Slim ThreadStressLogData and simplify GetStressMessages API

docs/design/datacontracts/StressLog.md

@@ -18,13 +18,8 @@ internal record struct StressLogData(
 
 internal record struct ThreadStressLogData(
     TargetPointer Address,
-    TargetPointer NextPointer,
     ulong ThreadId,
-    bool WriteHasWrapped,
-    TargetPointer CurrentPointer,
-    TargetPointer ChunkListHead,
-    TargetPointer ChunkListTail,
-    TargetPointer CurrentWriteChunk);
+    bool WriteHasWrapped);
 
 internal record struct StressMsgData(
     uint Facility,
@@ -38,7 +33,7 @@ bool HasStressLog();
 StressLogData GetStressLogData();
 StressLogData GetStressLogData(TargetPointer stressLogPointer);
 IEnumerable<ThreadStressLogData> GetThreadStressLogs(TargetPointer logs);
-IEnumerable<StressMsgData> GetStressMessages(ThreadStressLogData threadLog);
+IEnumerable<StressMsgData> GetStressMessages(TargetPointer threadStressLogAddress);
 bool IsPointerInStressLog(StressLogData stressLog, TargetPointer pointer);
 ```
 
@@ -67,7 +62,6 @@ Data descriptors used:
 | ThreadStressLog | ChunkListHead | Pointer to the head of the chunk list |
 | ThreadStressLog | ChunkListTail | Pointer to the tail of the chunk list |
 | ThreadStressLog | CurrentWriteChunk | Pointer to the chunk currently being written to |
-| StressLogChunk | Prev | Pointer to the previous chunk |
 | StressLogChunk | Next | Pointer to the next chunk |
 | StressLogChunk | Buf | The data stored in the chunk |
 | StressLogChunk | Sig1 | First byte of the chunk signature (to ensure validity) |
@@ -157,20 +151,15 @@ IEnumerable<ThreadStressLogData> GetThreadStressLogs(TargetPointer logs)
 
         yield return new ThreadStressLogData(
             currentPointer,
-            threadStressLog.Next,
             threadStressLog.ThreadId,
-            threadStressLog.WriteHasWrapped,
-            threadStressLog.CurrentPtr,
-            threadStressLog.ChunkListHead,
-            threadStressLog.ChunkListTail,
-            threadStressLog.CurrentWriteChunk);
+            threadStressLog.WriteHasWrapped);
 
         currentPointer = threadStressLog.Next;
     }
 }
 
 // Return messages going in reverse chronological order, newest first.
-IEnumerable<StressMsgData> GetStressMessages(ThreadStressLogData threadLog)
+IEnumerable<StressMsgData> GetStressMessages(TargetPointer threadStressLogAddress)
 {
     // 1. Get the current message pointer from the log and the info about the current chunk the runtime is writing into.
     //    Record our current read pointer as the current message pointer.

src/coreclr/vm/datadescriptor/datadescriptor.inc

@@ -641,7 +641,6 @@ CDAC_TYPE_END(ThreadStressLog)
 
 CDAC_TYPE_BEGIN(StressLogChunk)
 CDAC_TYPE_SIZE(sizeof(StressLogChunk))
-CDAC_TYPE_FIELD(StressLogChunk, T_POINTER, Prev, offsetof(StressLogChunk, prev))
 CDAC_TYPE_FIELD(StressLogChunk, T_POINTER, Next, offsetof(StressLogChunk, next))
 CDAC_TYPE_FIELD(StressLogChunk, T_ARRAY(T_UINT8), Buf, offsetof(StressLogChunk, buf))
 CDAC_TYPE_FIELD(StressLogChunk, T_UINT32, Sig1, offsetof(StressLogChunk, dwSig1))

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IStressLog.cs

@@ -19,13 +19,8 @@ public record struct StressLogData(
 
 public record struct ThreadStressLogData(
     TargetPointer Address,
-    TargetPointer NextPointer,
     ulong ThreadId,
-    bool WriteHasWrapped,
-    TargetPointer CurrentPointer,
-    TargetPointer ChunkListHead,
-    TargetPointer ChunkListTail,
-    TargetPointer CurrentWriteChunk);
+    bool WriteHasWrapped);
 
 public record struct StressMsgData(
     uint Facility,
@@ -40,7 +35,7 @@ public interface IStressLog : IContract
     StressLogData GetStressLogData() => throw new NotImplementedException();
     StressLogData GetStressLogData(TargetPointer stressLog) => throw new NotImplementedException();
     IEnumerable<ThreadStressLogData> GetThreadStressLogs(TargetPointer Logs) => throw new NotImplementedException();
-    IEnumerable<StressMsgData> GetStressMessages(ThreadStressLogData threadLog) => throw new NotImplementedException();
+    IEnumerable<StressMsgData> GetStressMessages(TargetPointer threadStressLogAddress) => throw new NotImplementedException();
