Pred.getSUnit()->getInstr()->getOpcode() ==
AMDGPU::V_PERM_B32_e64)
Cache->push_back(Pred.getSUnit());
}
}
// If the other group has no PERM preds, then this group won't share any
if (!Cache->size())
return false;
}
auto DAG = SyncPipe[0].DAG;
// Does the previous DS_WRITE share a V_PERM predecessor with this
// VMEM_READ
return llvm::any_of(*Cache, [&SU, &DAG](SUnit *Elt) {
return DAG->IsReachable(const_cast<SUnit *>(SU), Elt);
});
}
SharesPredWithPrevNthGroup(unsigned Distance, const SIInstrInfo *TII,
unsigned SGID, bool NeedsCache = false)
: InstructionRule(TII, SGID, NeedsCache), Distance(Distance) {}
};
public:
bool applyIGLPStrategy(
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
AMDGPU::SchedulingPhase Phase) override;
bool shouldApplyStrategy(ScheduleDAGInstrs *DAG,
AMDGPU::SchedulingPhase Phase) override {
return true;
}
MFMASmallGemmSingleWaveOpt(ScheduleDAGInstrs *DAG, const SIInstrInfo *TII)
: IGLPStrategy(DAG, TII) {
IsBottomUp = 0;
}
};
static unsigned DSWCount = 0;
static unsigned DSWWithPermCount = 0;
static unsigned DSWWithSharedVMEMCount = 0;
bool MFMASmallGemmSingleWaveOpt::applyIGLPStrategy(
DenseMap<int, SUnitsToCandidateSGsMap> &SyncedInstrs,
DenseMap<int, SmallVector<SchedGroup, 4>> &SyncedSchedGroups,
AMDGPU::SchedulingPhase Phase) {
unsigned MFMACount = 0;
unsigned DSRCount = 0;
bool IsInitial = Phase == AMDGPU::SchedulingPhase::Initial;
assert((!IsInitial || (DSWCount == 0 && DSWWithPermCount == 0 &&
DSWWithSharedVMEMCount == 0)) &&
"DSWCounters should be zero in pre-RA scheduling!");
SmallVector<SUnit *, 6> DSWithPerms;
for (auto &SU : DAG->SUnits) {
auto I = SU.getInstr();
if (TII->isMFMAorWMMA(*I))
++MFMACount;
else if (TII->isDS(*I)) {
if (I->mayLoad())
++DSRCount;
else if (I->mayStore() && IsInitial) {
++DSWCount;
for (auto Pred : SU.Preds) {
if (Pred.getSUnit()->getInstr()->getOpcode() ==
AMDGPU::V_PERM_B32_e64) {
DSWithPerms.push_back(&SU);
break;
}
}
}
}
}
if (IsInitial) {
DSWWithPermCount = DSWithPerms.size();
auto I = DSWithPerms.begin();
auto E = DSWithPerms.end();
// Get the count of DS_WRITES with V_PERM predecessors which
// have loop carried dependencies (WAR) on the same VMEM_READs.
// We consider partial overlap as a miss -- in other words,
// for a given DS_W, we only consider another DS_W as matching
// if there is a corresponding (in terms of the VMEM_R it uses) V_PERM pred
// for every V_PERM pred of this DS_W.
