1 files changed, 100 insertions, 2 deletions

diff --git a/llvm/tools/llvm-mca/Views/SummaryView.cpp b/llvm/tools/llvm-mca/Views/SummaryView.cpp
index 1f14f3dcd91..59421604506 100644
--- a/llvm/tools/llvm-mca/Views/SummaryView.cpp
+++ b/llvm/tools/llvm-mca/Views/SummaryView.cpp
@@ -25,10 +25,14 @@ namespace mca {
 SummaryView::SummaryView(const MCSchedModel &Model, ArrayRef<MCInst> S,
                          unsigned Width)
     : SM(Model), Source(S), DispatchWidth(Width), LastInstructionIdx(0),
-      TotalCycles(0), NumMicroOps(0),
+      TotalCycles(0), NumMicroOps(0), BPI({0, 0, 0, 0}),
+      ResourcePressureDistribution(Model.getNumProcResourceKinds(), 0),
       ProcResourceUsage(Model.getNumProcResourceKinds(), 0),
       ProcResourceMasks(Model.getNumProcResourceKinds()),
-      ResIdx2ProcResID(Model.getNumProcResourceKinds(), 0) {
+      ResIdx2ProcResID(Model.getNumProcResourceKinds(), 0),
+      PressureIncreasedBecauseOfResources(false),
+      PressureIncreasedBecauseOfDataDependencies(false),
+      SeenStallCycles(false) {
   computeProcResourceMasks(SM, ProcResourceMasks);
   for (unsigned I = 1, E = SM.getNumProcResourceKinds(); I < E; ++I) {
     unsigned Index = getResourceStateIndex(ProcResourceMasks[I]);
@@ -61,6 +65,98 @@ void SummaryView::onEvent(const HWInstructionEvent &Event) {
   }
 }
 
+void SummaryView::onEvent(const HWPressureEvent &Event) {
+  assert(Event.Reason != HWPressureEvent::INVALID &&
+         "Unexpected invalid event!");
+
+  switch (Event.Reason) {
+  default:
+    break;
+
+  case HWPressureEvent::RESOURCES: {
+    PressureIncreasedBecauseOfResources = true;
+    ++BPI.ResourcePressureCycles;
+    uint64_t ResourceMask = Event.ResourceMask;
+    while (ResourceMask) {
+      uint64_t Current = ResourceMask & (-ResourceMask);
+      unsigned Index = getResourceStateIndex(Current);
+      unsigned ProcResID = ResIdx2ProcResID[Index];
+      const MCProcResourceDesc &PRDesc = *SM.getProcResource(ProcResID);
+      if (!PRDesc.SubUnitsIdxBegin) {
+        ResourcePressureDistribution[Index]++;
+        ResourceMask ^= Current;
+        continue;
+      }
+
+      for (unsigned I = 0, E = PRDesc.NumUnits; I < E; ++I) {
+        unsigned OtherProcResID = PRDesc.SubUnitsIdxBegin[I];
+        unsigned OtherMask = ProcResourceMasks[OtherProcResID];
+        ResourcePressureDistribution[getResourceStateIndex(OtherMask)]++;
+      }
+
+      ResourceMask ^= Current;
+    }
+  }
+
+  break;
+  case HWPressureEvent::REGISTER_DEPS:
+    PressureIncreasedBecauseOfDataDependencies = true;
+    ++BPI.RegisterDependencyCycles;
+    break;
+  case HWPressureEvent::MEMORY_DEPS:
+    PressureIncreasedBecauseOfDataDependencies = true;
+    ++BPI.MemoryDependencyCycles;
+    break;
+  }
+}
+
+void SummaryView::printBottleneckHints(raw_ostream &OS) const {
+  if (!SeenStallCycles || !BPI.PressureIncreaseCycles)
+    return;
+
+  double PressurePerCycle =
+      (double)BPI.PressureIncreaseCycles * 100 / TotalCycles;
+  double ResourcePressurePerCycle =
+      (double)BPI.ResourcePressureCycles * 100 / TotalCycles;
+  double DDPerCycle = (double)BPI.DataDependencyCycles * 100 / TotalCycles;
+  double RegDepPressurePerCycle =
+      (double)BPI.RegisterDependencyCycles * 100 / TotalCycles;
+  double MemDepPressurePerCycle =
+      (double)BPI.MemoryDependencyCycles * 100 / TotalCycles;
+
+  OS << "\nCycles with backend pressure increase [ "
+     << format("%.2f", floor((PressurePerCycle * 100) + 0.5) / 100) << "% ]";
+
+  OS << "\nThroughput Bottlenecks: "
+     << "\n  Resource Pressure       [ "
+     << format("%.2f", floor((ResourcePressurePerCycle * 100) + 0.5) / 100)
+     << "% ]";
+
+  if (BPI.PressureIncreaseCycles) {
+    for (unsigned I = 0, E = ResourcePressureDistribution.size(); I < E; ++I) {
+      if (ResourcePressureDistribution[I]) {
+        double Frequency =
+            (double)ResourcePressureDistribution[I] * 100 / TotalCycles;
+        unsigned Index = ResIdx2ProcResID[getResourceStateIndex(1ULL << I)];
+        const MCProcResourceDesc &PRDesc = *SM.getProcResource(Index);
+        OS << "\n  - " << PRDesc.Name << "  [ "
+           << format("%.2f", floor((Frequency * 100) + 0.5) / 100) << "% ]";
+      }
+    }
+  }
+
+  OS << "\n  Data Dependencies:      [ "
+     << format("%.2f", floor((DDPerCycle * 100) + 0.5) / 100) << "% ]";
+
+  OS << "\n  - Register Dependencies [ "
+     << format("%.2f", floor((RegDepPressurePerCycle * 100) + 0.5) / 100)
+     << "% ]";
+
+  OS << "\n  - Memory Dependencies   [ "
+     << format("%.2f", floor((MemDepPressurePerCycle * 100) + 0.5) / 100)
+     << "% ]\n\n";
+}
+
 void SummaryView::printView(raw_ostream &OS) const {
   unsigned Instructions = Source.size();
   unsigned Iterations = (LastInstructionIdx / Instructions) + 1;
@@ -85,6 +181,8 @@ void SummaryView::printView(raw_ostream &OS) const {
   TempStream << "\nBlock RThroughput: "
              << format("%.1f", floor((BlockRThroughput * 10) + 0.5) / 10)
              << '\n';
+
+  printBottleneckHints(TempStream);
   TempStream.flush();
   OS << Buffer;
 }