     bool IsPointerInStressLog(StressLogData stressLog, TargetPointer pointer) => throw new NotImplementedException();
 }
 

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Constants.cs

@@ -60,7 +60,6 @@ public static class Globals
         public const string StressLog = nameof(StressLog);
         public const string StressLogModuleTable = nameof(StressLogModuleTable);
         public const string StressLogMaxModules = nameof(StressLogMaxModules);
-        public const string StressLogChunkMaxSize = nameof(StressLogChunkMaxSize);
         public const string StressLogMaxMessageSize = nameof(StressLogMaxMessageSize);
         public const string StressLogChunkSize = nameof(StressLogChunkSize);
         public const string StressLogValidChunkSig = nameof(StressLogValidChunkSig);

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/StressLog.cs

@@ -81,13 +81,8 @@ public IEnumerable<ThreadStressLogData> GetThreadStressLogs(TargetPointer Logs)
 
             yield return new ThreadStressLogData(
                 currentPointer,
-                threadStressLog.Next,
                 threadStressLog.ThreadId,
-                threadStressLog.WriteHasWrapped,
-                threadStressLog.CurrentPtr,
-                threadStressLog.ChunkListHead,
-                threadStressLog.ChunkListTail,
-                threadStressLog.CurrentWriteChunk);
+                threadStressLog.WriteHasWrapped);
 
             currentPointer = threadStressLog.Next;
         }
@@ -128,18 +123,20 @@ private TargetPointer GetFormatPointer(ulong formatOffset)
         return TargetPointer.Null;
     }
 
-    public IEnumerable<StressMsgData> GetStressMessages(ThreadStressLogData threadLog)
+    public IEnumerable<StressMsgData> GetStressMessages(TargetPointer threadStressLogAddress)
     {
         uint stressMsgHeaderSize = target.GetTypeInfo(DataType.StressMsgHeader).Size!.Value;
         uint pointerSize = (uint)target.PointerSize;
 
+        Data.ThreadStressLog threadLog = target.ProcessedData.GetOrAdd<Data.ThreadStressLog>(threadStressLogAddress);
+
         Data.StressLogChunk currentChunkData = target.ProcessedData.GetOrAdd<Data.StressLogChunk>(threadLog.CurrentWriteChunk);
         TargetPointer currentReadChunk = threadLog.CurrentWriteChunk;
-        TargetPointer readPointer = threadLog.CurrentPointer;
+        TargetPointer readPointer = threadLog.CurrentPtr;
         bool readHasWrapped = false;
         uint chunkSize = target.ReadGlobal<uint>(Constants.Globals.StressLogChunkSize);
 
-        TargetPointer currentPointer = threadLog.CurrentPointer;
+        TargetPointer currentPointer = threadLog.CurrentPtr;
         // the last written log, if it wrapped around may have partially overwritten
         // a previous record.  Update currentPointer to reflect the last safe beginning of a record,
         // but currentPointer shouldn't wrap around, otherwise it'll break our assumptions about stress
@@ -341,7 +338,7 @@ internal sealed class StressLog_1(Target target) : IStressLog
     public StressLogData GetStressLogData() => traversal.GetStressLogData();
     public StressLogData GetStressLogData(TargetPointer stressLog) => traversal.GetStressLogData(stressLog);
     public IEnumerable<ThreadStressLogData> GetThreadStressLogs(TargetPointer Logs) => traversal.GetThreadStressLogs(Logs);
-    public IEnumerable<StressMsgData> GetStressMessages(ThreadStressLogData threadLog) => traversal.GetStressMessages(threadLog);
+    public IEnumerable<StressMsgData> GetStressMessages(TargetPointer threadStressLogAddress) => traversal.GetStressMessages(threadStressLogAddress);
     public bool IsPointerInStressLog(StressLogData stressLog, TargetPointer pointer) => traversal.IsPointerInStressLog(stressLog, pointer);
 }
 
@@ -354,6 +351,6 @@ internal sealed class StressLog_2(Target target) : IStressLog
     public StressLogData GetStressLogData() => traversal.GetStressLogData();
     public StressLogData GetStressLogData(TargetPointer stressLog) => traversal.GetStressLogData(stressLog);
     public IEnumerable<ThreadStressLogData> GetThreadStressLogs(TargetPointer Logs) => traversal.GetThreadStressLogs(Logs);