DenseMap<MachineInstr *, SUnit *> VMEMLookup;
SmallVector<SUnit *, 6> Counted;
for (; I != E; I++) {
SUnit *Cand = nullptr;
bool MissedAny = false;
for (auto &Pred : (*I)->Preds) {
if (Pred.getSUnit()->getInstr()->getOpcode() != AMDGPU::V_PERM_B32_e64)
continue;
if (Cand && llvm::is_contained(Counted, Cand))
break;
for (auto &Succ : Pred.getSUnit()->Succs) {
auto MI = Succ.getSUnit()->getInstr();
if (!TII->isVMEM(*MI) || !MI->mayLoad())
continue;
if (MissedAny || !VMEMLookup.size()) {
MissedAny = true;
VMEMLookup[MI] = *I;
continue;
}
if (!VMEMLookup.contains(MI)) {
MissedAny = true;
VMEMLookup[MI] = *I;
continue;
}
Cand = VMEMLookup[MI];
if (llvm::is_contained(Counted, Cand)) {
MissedAny = true;
break;
}
}
}
if (!MissedAny && Cand) {
DSWWithSharedVMEMCount += 2;
Counted.push_back(Cand);
Counted.push_back(*I);
}
}
}
assert(DSWWithSharedVMEMCount <= DSWWithPermCount);
SchedGroup *SG;
unsigned PipelineSyncID = 0;
// For kernels with V_PERM, there are enough VALU to mix in between MFMAs
if (DSWWithPermCount) {
for (unsigned I = 0; I < MFMACount; I++) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 2, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
}
PipelineSyncID = 1;
// Phase 1: Break up DS_READ and MFMA clusters.
// First DS_READ to make ready initial MFMA, then interleave MFMA with DS_READ
// prefetch
// Make ready initial MFMA
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_READ, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<EnablesInitialMFMA>(TII, SG->getSGID(), true));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
// Interleave MFMA with DS_READ prefetch
for (unsigned I = 0; I < DSRCount - 4; ++I) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_READ, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// Phase 2a: Loop carried dependency with V_PERM
// Schedule VPerm & DS_WRITE as closely as possible to the VMEM_READ they
// depend on. Interleave MFMA to keep XDL unit busy throughout.
for (unsigned I = 0; I < DSWWithPermCount - DSWWithSharedVMEMCount; ++I) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsPermForDSW>(TII, SG->getSGID(), true));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_WRITE, 1, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsSuccOfPrevGroup>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VMEM_READ, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<SharesPredWithPrevNthGroup>(
1, TII, SG->getSGID(), true));
SG->addRule(std::make_shared<VMEMSize>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VMEM_READ, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<SharesPredWithPrevNthGroup>(
3, TII, SG->getSGID(), true));
SG->addRule(std::make_shared<VMEMSize>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// Phase 2b: Loop carried dependency without V_PERM
// Schedule DS_WRITE as closely as possible to the VMEM_READ they depend on.
// Interleave MFMA to keep XDL unit busy throughout.
for (unsigned I = 0; I < DSWCount - DSWWithPermCount; I++) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_WRITE, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VMEM_READ, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<VMEMSize>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
// Phase 2c: Loop carried dependency with V_PERM, VMEM_READs are
// ultimately used by two DS_WRITE
// Schedule VPerm & DS_WRITE as closely as possible to the VMEM_READ they
// depend on. Interleave MFMA to keep XDL unit busy throughout.
for (unsigned I = 0; I < DSWWithSharedVMEMCount; ++I) {
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsPermForDSW>(TII, SG->getSGID(), true));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_WRITE, 1, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsSuccOfPrevGroup>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VALU, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsPermForDSW>(TII, SG->getSGID(), true));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::DS_WRITE, 1, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<IsSuccOfPrevGroup>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VMEM_READ, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<SharesPredWithPrevNthGroup>(
2, TII, SG->getSGID(), true));
SG->addRule(std::make_shared<VMEMSize>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::VMEM_READ, 4, PipelineSyncID, DAG, TII);
SG->addRule(std::make_shared<SharesPredWithPrevNthGroup>(
4, TII, SG->getSGID(), true));
SG->addRule(std::make_shared<VMEMSize>(TII, SG->getSGID()));
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
SG = &SyncedSchedGroups[PipelineSyncID].emplace_back(
SchedGroupMask::MFMA, 1, PipelineSyncID, DAG, TII);
SG->initSchedGroup(SyncedInstrs[SG->getSyncID()]);
}
return true;
}
static std::unique_ptr<IGLPStrategy>
createIGLPStrategy(IGLPStrategyID ID, ScheduleDAGInstrs *DAG,
const SIInstrInfo *TII) {
switch (ID) {
case MFMASmallGemmOptID:
return std::make_unique<MFMASmallGemmOpt>(DAG, TII);
case MFMASmallGemmSingleWaveOptID:
return std::make_unique<MFMASmallGemmSingleWaveOpt>(DAG, TII);
case MFMAExpInterleave:
return std::make_unique<MFMAExpInterleaveOpt>(DAG, TII);
}
llvm_unreachable("Unknown IGLPStrategyID");
}
class IGroupLPDAGMutation : public ScheduleDAGMutation {
private:
const SIInstrInfo *TII;
ScheduleDAGMI *DAG;
// Organize lists of SchedGroups by their SyncID. SchedGroups /
// SCHED_GROUP_BARRIERs with different SyncIDs will have no edges added
// between then.
