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-rw-r--r--llvm/include/llvm/MCA/HardwareUnits/LSUnit.h2
-rw-r--r--llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp104
-rw-r--r--llvm/tools/llvm-mca/Views/BottleneckAnalysis.h53
-rw-r--r--llvm/tools/llvm-mca/llvm-mca.cpp6
4 files changed, 93 insertions, 72 deletions
diff --git a/llvm/include/llvm/MCA/HardwareUnits/LSUnit.h b/llvm/include/llvm/MCA/HardwareUnits/LSUnit.h
index f2a5cf86ca4..ae9a49c6485 100644
--- a/llvm/include/llvm/MCA/HardwareUnits/LSUnit.h
+++ b/llvm/include/llvm/MCA/HardwareUnits/LSUnit.h
@@ -158,7 +158,7 @@ public:
}
void cycleEvent() {
- if (CriticalPredecessor.Cycles)
+ if (isWaiting() && CriticalPredecessor.Cycles)
CriticalPredecessor.Cycles--;
}
};
diff --git a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp
index c10e47d5165..8c825271e4f 100644
--- a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp
+++ b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp
@@ -143,114 +143,118 @@ void PressureTracker::handlePressureEvent(const HWPressureEvent &Event) {
}
#ifndef NDEBUG
-void DependencyGraph::dumpDependencyEdge(raw_ostream &OS, unsigned FromIID,
- const DependencyEdge &DE,
+void DependencyGraph::dumpDependencyEdge(raw_ostream &OS,
+ const DependencyEdge &DepEdge,
MCInstPrinter &MCIP) const {
- bool LoopCarried = FromIID >= DE.IID;
- OS << " FROM: " << FromIID << " TO: " << DE.IID
- << (LoopCarried ? " (loop carried)" : " ");
- if (DE.Type == DT_REGISTER) {
+ unsigned FromIID = DepEdge.FromIID;
+ unsigned ToIID = DepEdge.ToIID;
+ assert(FromIID < ToIID && "Graph should be acyclic!");
+
+ const DependencyEdge::Dependency &DE = DepEdge.Dep;
+ assert(DE.Type != DependencyEdge::DT_INVALID && "Unexpected invalid edge!");
+
+ OS << " FROM: " << FromIID << " TO: " << ToIID << " ";
+ if (DE.Type == DependencyEdge::DT_REGISTER) {
OS << " - REGISTER: ";
MCIP.printRegName(OS, DE.ResourceOrRegID);
- } else if (DE.Type == DT_MEMORY) {
+ } else if (DE.Type == DependencyEdge::DT_MEMORY) {
OS << " - MEMORY";
} else {
- assert(DE.Type == DT_RESOURCE && "Unexpected unsupported dependency type!");
+ assert(DE.Type == DependencyEdge::DT_RESOURCE &&
+ "Unexpected unsupported dependency type!");
OS << " - RESOURCE MASK: " << DE.ResourceOrRegID;
}
- OS << " - CYCLES: " << DE.Cycles << '\n';
+ OS << " - CYCLES: " << DE.Cost << '\n';
}
void DependencyGraph::dump(raw_ostream &OS, MCInstPrinter &MCIP) const {
OS << "\nREG DEPS\n";
- for (unsigned I = 0, E = Nodes.size(); I < E; ++I) {
- const DGNode &Node = Nodes[I];
- for (const DependencyEdge &DE : Node.OutgoingEdges) {
- if (DE.Type == DT_REGISTER)
- dumpDependencyEdge(OS, I, DE, MCIP);
- }
- }
+ for (const DGNode &Node : Nodes)
+ for (const DependencyEdge &DE : Node.OutgoingEdges)
+ if (DE.Dep.Type == DependencyEdge::DT_REGISTER)
+ dumpDependencyEdge(OS, DE, MCIP);
OS << "\nMEM DEPS\n";
- for (unsigned I = 0, E = Nodes.size(); I < E; ++I) {
- const DGNode &Node = Nodes[I];
- for (const DependencyEdge &DE : Node.OutgoingEdges) {
- if (DE.Type == DT_MEMORY)
- dumpDependencyEdge(OS, I, DE, MCIP);
- }
- }
+ for (const DGNode &Node : Nodes)
+ for (const DependencyEdge &DE : Node.OutgoingEdges)
+ if (DE.Dep.Type == DependencyEdge::DT_MEMORY)
+ dumpDependencyEdge(OS, DE, MCIP);
OS << "\nRESOURCE DEPS\n";
- for (unsigned I = 0, E = Nodes.size(); I < E; ++I) {
- const DGNode &Node = Nodes[I];
- for (const DependencyEdge &DE : Node.OutgoingEdges) {
- if (DE.Type == DT_RESOURCE)
- dumpDependencyEdge(OS, I, DE, MCIP);
- }
- }
+ for (const DGNode &Node : Nodes)
+ for (const DependencyEdge &DE : Node.OutgoingEdges)
+ if (DE.Dep.Type == DependencyEdge::DT_RESOURCE)
+ dumpDependencyEdge(OS, DE, MCIP);
}
#endif // NDEBUG
-void DependencyGraph::addDependency(unsigned From, DependencyEdge &&Dep) {
