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[AIE NFC] Postpipeliner cleanups and refactorings #253

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[AIE NFC] Postpipeliner cleanups and refactorings #253

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8baa1cf
[AIE] Pack NodeInfo in a class with additional information
Dec 10, 2024
03951f0
[AIE] Push Earliest with local resource contention
Dec 12, 2024
3cd1db1
[AIE] Specify maxii relative to MinII
Dec 12, 2024
37d1a95
[AIE] Compute MinEarliest, MaxEarliest and MinLatest
Dec 12, 2024
505d73f
[AIE] Don't print edges to ExitSU
Dec 12, 2024
11bc08e
[AIE] Maintain II in the pipeliner strategy
Dec 12, 2024
6636a0a
[AIE] Add conv2d-bf16 test with feasible register allocation
Dec 12, 2024
7f4c316
[AIE] Bail out if RecMII not met.
Dec 12, 2024
95dbddf
[AIE] Reject NStages=1 pipelines
Jan 14, 2025
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115 changes: 61 additions & 54 deletions llvm/lib/Target/AIE/AIEPostPipeliner.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -323,7 +323,7 @@ bool PostPipeliner::computeLoopCarriedParameters() {
}

// Save the static values for ease of reset
for (auto &N : Info) {
for (auto &N : Info.Nodes) {
N.StaticEarliest = N.Earliest;
N.StaticLatest = N.Latest;
}
Expand All @@ -343,24 +343,23 @@ int PostPipeliner::computeMinScheduleLength() const {
return MinLength;
}

void dumpGraph(int NInstr, const std::vector<NodeInfo> &Info,
ScheduleDAGInstrs *DAG) {
void dumpGraph(const ScheduleInfo &Info, ScheduleDAGInstrs *DAG) {
dbgs() << "digraph {\n";

for (int K = 0; K < NInstr; K++) {
for (int K = 0; K < Info.NInstr; K++) {
auto &SU = DAG->SUnits[K];
for (auto &Dep : SU.Succs) {
auto *Succ = Dep.getSUnit();
int S = Succ->NodeNum;
if (S % NInstr == K) {
if (S % Info.NInstr == K) {
continue;
}

dbgs() << "\tSU" << K << " -> "
<< "SU" << S;

if (S >= NInstr) {
dbgs() << "_" << S % NInstr;
if (S >= Info.NInstr) {
dbgs() << "_" << S % Info.NInstr;
}
if (Dep.getKind() == SDep::Data) {
dbgs() << " [color=red] ";
Expand Down Expand Up @@ -476,7 +475,7 @@ bool PostPipeliner::scheduleFirstIteration(PostPipelinerStrategy &Strategy) {
}

namespace {
void dumpEarliestChain(const std::vector<NodeInfo> &Info, int N) {
void dumpEarliestChain(const ScheduleInfo &Info, int N) {
auto Prev = Info[N].LastEarliestPusher;
if (Prev) {
dumpEarliestChain(Info, *Prev);
Expand Down Expand Up @@ -515,8 +514,7 @@ bool PostPipeliner::scheduleOtherIterations() {

class DefaultStrategy : public PostPipelinerStrategy {
public:
DefaultStrategy(ScheduleDAGMI &DAG, std::vector<NodeInfo> &Info,
int LatestBias)
DefaultStrategy(ScheduleDAGMI &DAG, ScheduleInfo &Info, int LatestBias)
: PostPipelinerStrategy(DAG, Info, LatestBias) {}
bool better(const SUnit &A, const SUnit &B) override {
return Info[A.NodeNum].Latest < Info[B.NodeNum].Latest;
Expand All @@ -525,6 +523,7 @@ class DefaultStrategy : public PostPipelinerStrategy {

class ConfigStrategy : public PostPipelinerStrategy {
bool TopDown = true;
bool Alternate = false;

public:
enum PriorityComponent {
Expand Down Expand Up @@ -552,6 +551,13 @@ class ConfigStrategy : public PostPipelinerStrategy {
}
return "Size - Illegal";
}
struct Configuration {
int ExtraStages = 0;
bool TopDown = true;
bool Alternate = false;
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Would be nice to document those fields, especially Alternate

int Runs = 0;
ArrayRef<PriorityComponent> Components;
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Why not own the list of components? Does that help a lot with memory usage?