DenseMap<int, SmallVector<SchedGroup, 4>> SyncedSchedGroups;
// Used to track instructions that can be mapped to multiple sched groups
DenseMap<int, SUnitsToCandidateSGsMap> SyncedInstrs;
// Add DAG edges that enforce SCHED_BARRIER ordering.
void addSchedBarrierEdges(SUnit &SU);
// Use a SCHED_BARRIER's mask to identify instruction SchedGroups that should
// not be reordered accross the SCHED_BARRIER. This is used for the base
// SCHED_BARRIER, and not SCHED_GROUP_BARRIER. The difference is that
// SCHED_BARRIER will always block all instructions that can be classified
// into a particular SchedClass, whereas SCHED_GROUP_BARRIER has a fixed size
// and may only synchronize with some SchedGroups. Returns the inverse of
// Mask. SCHED_BARRIER's mask describes which instruction types should be
// allowed to be scheduled across it. Invert the mask to get the
// SchedGroupMask of instructions that should be barred.
SchedGroupMask invertSchedBarrierMask(SchedGroupMask Mask) const;
// Create SchedGroups for a SCHED_GROUP_BARRIER.
void initSchedGroupBarrierPipelineStage(
std::vector<SUnit>::reverse_iterator RIter);
bool initIGLPOpt(SUnit &SU);
public:
void apply(ScheduleDAGInstrs *DAGInstrs) override;
// The order in which the PipelineSolver should process the candidate
// SchedGroup for a PipelineInstr. BOTTOM_UP will try to add SUs to the last
// created SchedGroup first, and will consider that as the ultimate
// predecessor group when linking. TOP_DOWN instead links and processes the
// first created SchedGroup first.
bool IsBottomUp = 1;
// The scheduling phase this application of IGLP corresponds with.
AMDGPU::SchedulingPhase Phase = AMDGPU::SchedulingPhase::Initial;
IGroupLPDAGMutation() = default;
IGroupLPDAGMutation(AMDGPU::SchedulingPhase Phase) : Phase(Phase) {}
};
unsigned SchedGroup::NumSchedGroups = 0;
bool SchedGroup::tryAddEdge(SUnit *A, SUnit *B) {
if (A != B && DAG->canAddEdge(B, A)) {
DAG->addEdge(B, SDep(A, SDep::Artificial));
return true;
}
return false;
}
bool SchedGroup::canAddMI(const MachineInstr &MI) const {
bool Result = false;
if (MI.isMetaInstruction())
Result = false;
else if (((SGMask & SchedGroupMask::ALU) != SchedGroupMask::NONE) &&
(TII->isVALU(MI) || TII->isMFMAorWMMA(MI) || TII->isSALU(MI) ||
TII->isTRANS(MI)))
Result = true;
else if (((SGMask & SchedGroupMask::VALU) != SchedGroupMask::NONE) &&
TII->isVALU(MI) && !TII->isMFMAorWMMA(MI) && !TII->isTRANS(MI))
Result = true;
else if (((SGMask & SchedGroupMask::SALU) != SchedGroupMask::NONE) &&
TII->isSALU(MI))
Result = true;
else if (((SGMask & SchedGroupMask::MFMA) != SchedGroupMask::NONE) &&