-    public IEnumerable<StressMsgData> GetStressMessages(ThreadStressLogData threadLog) => traversal.GetStressMessages(threadLog);
+    public IEnumerable<StressMsgData> GetStressMessages(TargetPointer threadStressLogAddress) => traversal.GetStressMessages(threadStressLogAddress);
     public bool IsPointerInStressLog(StressLogData stressLog, TargetPointer pointer) => traversal.IsPointerInStressLog(stressLog, pointer);
 }

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/StressLogChunk.cs

@@ -7,7 +7,6 @@ namespace Microsoft.Diagnostics.DataContractReader.Data;
 internal sealed partial class StressLogChunk : IData<StressLogChunk>
 {
     [Field] public TargetPointer Next { get; }
-    [Field] public TargetPointer Prev { get; }
 
     [FieldAddress]
     public TargetPointer Buf { get; }

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/SOSDacImpl.cs

@@ -7320,23 +7320,8 @@ int ISOSDacInterface17.GetStressLogMessageEnumerator(
             if (!stressLogContract.HasStressLog())
                 return HResults.S_FALSE;
 
-            Contracts.StressLogData logData = stressLogContract.GetStressLogData();
-
-            // Find the matching thread
-            Contracts.ThreadStressLogData? matchedThread = null;
-            foreach (var thread in stressLogContract.GetThreadStressLogs(logData.Logs))
-            {
-                if (thread.Address == threadStressLogAddress.ToTargetPointer(_target))
-                {
-                    matchedThread = thread;
-                    break;
-                }
-            }
-
-            if (matchedThread is null)
-                return HResults.E_INVALIDARG;
-
-            IEnumerable<Contracts.StressMsgData> messages = stressLogContract.GetStressMessages(matchedThread.Value);
+            TargetPointer address = threadStressLogAddress.ToTargetPointer(_target);
+            IEnumerable<Contracts.StressMsgData> messages = stressLogContract.GetStressMessages(address);
             ppEnum.Interface = new SOSStressLogMsgEnum(_target, messages);
         }
         catch (System.Exception ex)

src/native/managed/cdac/tests/DumpTests/StressLogDumpTests.cs

@@ -55,7 +55,7 @@ public void CanEnumerateThreadsAndMessages(TestConfiguration config)
         bool foundMessages = false;
         foreach (ThreadStressLogData thread in threads)
         {
-            var messages = stressLog.GetStressMessages(thread).Take(10).ToList();
+            var messages = stressLog.GetStressMessages(thread.Address).Take(10).ToList();
             if (messages.Count > 0)
             {
                 foundMessages = true;

src/tools/StressLogAnalyzer/src/Program.cs

@@ -585,7 +585,7 @@ private static ContractDescriptorParser.ContractDescriptor GetDescriptor(string
                     "StressLogModuleTable": [[ 1 ], "pointer" ],
                 },
                 "contracts": {
-                    "StressLog": 2,
+                    "StressLog": "c2",
                 }
             }
             """"u8)!;

src/tools/StressLogAnalyzer/src/StressLogAnalyzer.cs

@@ -32,7 +32,7 @@ internal sealed class StressLogAnalyzer(
         // The "end" timestamp is the timestamp of the most recent message.
         timeTracker.SetEndTimestamp(
             logs.Select(
-                log => outerLogContract.GetStressMessages(log).FirstOrDefault().Timestamp)
+                log => outerLogContract.GetStressMessages(log.Address).FirstOrDefault().Timestamp)
             .Max());
 
         if (!threadFilter.HasAnyGCThreadFilter)
@@ -58,7 +58,7 @@ await Parallel.ForEachAsync(logs, parallelOptions, (log, ct) =>
                 StressMsgData? earliestMessage = null;
                 List<StressMsgData> localMessages = [];
                 bool includeThreadMessages = true;
-                foreach (StressMsgData message in stressLogContract.Value!.GetStressMessages(log))
+                foreach (StressMsgData message in stressLogContract.Value!.GetStressMessages(log.Address))
                 {
                     numMessagesProcessed.Value++;
                     token.ThrowIfCancellationRequested();