};

private:
std::string Name;
Expand Down Expand Up @@ -597,6 +603,12 @@ class ConfigStrategy : public PostPipelinerStrategy {
return false;
}

int earliest(const SUnit &N) override { return Info[N.NodeNum].Earliest; }

int latest(const SUnit &N) override {
return Info[N.NodeNum].Latest + LatestBias;
}

void selected(const SUnit &N) override {
// Promote the critical path
NodeInfo *Pushed = &Info[N.NodeNum];
Expand Down Expand Up @@ -628,75 +640,71 @@ class ConfigStrategy : public PostPipelinerStrategy {
PredSiblingScheduled.insert(PDep.getSUnit()->NodeNum);
}
}
if (Alternate) {
TopDown = !TopDown;
}
}

public:
std::string name() override { return Name; }
ConfigStrategy(ScheduleDAGInstrs &DAG, std::vector<NodeInfo> &Info,
int Length, bool TopDown,
ConfigStrategy(ScheduleDAGInstrs &DAG, ScheduleInfo &Info, int Length,
bool TopDown, bool Alternate,
ArrayRef<PriorityComponent> Components)
: PostPipelinerStrategy(DAG, Info, Length), TopDown(TopDown) {
Name = "Config_" + std::to_string(Length) + "_" + std::to_string(TopDown);
: PostPipelinerStrategy(DAG, Info, Length), TopDown(TopDown),
Alternate(Alternate) {
Name = "Config_" + std::to_string(Length) + "_" + std::to_string(TopDown) +
"_" + std::to_string(Alternate);
for (auto Comp : Components) {
Name += "_" + getPriorityName(Comp);
Priority.emplace_back(Comp);
}
}
};

static const struct {
int ExtraStages;
bool TopDown;
bool Rerun;
ConfigStrategy::PriorityComponent Components[3];
} Strategies[] = {
static const ConfigStrategy::PriorityComponent
NodeNum[] = {ConfigStrategy::NodeNum},
Latest[] = {ConfigStrategy::Latest},
Critical[] = {ConfigStrategy::Critical},
CriticalLCDLatest[] = {ConfigStrategy::Critical, ConfigStrategy::LCDLatest};

static const ConfigStrategy::Configuration Strategies[] = {
// Loosely speaking, a lower value of the first parameter targets
// a lower stage count, which benefits code size.
// Rerurn is only useful for heuristics that use it, e.g. Critical
{1, true, false, {ConfigStrategy::NodeNum}},
{1, true, false, {ConfigStrategy::Latest}},
{1, true, true, {ConfigStrategy::Critical}},
{1, true, true, {ConfigStrategy::Critical, ConfigStrategy::LCDLatest}},
{0, false, true, {ConfigStrategy::Critical, ConfigStrategy::LCDLatest}},
{1, false, true, {ConfigStrategy::Critical, ConfigStrategy::LCDLatest}},
// Runs>1 is only useful for heuristics that use it, e.g. Critical
// {ExtraStages, TopDown, Alternate, Runs, Components}
{1, true, false, 1, NodeNum},
{1, true, false, 1, Latest},
{1, true, false, 2, Critical},
{1, true, false, 2, CriticalLCDLatest},
{0, false, false, 2, CriticalLCDLatest},
{1, false, false, 2, CriticalLCDLatest},
// This is pure bottom up
{1, false, false, {ConfigStrategy::NodeNum}},
{1, false, false, 1, NodeNum},
};

bool PostPipeliner::tryHeuristics() {
int MinLength = computeMinScheduleLength();