TII->isMFMAorWMMA(MI))
Result = true;
else if (((SGMask & SchedGroupMask::VMEM) != SchedGroupMask::NONE) &&
(TII->isVMEM(MI) || (TII->isFLAT(MI) && !TII->isDS(MI))))
Result = true;
else if (((SGMask & SchedGroupMask::VMEM_READ) != SchedGroupMask::NONE) &&
MI.mayLoad() &&
(TII->isVMEM(MI) || (TII->isFLAT(MI) && !TII->isDS(MI))))
Result = true;
else if (((SGMask & SchedGroupMask::VMEM_WRITE) != SchedGroupMask::NONE) &&
MI.mayStore() &&
(TII->isVMEM(MI) || (TII->isFLAT(MI) && !TII->isDS(MI))))
Result = true;
else if (((SGMask & SchedGroupMask::DS) != SchedGroupMask::NONE) &&
TII->isDS(MI))
Result = true;
else if (((SGMask & SchedGroupMask::DS_READ) != SchedGroupMask::NONE) &&
MI.mayLoad() && TII->isDS(MI))
Result = true;
else if (((SGMask & SchedGroupMask::DS_WRITE) != SchedGroupMask::NONE) &&
MI.mayStore() && TII->isDS(MI))
Result = true;
else if (((SGMask & SchedGroupMask::TRANS) != SchedGroupMask::NONE) &&
TII->isTRANS(MI))
Result = true;
LLVM_DEBUG(
dbgs() << "For SchedGroup with mask " << format_hex((int)SGMask, 10, true)
<< (Result ? " could classify " : " unable to classify ") << MI);
return Result;
}
int SchedGroup::link(SUnit &SU, bool MakePred,
std::vector<std::pair<SUnit *, SUnit *>> &AddedEdges) {
int MissedEdges = 0;
for (auto *A : Collection) {
SUnit *B = &SU;
if (A == B || A->getInstr()->getOpcode() == AMDGPU::SCHED_GROUP_BARRIER)
continue;
if (MakePred)
std::swap(A, B);
if (DAG->IsReachable(B, A))
continue;
// tryAddEdge returns false if there is a dependency that makes adding
// the A->B edge impossible, otherwise it returns true;
bool Added = tryAddEdge(A, B);
if (Added)
AddedEdges.push_back(std::pair(A, B));
else
++MissedEdges;
}
return MissedEdges;
}
void SchedGroup::link(SUnit &SU, bool MakePred) {
for (auto *A : Collection) {
SUnit *B = &SU;
if (A->getInstr()->getOpcode() == AMDGPU::SCHED_GROUP_BARRIER)
continue;
if (MakePred)
std::swap(A, B);
tryAddEdge(A, B);
}
}
void SchedGroup::link(SUnit &SU,
function_ref<bool(const SUnit *A, const SUnit *B)> P) {
for (auto *A : Collection) {
SUnit *B = &SU;
if (P(A, B))
std::swap(A, B);
tryAddEdge(A, B);
}
}
void SchedGroup::link(SchedGroup &OtherGroup) {
for (auto *B : OtherGroup.Collection)
link(*B);
}
bool SchedGroup::canAddSU(SUnit &SU) const {
MachineInstr &MI = *SU.getInstr();
if (MI.getOpcode() != TargetOpcode::BUNDLE)
return canAddMI(MI);
// Special case for bundled MIs.
const MachineBasicBlock *MBB = MI.getParent();
MachineBasicBlock::instr_iterator B = MI.getIterator(), E = ++B;
while (E != MBB->end() && E->isBundledWithPred())
++E;
// Return true if all of the bundled MIs can be added to this group.
