[BOLT][heatmap] Produce zoomed-out heatmaps

bolt/include/bolt/Profile/Heatmap.h

@@ -85,6 +85,9 @@ class Heatmap {
   void printSectionHotness(raw_ostream &OS) const;
 
   size_t size() const { return Map.size(); }
+
+  /// Increase bucket size to \p TargetSize, recomputing the heatmap.
+  bool resizeBucket(uint64_t TargetSize);
 };
 
 } // namespace bolt

bolt/lib/Profile/DataAggregator.cpp

@@ -68,6 +68,12 @@ FilterPID("pid",
   cl::Optional,
   cl::cat(AggregatorCategory));
 
+static cl::list<uint64_t>
+    HeatmapZoomOut("heatmap-zoom-out", cl::CommaSeparated,
+                   cl::desc("print secondary heatmaps with given bucket sizes"),
+                   cl::value_desc("bucket_size"), cl::Optional,
+                   cl::cat(HeatmapCategory));
+
 static cl::opt<bool>
 IgnoreBuildID("ignore-build-id",
   cl::desc("continue even if build-ids in input binary and perf.data mismatch"),
@@ -1365,6 +1371,15 @@ std::error_code DataAggregator::printLBRHeatMap() {
     HM.printCDF(opts::HeatmapOutput + ".csv");
     HM.printSectionHotness(opts::HeatmapOutput + "-section-hotness.csv");
   }
+  // Provide coarse-grained heatmap if requested via --heatmap-zoom-out
+  for (const uint64_t NewBucketSize : opts::HeatmapZoomOut) {
+    if (!HM.resizeBucket(NewBucketSize))
+      break;
+    if (opts::HeatmapOutput == "-")
+      HM.print(opts::HeatmapOutput);
+    else
+      HM.print(formatv("{0}-{1}", opts::HeatmapOutput, NewBucketSize).str());
+  }
 
   return std::error_code();
 }

bolt/lib/Profile/Heatmap.cpp

@@ -364,5 +364,18 @@ void Heatmap::printSectionHotness(raw_ostream &OS) const {
     OS << formatv("[unmapped], 0x0, 0x0, {0:f4}, 0, 0\n",
                   100.0 * UnmappedHotness / NumTotalCounts);
 }
+
+bool Heatmap::resizeBucket(uint64_t TargetSize) {
+  if (TargetSize <= BucketSize)
+    return false;
+  std::map<uint64_t, uint64_t> NewMap;
+  for (const auto [Bucket, Count] : Map) {
+    const uint64_t Address = Bucket * BucketSize;
+    NewMap[Address / TargetSize] += Count;
+  }
+  Map = NewMap;
+  BucketSize = TargetSize;
+  return true;
+}
 } // namespace bolt
 } // namespace llvm

bolt/test/X86/heatmap-preagg.test

@@ -3,8 +3,12 @@
 RUN: yaml2obj %p/Inputs/blarge_new.yaml &> %t.exe
 ## Non-BOLTed input binary
 RUN: llvm-bolt-heatmap %t.exe -o %t --pa -p %p/Inputs/blarge_new.preagg.txt \
+RUN:   --heatmap-zoom-out 128,1024 --line-size 64 \
 RUN:   2>&1 | FileCheck --check-prefix CHECK-HEATMAP %s
 RUN: FileCheck %s --check-prefix CHECK-SEC-HOT --input-file %t-section-hotness.csv
+RUN: FileCheck %s --check-prefix CHECK-HM-64 --input-file %t
+RUN: FileCheck %s --check-prefix CHECK-HM-128 --input-file %t-128
+RUN: FileCheck %s --check-prefix CHECK-HM-1024 --input-file %t-1024
 
 ## BOLTed input binary
 RUN: llvm-bolt %t.exe -o %t.out --pa -p %p/Inputs/blarge_new.preagg.txt \
@@ -24,6 +28,29 @@ CHECK-SEC-HOT-NEXT: .plt, 0x401020, 0x4010b0, 4.7583, 66.6667, 0.0317
 CHECK-SEC-HOT-NEXT: .text, 0x4010b0, 0x401c25, 78.3872, 85.1064, 0.6671
 CHECK-SEC-HOT-NEXT: .fini, 0x401c28, 0x401c35, 0.0000, 0.0000, 0.0000
 
+# Only check x scales – can't check colors, and FileCheck doesn't strip color
+# codes by default.
+CHECK-HM-64: (299, 937]
+CHECK-HM-64-NEXT:   0
+CHECK-HM-64-NEXT:   0
+CHECK-HM-64-NEXT:   0   1   2   3   4   5   6   7   8   9   a   b   c   d   e   f
+CHECK-HM-64-NEXT:   048c048c048c048c048c048c048c048c048c048c048c048c048c048c048c048c
+CHECK-HM-64-NEXT:   0
+
+CHECK-HM-128: (299, 937]
+CHECK-HM-128-NEXT:  0
+CHECK-HM-128-NEXT:  0                               1
+CHECK-HM-128-NEXT:  0 1 2 3 4 5 6 7 8 9 a b c d e f 0 1 2 3 4 5 6 7 8 9 a b c d e f
+CHECK-HM-128-NEXT:  0808080808080808080808080808080808080808080808080808080808080808
+CHECK-HM-128-NEXT:  0
+
+CHECK-HM-1024: (483, 1663]
+CHECK-HM-1024-NEXT: 0
+CHECK-HM-1024-NEXT: 0   1   2   3   4   5   6   7   8   9   a   b   c   d   e   f
+CHECK-HM-1024-NEXT: 048c048c048c048c048c048c048c048c048c048c048c048c048c048c048c048c
+CHECK-HM-1024-NEXT: 0
+CHECK-HM-1024-NEXT: 0
+
 CHECK-HEATMAP-BAT: PERF2BOLT: read 79 aggregated LBR entries
 CHECK-HEATMAP-BAT: HEATMAP: invalid traces: 2