DEBUG_SUMMARY(dbgs() << "-- MinLength=" << MinLength << "\n");

int HeuristicIndex = 0;
for (auto &[ExtraStages, TopDown, Rerun, Components] : Strategies) {
for (const auto &Config : Strategies) {
if (Heuristic >= 0 && Heuristic != HeuristicIndex++) {
continue;
}
ConfigStrategy S(*DAG, Info, MinLength + ExtraStages * II, TopDown,
Components);
ConfigStrategy S(*DAG, Info, MinLength + Config.ExtraStages * II,
Config.TopDown, Config.Alternate, Config.Components);
resetSchedule(/*FullReset=*/true);
DEBUG_SUMMARY(dbgs() << "--- Strategy " << S.name() << "\n");
if (scheduleFirstIteration(S) && scheduleOtherIterations()) {
DEBUG_SUMMARY(dbgs() << " Strategy " << S.name() << " found II=" << II
for (int Run = 0; Run < Config.Runs; Run++) {
DEBUG_SUMMARY(dbgs() << "--- Strategy " << S.name() << " run=" << Run
<< "\n");
return true;
}

DEBUG_SUMMARY(dbgs() << " failed\n");
if (!Rerun) {
continue;
}

// Rerun with dynamic information retained
resetSchedule(/*FullReset=*/false);
DEBUG_SUMMARY(dbgs() << "--- Strategy " << S.name()
<< " with critical path");
if (scheduleFirstIteration(S) && scheduleOtherIterations()) {
DEBUG_SUMMARY(dbgs() << " found II=" << II << "\n");
return true;
if (scheduleFirstIteration(S) && scheduleOtherIterations()) {
DEBUG_SUMMARY(dbgs() << " Strategy " << S.name() << " run=" << Run
<< " found II=" << II << "\n");
return true;
}
resetSchedule(/*FullReset=*/false);
}
DEBUG_SUMMARY(dbgs() << " failed\n");
DEBUG_SUMMARY(dbgs() << " Strategy " << S.name() << " failed\n");
}
DEBUG_SUMMARY(dbgs() << "=== II=" << II << " Failed ===\n");
return false;
Expand All @@ -718,12 +726,11 @@ bool PostPipeliner::schedule(ScheduleDAGMI &TheDAG, int InitiationInterval) {
Depth = NCopies * II + HR.getPipelineDepth();
Scoreboard.reset(Depth);

Info.clear();
Info.resize(NTotalInstrs);
Info.init(NInstr, NCopies);

LLVM_DEBUG(for (int I = 0; I < NInstr;
I++) { dbgs() << I << " " << *DAG->SUnits[I].getInstr(); });
LLVM_DEBUG(dumpGraph(NInstr, Info, DAG));
LLVM_DEBUG(dumpGraph(Info, DAG));

computeLoopCarriedParameters();

Expand Down
22 changes: 18 additions & 4 deletions llvm/lib/Target/AIE/AIEPostPipeliner.h
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Original file line number Diff line number Diff line change
Expand Up @@ -90,14 +90,27 @@ class NodeInfo {
void reset(bool FullReset);
};

class ScheduleInfo {
public:
std::vector<NodeInfo> Nodes;
int NInstr;
void init(int NOrig, int NCopies) {
NInstr = NOrig;
Nodes.clear();
Nodes.resize(NInstr * NCopies);
}
NodeInfo &operator[](int N) { return Nodes[N]; }
const NodeInfo &operator[](int N) const { return Nodes[N]; }
};

class PostPipelinerStrategy {
protected:
ScheduleDAGInstrs &DAG;
std::vector<NodeInfo> &Info;
ScheduleInfo &Info;
int LatestBias = 0;

public:
PostPipelinerStrategy(ScheduleDAGInstrs &DAG, std::vector<NodeInfo> &Info,
PostPipelinerStrategy(ScheduleDAGInstrs &DAG, ScheduleInfo &Info,
int LatestBias)
: DAG(DAG), Info(Info), LatestBias(LatestBias) {};
virtual ~PostPipelinerStrategy() {};
Expand Down Expand Up @@ -139,9 +152,10 @@ class PostPipeliner {
int FirstUnscheduled = 0;
int LastUnscheduled = -1;

/// Holds the cycle of each SUnit. The following should hold:
/// Holds the schuling information for each instruction. The following
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schuling -> scheduling

/// should hold:
/// Cycle(N) mod II == Cycle(N % NInstr) mod II
std::vector<NodeInfo> Info;
ScheduleInfo Info;

// The scoreboard and its depth
ResourceScoreboard<FuncUnitWrapper> Scoreboard;
Expand Down