Goes with: Improve --datetime accuracy

Author: JeffersonMontgomery-Intel

PresentData/TraceSession.cpp

@@ -481,8 +481,7 @@ ULONG TraceSession::Start(
     PMTraceConsumer* pmConsumer,
     MRTraceConsumer* mrConsumer,
     wchar_t const* etlPath,
-    wchar_t const* sessionName,
-    TimestampType timestampType)
+    wchar_t const* sessionName)
 {
     assert(mSessionHandle == 0);
     assert(mTraceHandle == INVALID_PROCESSTRACE_HANDLE);
@@ -529,7 +528,7 @@ ULONG TraceSession::Start(
 
         TraceProperties sessionProps = {};
         sessionProps.Wnode.BufferSize = (ULONG) sizeof(TraceProperties);
-        sessionProps.Wnode.ClientContext = timestampType;         // Clock resolution to use when logging the timestamp for each event
+        sessionProps.Wnode.ClientContext = mTimestampType;        // Clock resolution to use when logging the timestamp for each event
         sessionProps.LogFileMode = EVENT_TRACE_REAL_TIME_MODE;    // We have a realtime consumer, not writing to a log file
         sessionProps.LogFileNameOffset = 0;                       // 0 means no output log file
         sessionProps.LoggerNameOffset = offsetof(TraceProperties, mSessionName);  // Location of session name; will be written by StartTrace()
@@ -584,7 +583,8 @@ ULONG TraceSession::Start(
     // time of the first event, which matches GPUVIEW usage, and realtime
     // captures are based off the timestamp here.
 
-    switch (traceProps.LogfileHeader.ReservedFlags) {
+    mTimestampType = (TimestampType) traceProps.LogfileHeader.ReservedFlags;
+    switch (mTimestampType) {
     case TIMESTAMP_TYPE_SYSTEM_TIME:
         mTimestampFrequency.QuadPart = 10000000ull;
         break;

PresentData/TraceSession.hpp

@@ -5,27 +5,28 @@ struct PMTraceConsumer;
 struct MRTraceConsumer;
 
 struct TraceSession {
+    enum TimestampType {
+        TIMESTAMP_TYPE_QPC = 1,
+        TIMESTAMP_TYPE_SYSTEM_TIME = 2,
+        TIMESTAMP_TYPE_CPU_CYCLE_COUNTER = 3,
+    };
+
     LARGE_INTEGER mStartTimestamp = {};
     LARGE_INTEGER mTimestampFrequency = {};
     uint64_t mStartFileTime = 0;
+    TimestampType mTimestampType = TIMESTAMP_TYPE_QPC;
+
     PMTraceConsumer* mPMConsumer = nullptr;
     MRTraceConsumer* mMRConsumer = nullptr;
     TRACEHANDLE mSessionHandle = 0;                         // invalid session handles are 0
     TRACEHANDLE mTraceHandle = INVALID_PROCESSTRACE_HANDLE; // invalid trace handles are INVALID_PROCESSTRACE_HANDLE
     ULONG mContinueProcessingBuffers = TRUE;
 
-    enum TimestampType {
-        TIMESTAMP_TYPE_QPC = 1,
-        TIMESTAMP_TYPE_SYSTEM_TIME = 2,
-        TIMESTAMP_TYPE_CPU_CYCLE_COUNTER = 3,
-    };
-
     ULONG Start(
         PMTraceConsumer* pmConsumer,  // Required PMTraceConsumer instance
         MRTraceConsumer* mrConsumer,  // If nullptr, no WinMR tracing
         wchar_t const* etlPath,       // If nullptr, live/realtime tracing session
-        wchar_t const* sessionName,   // Required session name
-        TimestampType timestampType); // Which timestamp type to use
+        wchar_t const* sessionName);  // Required session name
 
     void Stop();
 

PresentMon/TraceSession.cpp

@@ -34,12 +34,17 @@ bool StartTraceSession()
         gMRConsumer = new MRTraceConsumer(args.mTrackDisplay);
     }
 
+    if (args.mOutputDateTime) {
+       gSession.mTimestampType = TraceSession::TIMESTAMP_TYPE_SYSTEM_TIME;
+    } else {
+       gSession.mTimestampType = TraceSession::TIMESTAMP_TYPE_QPC;
+    }
+
     // Start the session;
     // If a session with this same name is already running, we either exit or
     // stop it and start a new session.  This is useful if a previous process
     // failed to properly shut down the session for some reason.
-    auto timestampType = args.mOutputDateTime ? TraceSession::TIMESTAMP_TYPE_SYSTEM_TIME : TraceSession::TIMESTAMP_TYPE_QPC;
-    auto status = gSession.Start(gPMConsumer, gMRConsumer, args.mEtlFileName, args.mSessionName, timestampType);
+    auto status = gSession.Start(gPMConsumer, gMRConsumer, args.mEtlFileName, args.mSessionName);
     if (status == ERROR_ALREADY_EXISTS) {
         if (args.mStopExistingSession) {
             PrintWarning(
@@ -61,7 +66,7 @@ bool StartTraceSession()
 
         status = TraceSession::StopNamedSession(args.mSessionName);
         if (status == ERROR_SUCCESS) {
-            status = gSession.Start(gPMConsumer, gMRConsumer, args.mEtlFileName, args.mSessionName, timestampType);
+            status = gSession.Start(gPMConsumer, gMRConsumer, args.mEtlFileName, args.mSessionName);
         }
     }
 
@@ -164,12 +169,13 @@ double TimestampToSeconds(uint64_t timestamp)
 
 void TimestampToLocalSystemTime(uint64_t timestamp, SYSTEMTIME* st, uint64_t* ns)
 {
-    /* if not TIMESTAMP_TYPE_SYSTEM_TIME
-    auto tns = (timestamp - gSession.mStartTimestamp.QuadPart) * 1000000000ull / gSession.mTimestampFrequency.QuadPart;
-    auto ft = gSession.mStartFileTime + (tns / 100);
-    FileTimeToSystemTime((FILETIME const*) &ft, st);
-    *ns = tns % 1000000000;
-    */
-    FileTimeToSystemTime((FILETIME const*) &timestamp, st);
+    if (gSession.mTimestampType != TraceSession::TIMESTAMP_TYPE_SYSTEM_TIME) {
+        auto delta100ns = (timestamp - gSession.mStartTimestamp.QuadPart) * 10000000ull / gSession.mTimestampFrequency.QuadPart;
+        timestamp = gSession.mStartFileTime + delta100ns;
+    }
+
+    FILETIME lft{};
+    FileTimeToLocalFileTime((FILETIME*) &timestamp, &lft);
+    FileTimeToSystemTime(&lft, st);
     *ns = (timestamp % 10000000) * 100;
 }