diff --git a/src/TraceEvent/Computers/SampleProfilerThreadTimeComputer.cs b/src/TraceEvent/Computers/SampleProfilerThreadTimeComputer.cs
index 045c97243..1ee6d6da7 100644
--- a/src/TraceEvent/Computers/SampleProfilerThreadTimeComputer.cs
+++ b/src/TraceEvent/Computers/SampleProfilerThreadTimeComputer.cs
@@ -41,6 +41,13 @@ public SampleProfilerThreadTimeComputer(TraceLog eventLog, SymbolReader symbolRe
         /// If set we compute thread time using Tasks
         /// </summary>
         public bool UseTasks;
+
+        /// <summary>
+        /// Track additional info on like EventName or so.
+        /// Default to true to keep backward compatibility.
+        /// </summary>
+        public bool TrackAdditionalInfo = true;
+
         /// <summary>
         /// Use start-stop activities as the grouping construct. 
         /// </summary>
@@ -202,17 +209,20 @@ public void GenerateThreadTimeStacks(MutableTraceEventStackSource outputStackSou
 
                 StackSourceCallStackIndex stackIndex = GetCallStack(data, thread);
 
-                // Tack on additional info about the event. 
-                var fieldNames = data.PayloadNames;
-                for (int i = 0; i < fieldNames.Length; i++)
+                // Tack on additional info about the event.
+                if (TrackAdditionalInfo)
                 {
-                    var fieldName = fieldNames[i];
-                    var value = data.PayloadString(i);
-                    var fieldNodeName = "EventData: " + fieldName + "=" + value;
-                    var fieldNodeIndex = m_outputStackSource.Interner.FrameIntern(fieldNodeName);
-                    stackIndex = m_outputStackSource.Interner.CallStackIntern(fieldNodeIndex, stackIndex);
+                    var fieldNames = data.PayloadNames;
+                    for (int i = 0; i < fieldNames.Length; i++)
+                    {
+                        var fieldName = fieldNames[i];
+                        var value = data.PayloadString(i);
+                        var fieldNodeName = "EventData: " + fieldName + "=" + value;
+                        var fieldNodeIndex = m_outputStackSource.Interner.FrameIntern(fieldNodeName);
+                        stackIndex = m_outputStackSource.Interner.CallStackIntern(fieldNodeIndex, stackIndex);
+                    }
+                    stackIndex = m_outputStackSource.Interner.CallStackIntern(m_outputStackSource.Interner.FrameIntern("EventName: " + data.ProviderName + "/" + data.EventName), stackIndex);
                 }
-                stackIndex = m_outputStackSource.Interner.CallStackIntern(m_outputStackSource.Interner.FrameIntern("EventName: " + data.ProviderName + "/" + data.EventName), stackIndex);
 
                 m_threadState[(int)thread.ThreadIndex].LogThreadStack(data.TimeStampRelativeMSec, stackIndex, thread, this, false);
             };
diff --git a/src/TraceEvent/Computers/ThreadTimeComputer.cs b/src/TraceEvent/Computers/ThreadTimeComputer.cs
index 2370a2084..c958f764a 100644
--- a/src/TraceEvent/Computers/ThreadTimeComputer.cs
+++ b/src/TraceEvent/Computers/ThreadTimeComputer.cs
@@ -55,6 +55,11 @@ public ThreadTimeStackComputer(TraceLog eventLog, SymbolReader symbolReader)
         /// </summary>
         public bool UseTasks;
         /// <summary>
+        /// Track additional info on like EventName or so.
+        /// Default to true to keep backward compatibility.
+        /// </summary>
+        public bool TrackAdditionalInfo = true;
+        /// <summary>
         /// If set we compute blocked time 
         /// </summary>
         [Obsolete("Use Thread Time instead")]
@@ -296,17 +301,20 @@ public void GenerateThreadTimeStacks(MutableTraceEventStackSource outputStackSou
 
                 StackSourceCallStackIndex stackIndex = GetCallStack(data, thread);
 