return std::all_of(B, E, [this](MachineInstr &MI) { return canAddMI(MI); });
}
void SchedGroup::initSchedGroup() {
for (auto &SU : DAG->SUnits) {
if (isFull())
break;
if (canAddSU(SU))
add(SU);
}
}
void SchedGroup::initSchedGroup(std::vector<SUnit>::reverse_iterator RIter,
SUnitsToCandidateSGsMap &SyncedInstrs) {
SUnit &InitSU = *RIter;
for (auto E = DAG->SUnits.rend(); RIter != E; ++RIter) {
auto &SU = *RIter;
if (isFull())
break;
if (canAddSU(SU))
SyncedInstrs[&SU].push_back(SGID);
}
add(InitSU);
assert(MaxSize);
(*MaxSize)++;
}
void SchedGroup::initSchedGroup(SUnitsToCandidateSGsMap &SyncedInstrs) {
auto I = DAG->SUnits.rbegin();
auto E = DAG->SUnits.rend();
for (; I != E; ++I) {
auto &SU = *I;
if (isFull())
break;
if (canAddSU(SU))
SyncedInstrs[&SU].push_back(SGID);
}
}
void IGroupLPDAGMutation::apply(ScheduleDAGInstrs *DAGInstrs) {
const TargetSchedModel *TSchedModel = DAGInstrs->getSchedModel();
if (!TSchedModel || DAGInstrs->SUnits.empty())
return;
LLVM_DEBUG(dbgs() << "Applying IGroupLPDAGMutation...\n");
const GCNSubtarget &ST = DAGInstrs->MF.getSubtarget<GCNSubtarget>();
TII = ST.getInstrInfo();
DAG = static_cast<ScheduleDAGMI *>(DAGInstrs);
SyncedSchedGroups.clear();
SyncedInstrs.clear();
bool FoundSB = false;
bool FoundIGLP = false;
bool ShouldApplyIGLP = false;
for (auto R = DAG->SUnits.rbegin(), E = DAG->SUnits.rend(); R != E; ++R) {
unsigned Opc = R->getInstr()->getOpcode();
// SCHED_[GROUP_]BARRIER and IGLP are mutually exclusive.
if (Opc == AMDGPU::SCHED_BARRIER) {
addSchedBarrierEdges(*R);
FoundSB = true;
} else if (Opc == AMDGPU::SCHED_GROUP_BARRIER) {
initSchedGroupBarrierPipelineStage(R);
FoundSB = true;
} else if (Opc == AMDGPU::IGLP_OPT) {
resetEdges(*R, DAG);
if (!FoundSB && !FoundIGLP) {
FoundIGLP = true;
ShouldApplyIGLP = initIGLPOpt(*R);
}
}
}
if (FoundSB || (FoundIGLP && ShouldApplyIGLP)) {
PipelineSolver PS(SyncedSchedGroups, SyncedInstrs, DAG, IsBottomUp);
// PipelineSolver performs the mutation by adding the edges it
// determined as the best
PS.solve();
return;
}
}
void IGroupLPDAGMutation::addSchedBarrierEdges(SUnit &SchedBarrier) {
MachineInstr &MI = *SchedBarrier.getInstr();
assert(MI.getOpcode() == AMDGPU::SCHED_BARRIER);
// Remove all existing edges from the SCHED_BARRIER that were added due to the
// instruction having side effects.
resetEdges(SchedBarrier, DAG);
LLVM_DEBUG(dbgs() << "Building SchedGroup for SchedBarrier with Mask: "
<< MI.getOperand(0).getImm() << "\n");
auto InvertedMask =
invertSchedBarrierMask((SchedGroupMask)MI.getOperand(0).getImm());
SchedGroup SG(InvertedMask, std::nullopt, DAG, TII);
SG.initSchedGroup();
// Preserve original instruction ordering relative to the SCHED_BARRIER.
SG.link(
SchedBarrier,
(function_ref<bool(const SUnit *A, const SUnit *B)>)[](
const SUnit *A, const SUnit *B) { return A->NodeNum > B->NodeNum; });
}
SchedGroupMask
IGroupLPDAGMutation::invertSchedBarrierMask(SchedGroupMask Mask) const {
// Invert mask and erase bits for types of instructions that are implied to be
// allowed past the SCHED_BARRIER.