+void DependencyGraph::addDependency(unsigned From, unsigned To,
+ DependencyEdge::Dependency &&Dep) {
DGNode &NodeFrom = Nodes[From];
- DGNode &NodeTo = Nodes[Dep.IID];
+ DGNode &NodeTo = Nodes[To];
SmallVectorImpl<DependencyEdge> &Vec = NodeFrom.OutgoingEdges;
- auto It = find_if(Vec, [Dep](DependencyEdge &DE) {
- return DE.IID == Dep.IID && DE.ResourceOrRegID == Dep.ResourceOrRegID;
+ auto It = find_if(Vec, [To, Dep](DependencyEdge &DE) {
+ return DE.ToIID == To && DE.Dep.ResourceOrRegID == Dep.ResourceOrRegID;
});
if (It != Vec.end()) {
- It->Cycles += Dep.Cycles;
+ It->Dep.Cost += Dep.Cost;
return;
}
- Vec.emplace_back(Dep);
+ DependencyEdge DE = {Dep, From, To};
+ Vec.emplace_back(DE);
NodeTo.NumPredecessors++;
}
BottleneckAnalysis::BottleneckAnalysis(const MCSubtargetInfo &sti,
MCInstPrinter &Printer,
- ArrayRef<MCInst> S)
+ ArrayRef<MCInst> S, unsigned NumIter)
: STI(sti), Tracker(STI.getSchedModel()), DG(S.size() * 3),
- Source(S), TotalCycles(0), PressureIncreasedBecauseOfResources(false),
+ Source(S), Iterations(NumIter), TotalCycles(0),
+ PressureIncreasedBecauseOfResources(false),
PressureIncreasedBecauseOfRegisterDependencies(false),
PressureIncreasedBecauseOfMemoryDependencies(false),
SeenStallCycles(false), BPI() {}
void BottleneckAnalysis::addRegisterDep(unsigned From, unsigned To,
- unsigned RegID, unsigned Cy) {
+ unsigned RegID, unsigned Cost) {
bool IsLoopCarried = From >= To;
unsigned SourceSize = Source.size();
if (IsLoopCarried) {
- DG.addRegisterDep(From, To + SourceSize, RegID, Cy);
- DG.addRegisterDep(From + SourceSize, To + (SourceSize * 2), RegID, Cy);
+ Cost *= Iterations / 2;
+ DG.addRegisterDep(From, To + SourceSize, RegID, Cost);
+ DG.addRegisterDep(From + SourceSize, To + (SourceSize * 2), RegID, Cost);
return;
}
- DG.addRegisterDep(From + SourceSize, To + SourceSize, RegID, Cy);
+ DG.addRegisterDep(From + SourceSize, To + SourceSize, RegID, Cost);
}
-void BottleneckAnalysis::addMemoryDep(unsigned From, unsigned To, unsigned Cy) {
+void BottleneckAnalysis::addMemoryDep(unsigned From, unsigned To,
+ unsigned Cost) {
bool IsLoopCarried = From >= To;
unsigned SourceSize = Source.size();
if (IsLoopCarried) {
- DG.addMemoryDep(From, To + SourceSize, Cy);
- DG.addMemoryDep(From + SourceSize, To + (SourceSize * 2), Cy);
+ Cost *= Iterations / 2;
+ DG.addMemoryDep(From, To + SourceSize, Cost);
+ DG.addMemoryDep(From + SourceSize, To + (SourceSize * 2), Cost);
return;
}
- DG.addMemoryDep(From + SourceSize, To + SourceSize, Cy);
+ DG.addMemoryDep(From + SourceSize, To + SourceSize, Cost);
}
void BottleneckAnalysis::addResourceDep(unsigned From, unsigned To,
- uint64_t Mask, unsigned Cy) {
+ uint64_t Mask, unsigned Cost) {
bool IsLoopCarried = From >= To;
unsigned SourceSize = Source.size();
if (IsLoopCarried) {
- DG.addResourceDep(From, To + SourceSize, Mask, Cy);
- DG.addResourceDep(From + SourceSize, To + (SourceSize * 2), Mask, Cy);
+ Cost *= Iterations / 2;
+ DG.addResourceDep(From, To + SourceSize, Mask, Cost);
+ DG.addResourceDep(From + SourceSize, To + (SourceSize * 2), Mask, Cost);
return;
}
- DG.addResourceDep(From + SourceSize, To + SourceSize, Mask, Cy);
+ DG.addResourceDep(From + SourceSize, To + SourceSize, Mask, Cost);
}
void BottleneckAnalysis::onEvent(const HWInstructionEvent &Event) {
diff --git a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h
index 9268e4935c1..f8302496cef 100644
--- a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h
+++ b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h
@@ -115,16 +115,27 @@ public:
void handleInstructionIssuedEvent(const HWInstructionIssuedEvent &Event);
};
-class DependencyGraph {
- enum DependencyType { DT_REGISTER, DT_MEMORY, DT_RESOURCE };
-
- struct DependencyEdge {
+// An edge of a dependency graph.
