Use better lock, include overlap in graph titles, minor other fixes

src/coreclr/jit/codegencommon.cpp

@@ -10843,10 +10843,8 @@ void CodeGen::genDumpPreciseDebugInfo()
     if (JitConfig.JitDumpPreciseDebugInfoFile() == nullptr)
         return;
 
-    static unsigned int s_flag;
-
-    while (InterlockedCompareExchange(&s_flag, 1, 0) != 0)
-        System_YieldProcessor();
+    static CritSecObject s_critSect;
+    CritSecHolder holder(s_critSect);
 
     FILE* file = _wfopen(JitConfig.JitDumpPreciseDebugInfoFile(), W("a"));
     if (file == nullptr)
@@ -10878,8 +10876,6 @@ void CodeGen::genDumpPreciseDebugInfo()
     fprintf(file, "]}\n");
 
     fclose(file);
-
-    InterlockedCompareExchange(&s_flag, 0, 1);
 }
 
 void CodeGen::genAddPreciseIPMappingHere(const DebugInfo& di)

src/coreclr/tools/dotnet-pgo/MethodMemoryMap.cs

@@ -51,7 +51,7 @@ public MethodMemoryMap(
             TraceTypeSystemContext tsc,
             TraceRuntimeDescToTypeSystemDesc idParser,
             int clrInstanceID,
-            string preciseDebugInfoFile,
+            FileInfo preciseDebugInfoFile,
             Logger logger)
         {
             // Capture the addresses of jitted code
@@ -161,10 +161,10 @@ public MethodMemoryMap(
             }
 
             List<PreciseDebugInfo> preciseInfos = null;
-            if (File.Exists(preciseDebugInfoFile))
+            if (preciseDebugInfoFile != null)
             {
                 preciseInfos =
-                    File.ReadAllLines(preciseDebugInfoFile)
+                    File.ReadAllLines(preciseDebugInfoFile.FullName)
                     .Select(l => JsonSerializer.Deserialize<PreciseDebugInfo>(l))
                     .ToList();
             }

src/coreclr/tools/dotnet-pgo/Program.cs

@@ -623,21 +623,46 @@ string FormatDevirt(GetLikelyClassResult result)
 
                 if (options.DumpWorstOverlapGraphsTo != null)
                 {
-                    IEnumerable<(MethodDesc Method, double Overlap)> toDump;
+                    IEnumerable<MethodDesc> toDump;
                     if (options.DumpWorstOverlapGraphs == -1)
-                        toDump = blockOverlaps.OrderBy(t => t.Overlap).TakeWhile(t => t.Overlap < 0.5);
+                    {
+                        // Take all with less than 0.5 overlap in order.
+                        toDump =
+                            blockOverlaps
+                            .Concat(edgeOverlaps)
+                            .OrderBy(t => t.Overlap)
+                            .TakeWhile(t => t.Overlap < 0.5)
+                            .Select(t => t.Method)
+                            .Distinct();
+                    }
                     else
-                        toDump = blockOverlaps.OrderBy(t => t.Overlap).Take(options.DumpWorstOverlapGraphs);
+                    {
+                        // Take the first N methods ordered by min(blockOverlap, edgeOverlap).
+                        toDump =
+                            blockOverlaps
+                            .Concat(edgeOverlaps)
+                            .GroupBy(t => t.Method)
+                            .Select(g => (Method: g.Key, Overlap: g.Select(t => t.Overlap).Min()))
+                            .OrderBy(t => t.Overlap)
+                            .Select(t => t.Method)
+                            .Take(options.DumpWorstOverlapGraphs);
+                    }
 
-                    foreach ((MethodDesc method, double overlap) in toDump)
+                    foreach (MethodDesc method in toDump)
                     {
                         PgoCompareMethodFlowGraph fg = fgMatches[method];
 
                         string title = $"Flowgraph for {method}\\n{name1} vs {name2}";
                         if (fg.ProfilesHadBasicBlocks)
+                        {
                             title += $"\\nBasic block counts: {fg.TotalBlockCount1} vs {fg.TotalEdgeCount2}";
+                            title += $"\\nBasic block count overlap: {fg.ComputeBlockOverlap() * 100:F2}%";
+                        }
                         if (fg.ProfilesHadEdges)
-                            title += $"\\Edge counts: {fg.TotalEdgeCount1} vs {fg.TotalEdgeCount2}";
+                        {
+                            title += $"\\nEdge counts: {fg.TotalEdgeCount1} vs {fg.TotalEdgeCount2}";
+                            title += $"\\nEdge count overlap: {fg.ComputeEdgeOverlap() * 100:F2}%";
+                        }
 
                         string dot = fg.Dump(title);
 
@@ -1290,7 +1315,7 @@ MethodMemoryMap GetMethodMemMap()
                             tsc,
                             idParser,
                             clrInstanceId.Value,
-                            commandLineOptions.PreciseDebugInfoFile?.FullName,
+                            commandLineOptions.PreciseDebugInfoFile,
                             s_logger);
                     }
 

src/coreclr/tools/dotnet-pgo/SPGO/SampleCorrelator.cs

@@ -14,7 +14,7 @@
 namespace Microsoft.Diagnostics.Tools.Pgo
 {
     /// <summary>
-    /// A class that handles correlation IP samples/LBR samples back to managed methods.
+    /// A class that handles correlating IP samples/LBR samples back to managed methods.
     /// </summary>
     internal class SampleCorrelator
     {