SchedGroupMask InvertedMask = ~Mask;
// ALU implies VALU, SALU, MFMA, TRANS.
if ((InvertedMask & SchedGroupMask::ALU) == SchedGroupMask::NONE)
InvertedMask &= ~SchedGroupMask::VALU & ~SchedGroupMask::SALU &
~SchedGroupMask::MFMA & ~SchedGroupMask::TRANS;
// VALU, SALU, MFMA, TRANS implies ALU.
else if ((InvertedMask & SchedGroupMask::VALU) == SchedGroupMask::NONE ||
(InvertedMask & SchedGroupMask::SALU) == SchedGroupMask::NONE ||
(InvertedMask & SchedGroupMask::MFMA) == SchedGroupMask::NONE ||
(InvertedMask & SchedGroupMask::TRANS) == SchedGroupMask::NONE)
InvertedMask &= ~SchedGroupMask::ALU;
// VMEM implies VMEM_READ, VMEM_WRITE.
if ((InvertedMask & SchedGroupMask::VMEM) == SchedGroupMask::NONE)
InvertedMask &= ~SchedGroupMask::VMEM_READ & ~SchedGroupMask::VMEM_WRITE;
// VMEM_READ, VMEM_WRITE implies VMEM.
else if ((InvertedMask & SchedGroupMask::VMEM_READ) == SchedGroupMask::NONE ||
(InvertedMask & SchedGroupMask::VMEM_WRITE) == SchedGroupMask::NONE)
InvertedMask &= ~SchedGroupMask::VMEM;
// DS implies DS_READ, DS_WRITE.
if ((InvertedMask & SchedGroupMask::DS) == SchedGroupMask::NONE)
InvertedMask &= ~SchedGroupMask::DS_READ & ~SchedGroupMask::DS_WRITE;
// DS_READ, DS_WRITE implies DS.
else if ((InvertedMask & SchedGroupMask::DS_READ) == SchedGroupMask::NONE ||
(InvertedMask & SchedGroupMask::DS_WRITE) == SchedGroupMask::NONE)
InvertedMask &= ~SchedGroupMask::DS;
LLVM_DEBUG(dbgs() << "After Inverting, SchedGroup Mask: " << (int)InvertedMask
<< "\n");
return InvertedMask;
}
void IGroupLPDAGMutation::initSchedGroupBarrierPipelineStage(
std::vector<SUnit>::reverse_iterator RIter) {
// Remove all existing edges from the SCHED_GROUP_BARRIER that were added due
// to the instruction having side effects.
resetEdges(*RIter, DAG);
MachineInstr &SGB = *RIter->getInstr();
assert(SGB.getOpcode() == AMDGPU::SCHED_GROUP_BARRIER);
int32_t SGMask = SGB.getOperand(0).getImm();
int32_t Size = SGB.getOperand(1).getImm();
int32_t SyncID = SGB.getOperand(2).getImm();
auto &SG = SyncedSchedGroups[SyncID].emplace_back((SchedGroupMask)SGMask,
Size, SyncID, DAG, TII);
SG.initSchedGroup(RIter, SyncedInstrs[SG.getSyncID()]);
}
bool IGroupLPDAGMutation::initIGLPOpt(SUnit &SU) {
IGLPStrategyID StrategyID =
(IGLPStrategyID)SU.getInstr()->getOperand(0).getImm();
auto S = createIGLPStrategy(StrategyID, DAG, TII);
if (!S->shouldApplyStrategy(DAG, Phase))
return false;
IsBottomUp = S->IsBottomUp;
return S->applyIGLPStrategy(SyncedInstrs, SyncedSchedGroups, Phase);
}
} // namespace
namespace llvm {
/// \p Phase specifes whether or not this is a reentry into the
/// IGroupLPDAGMutation. Since there may be multiple scheduling passes on the
/// same scheduling region (e.g. pre and post-RA scheduling / multiple
/// scheduling "phases"), we can reenter this mutation framework more than once
/// for a given region.
std::unique_ptr<ScheduleDAGMutation>
createIGroupLPDAGMutation(AMDGPU::SchedulingPhase Phase) {
return std::make_unique<IGroupLPDAGMutation>(Phase);
}
} // end namespace llvm