+// Vertices of the graph are instructions identified by their ID.
+struct DependencyEdge {
+ enum DependencyType { DT_INVALID, DT_REGISTER, DT_MEMORY, DT_RESOURCE };
+
+ // Dependency edge descriptor.
+ //
+ // It describe the dependency reason, as well as the edge cost in cycles.
+ struct Dependency {
DependencyType Type;
- unsigned IID;
uint64_t ResourceOrRegID;
- uint64_t Cycles;
+ uint64_t Cost;
};
+ Dependency Dep;
+
+ // Pair of vertices connected by this edge.
+ unsigned FromIID;
+ unsigned ToIID;
+};
+class DependencyGraph {
struct DGNode {
unsigned NumPredecessors;
SmallVector<DependencyEdge, 8> OutgoingEdges;
@@ -134,26 +145,29 @@ class DependencyGraph {
DependencyGraph(const DependencyGraph &) = delete;
DependencyGraph &operator=(const DependencyGraph &) = delete;
- void addDependency(unsigned From, DependencyEdge &&DE);
+ void addDependency(unsigned From, unsigned To,
+ DependencyEdge::Dependency &&DE);
#ifndef NDEBUG
- void dumpDependencyEdge(raw_ostream &OS, unsigned FromIID,
- const DependencyEdge &DE, MCInstPrinter &MCIP) const;
+ void dumpDependencyEdge(raw_ostream &OS, const DependencyEdge &DE,
+ MCInstPrinter &MCIP) const;
#endif
public:
DependencyGraph(unsigned Size) : Nodes(Size) {}
- void addRegisterDep(unsigned From, unsigned To, unsigned RegID, unsigned Cy) {
- addDependency(From, {DT_REGISTER, To, RegID, Cy});
+ void addRegisterDep(unsigned From, unsigned To, unsigned RegID,
+ unsigned Cost) {
+ addDependency(From, To, {DependencyEdge::DT_REGISTER, RegID, Cost});
}
- void addMemoryDep(unsigned From, unsigned To, unsigned Cy) {
- addDependency(From, {DT_MEMORY, To, /* unused */ 0, Cy});
+ void addMemoryDep(unsigned From, unsigned To, unsigned Cost) {
+ addDependency(From, To, {DependencyEdge::DT_MEMORY, /* unused */ 0, Cost});
}
- void addResourceDep(unsigned From, unsigned To, uint64_t Mask, unsigned Cy) {
- addDependency(From, {DT_RESOURCE, To, Mask, Cy});
+ void addResourceDep(unsigned From, unsigned To, uint64_t Mask,
+ unsigned Cost) {
+ addDependency(From, To, {DependencyEdge::DT_RESOURCE, Mask, Cost});
}
#ifndef NDEBUG
@@ -168,6 +182,7 @@ class BottleneckAnalysis : public View {
DependencyGraph DG;
ArrayRef<MCInst> Source;
+ unsigned Iterations;
unsigned TotalCycles;
bool PressureIncreasedBecauseOfResources;
@@ -190,17 +205,17 @@ class BottleneckAnalysis : public View {
};
BackPressureInfo BPI;
- // Prints a bottleneck message to OS.
- void printBottleneckHints(raw_ostream &OS) const;
-
// Used to populate the dependency graph DG.
void addRegisterDep(unsigned From, unsigned To, unsigned RegID, unsigned Cy);
void addMemoryDep(unsigned From, unsigned To, unsigned Cy);
void addResourceDep(unsigned From, unsigned To, uint64_t Mask, unsigned Cy);
+ // Prints a bottleneck message to OS.
+ void printBottleneckHints(raw_ostream &OS) const;
+
public:
BottleneckAnalysis(const MCSubtargetInfo &STI, MCInstPrinter &MCIP,
- ArrayRef<MCInst> Sequence);
+ ArrayRef<MCInst> Sequence, unsigned Iterations);
void onCycleEnd() override;
void onEvent(const HWStallEvent &Event) override { SeenStallCycles = true; }
diff --git a/llvm/tools/llvm-mca/llvm-mca.cpp b/llvm/tools/llvm-mca/llvm-mca.cpp
index afe06ba9da2..b3590b5910e 100644
--- a/llvm/tools/llvm-mca/llvm-mca.cpp
+++ b/llvm/tools/llvm-mca/llvm-mca.cpp
@@ -487,8 +487,10 @@ int main(int argc, char **argv) {
Printer.addView(
llvm::make_unique<mca::SummaryView>(SM, Insts, DispatchWidth));
- if (EnableBottleneckAnalysis)
- Printer.addView(llvm::make_unique<mca::BottleneckAnalysis>(*STI, *IP, Insts));
+ if (EnableBottleneckAnalysis) {
+ Printer.addView(llvm::make_unique<mca::BottleneckAnalysis>(
+ *STI, *IP, Insts, S.getNumIterations()));
+ }
if (PrintInstructionInfoView)
Printer.addView(
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