-                // Tack on additional info about the event. 
-                var fieldNames = data.PayloadNames;
-                for (int i = 0; i < fieldNames.Length; i++)
+                // Tack on additional info about the event.
+                if (TrackAdditionalInfo)
                 {
-                    var fieldName = fieldNames[i];
-                    var value = data.PayloadString(i);
-                    var fieldNodeName = "EventData: " + fieldName + "=" + value;
-                    var fieldNodeIndex = m_outputStackSource.Interner.FrameIntern(fieldNodeName);
-                    stackIndex = m_outputStackSource.Interner.CallStackIntern(fieldNodeIndex, stackIndex);
+                    var fieldNames = data.PayloadNames;
+                    for (int i = 0; i < fieldNames.Length; i++)
+                    {
+                        var fieldName = fieldNames[i];
+                        var value = data.PayloadString(i);
+                        var fieldNodeName = "EventData: " + fieldName + "=" + value;
+                        var fieldNodeIndex = m_outputStackSource.Interner.FrameIntern(fieldNodeName);
+                        stackIndex = m_outputStackSource.Interner.CallStackIntern(fieldNodeIndex, stackIndex);
+                    }
+                    stackIndex = m_outputStackSource.Interner.CallStackIntern(m_outputStackSource.Interner.FrameIntern("EventName: " + data.ProviderName + "/" + data.EventName), stackIndex);
                 }
-                stackIndex = m_outputStackSource.Interner.CallStackIntern(m_outputStackSource.Interner.FrameIntern("EventName: " + data.ProviderName + "/" + data.EventName), stackIndex);
 
                 m_threadState[(int)thread.ThreadIndex].LogCPUStack(data.TimeStampRelativeMSec, stackIndex, thread, this, false);
             };
diff --git a/src/TraceEvent/Symbols/NativeSymbolModule.cs b/src/TraceEvent/Symbols/NativeSymbolModule.cs
index 2c007e514..e41d35259 100644
--- a/src/TraceEvent/Symbols/NativeSymbolModule.cs
+++ b/src/TraceEvent/Symbols/NativeSymbolModule.cs
@@ -107,32 +107,35 @@ public string FindNameForRva(uint rva, ref uint symbolStartRva)
                 ret = ret.Substring(0, dollarIdx);
 
             // See if we have a Project N map that maps $_NN to a pre-merged assembly name 
-            var mergedAssembliesMap = GetMergedAssembliesMap();
-            if (mergedAssembliesMap != null)
+            if (LookupAssemblyNameForCompiledNative)
             {
-                bool prefixMatchFound = false;
-                Regex prefixMatch = new Regex(@"\$(\d+)_");
-                ret = prefixMatch.Replace(ret, delegate (Match m)
+                var mergedAssembliesMap = GetMergedAssembliesMap();
+                if (mergedAssembliesMap != null)
                 {
-                    prefixMatchFound = true;
-                    var original = m.Groups[1].Value;
-                    var moduleIndex = int.Parse(original);
-                    string fullAssemblyName;
-                    if (mergedAssembliesMap.TryGetValue(moduleIndex, out fullAssemblyName))
+                    bool prefixMatchFound = false;
+                    Regex prefixMatch = new Regex(@"\$(\d+)_");
+                    ret = prefixMatch.Replace(ret, delegate (Match m)
                     {
-                        try
+                        prefixMatchFound = true;
+                        var original = m.Groups[1].Value;
+                        var moduleIndex = int.Parse(original);
+                        string fullAssemblyName;
+                        if (mergedAssembliesMap.TryGetValue(moduleIndex, out fullAssemblyName))
                         {
-                            var assemblyName = new AssemblyName(fullAssemblyName);
-                            return assemblyName.Name + "!";
+                            try
+                            {
+                                var assemblyName = new AssemblyName(fullAssemblyName);
+                                return assemblyName.Name + "!";
+                            }
+                            catch (Exception) { } // Catch all AssemlyName fails with ' in the name.   
                         }
-                        catch (Exception) { } // Catch all AssemlyName fails with ' in the name.   
-                    }
-                    return original;
-                });
+                        return original;
+                    });
 
-                // corefx.dll does not have a tag.  TODO this feels like a hack!
-                if (!prefixMatchFound)
-                    ret = "mscorlib!" + ret;
+                    // corefx.dll does not have a tag.  TODO this feels like a hack!
+                    if (!prefixMatchFound)
+                        ret = "mscorlib!" + ret;
+                }
             }
             return ret;
         }
@@ -948,6 +951,13 @@ internal ManagedSymbolModule PdbForSourceServer
             }
         }
 
+        /// <summary>
+        /// Decide if we try to get a Project N map that maps $_NN to a pre-merged assembly name.
+        /// This is an exprimental code. Default to true because we don't have this switch when the
+        /// code is initially introduced. Deprecate this when the code is mature enough.
+        /// </summary>
+        internal bool LookupAssemblyNameForCompiledNative { get; set; } = true;
+
         /// <summary>
         /// For Project N modules it returns the list of pre merged IL assemblies and the corresponding mapping.
         /// </summary>
diff --git a/src/TraceEvent/Symbols/SymbolReader.cs b/src/TraceEvent/Symbols/SymbolReader.cs
index 3333ef064..442eeff13 100644
--- a/src/TraceEvent/Symbols/SymbolReader.cs
+++ b/src/TraceEvent/Symbols/SymbolReader.cs
@@ -301,7 +301,7 @@ public ManagedSymbolModule OpenSymbolFile(string pdbFilePath)
                 else
                 {
                     stream.Dispose();
-                    ret = new NativeSymbolModule(this, pdbFilePath);
+                    ret = new NativeSymbolModule(this, pdbFilePath) { LookupAssemblyNameForCompiledNative = this.LookupAssemblyNameForCompiledNative };
                 }
                 m_symbolModuleCache.Add(pdbFilePath, ret);
             }
@@ -403,6 +403,12 @@ public string SourceCacheDirectory
         /// </summary>
         public TextWriter Log { get { return m_log; } }
 
+        /// <summary>
+        /// Sets whether try to look for assembly name for compiled to native assemblies.
+        /// Default to because the code was introduced without this flag.
+        /// </summary>
+        public bool LookupAssemblyNameForCompiledNative { get; set; } = true;
+
         /// <summary>
         /// Given a full filename path to an NGEN image, insure that there is an NGEN image for it
         /// in the symbol cache.  If one already exists, this method simply returns that.   If not
@@ -1382,7 +1388,7 @@ struct PdbSignature : IEquatable<PdbSignature>
         private Cache<PdbSignature, string> m_pdbPathCache;
         private string m_symbolPath;
 
-#endregion
+        #endregion
     }
 
     /// <summary>
@@ -1430,7 +1436,7 @@ public abstract class ManagedSymbolModule
         /// </summary>
         protected virtual string GetSourceLinkJson() { return null; }
 
-#region private 
+        #region private 
 
         protected ManagedSymbolModule(SymbolReader reader, string path) { _pdbPath = path; _reader = reader; }
 
@@ -1513,7 +1519,7 @@ private List<Tuple<string, string>> ParseSourceLinkJson(string sourceLinkJson)
         SymbolReader _reader;
         List<Tuple<string, string>> _sourceLinkMapping;      // Used by SourceLink to map build paths to URLs (see GetUrlForFilePath)
         bool _sourceLinkMappingInited;                       // Lazy init flag. 
-#endregion
+        #endregion
     }
 
     /// <summary>
@@ -1530,7 +1536,7 @@ public class SourceLocation
         /// </summary>
         public int LineNumber { get; private set; }
 
-#region private
+        #region private
         internal SourceLocation(SourceFile sourceFile, int lineNumber)
         {
             // The library seems to see FEEFEE for the 'unknown' line number.  0 seems more intuitive
@@ -1540,7 +1546,7 @@ internal SourceLocation(SourceFile sourceFile, int lineNumber)
             SourceFile = sourceFile;
             LineNumber = lineNumber;
         }
-#endregion
+        #endregion
     }
 
     /// <summary>
@@ -1662,7 +1668,7 @@ public virtual string GetSourceFile(bool requireChecksumMatch = false)
         /// </summary>; 
         public bool ChecksumMatches { get { return _checksumMatches; } }
 
-#region private 
+        #region private 
         protected SourceFile(ManagedSymbolModule symbolModule) { _symbolModule = symbolModule; }
 
         protected TextWriter _log { get { return _symbolModule._log; } }
@@ -1783,7 +1789,7 @@ private static bool ArrayEquals(byte[] bytes1, byte[] bytes2)
         protected string _filePath;
         bool _getSourceCalled;
         bool _checksumMatches;
-#endregion
+        #endregion
     }
 }