[idd] rgb24: isolate benchmark samples from cadence

Run effect timing samples only when the retained candidate pipeline is idle
and force each completed sample to publish immediately. This prevents work
from superseded candidates from being charged to a surviving sample.

Include the indirect CPU copy to IVSHMEM in the measured copy stage while
preserving the wall-clock fallback when GPU timestamps are unavailable.

idd/LGIdd/CSwapChainProcessor.cpp

@@ -552,6 +552,7 @@ void CSwapChainProcessor::CandidateCompletionFunction(
   uint64_t gpuEnd   = 0;
   const bool timingValid = result && slot->GetGPUTimes(gpuStart, gpuEnd);
 
+  bool forceFrame = false;
   AcquireSRWLockExclusive(&sc->m_candidateLock);
   if (candidate->state == CANDIDATE_PREPARING)
   {
@@ -559,7 +560,9 @@ void CSwapChainProcessor::CandidateCompletionFunction(
     candidate->prepareGPUStart    = gpuStart;
     candidate->prepareGPUEnd      = gpuEnd;
     candidate->prepareTimingValid = timingValid;
-    candidate->state = result ? CANDIDATE_READY : CANDIDATE_FREE;
+    candidate->state              =
+      result ? CANDIDATE_READY : CANDIDATE_FREE;
+    forceFrame = result && candidate->timingToken != 0;
   }
   ReleaseSRWLockExclusive(&sc->m_candidateLock);
 
@@ -568,6 +571,8 @@ void CSwapChainProcessor::CandidateCompletionFunction(
     sc->SetFullPendingDamage();
     sc->m_devContext->ForceFrame();
   }
+  else if (forceFrame)
+    sc->m_devContext->ForceFrame();
   sc->SignalCandidateState();
 }
 
@@ -606,10 +611,16 @@ void CSwapChainProcessor::CompletionFunction(
   const uint64_t publishStart = fbRes->GetCopyStart();
   uint64_t       gpuCopyStart     = 0;
   uint64_t       gpuCopyEnd       = 0;
-
+  uint64_t       indirectCopyTime = 0;
   if (sc->m_dx12Device->IsIndirectCopy())
+  {
+    // GPU timestamps end at the readback copy. Include the following CPU copy
+    // to IVSHMEM in effect benchmark samples without charging it to Ready.
+    const uint64_t indirectCopyStart = CFrameScheduler::Nanotime();
     sc->m_devContext->WriteFrameBuffer(
       fbRes->GetFrameIndex(), fbRes->GetMap(), 0, fbRes->GetFrameSize(), false);
+    indirectCopyTime = CFrameScheduler::Nanotime() - indirectCopyStart;
+  }
 
   // Queue waits execute before the start timestamp. The end timestamp follows
   // the last copy command, separating GPU work from readiness dispatch.
@@ -634,7 +645,7 @@ void CSwapChainProcessor::CompletionFunction(
   uint64_t publishCopyTime = readyEnd - publishStart;
   if (gpuTimingValid && gpuCopyStart >= publishStart &&
       gpuCopyEnd >= gpuCopyStart && gpuCopyEnd <= readyEnd)
-    publishCopyTime = gpuCopyEnd - gpuCopyStart;
+    publishCopyTime = gpuCopyEnd - gpuCopyStart + indirectCopyTime;
 
   const uint64_t copyTime = prepareCopyTime + publishCopyTime;
   const uint64_t elapsed  = readyEnd - postProcessStart;
@@ -837,7 +848,7 @@ void CSwapChainProcessor::AccumulateFrameDamage(
   ReleaseSRWLockExclusive(&m_damageLock);
 }
 
-int CSwapChainProcessor::AcquireCandidate()
+int CSwapChainProcessor::AcquireCandidate(bool exclusiveSample)
 {
   HANDLE waitHandles[] =
   {
@@ -850,21 +861,28 @@ int CSwapChainProcessor::AcquireCandidate()
     int      selected   = -1;
     uint64_t oldest     = UINT64_MAX;
     bool     superseded = false;
+    bool     idle       = true;
 
     AcquireSRWLockExclusive(&m_candidateLock);
     for (unsigned i = 0; i < ARRAYSIZE(m_candidates); ++i)
-      if (m_candidates[i].state == CANDIDATE_FREE)
+      if (m_candidates[i].state != CANDIDATE_FREE)
+        idle = false;
+      else if (selected < 0)
       {
         selected = static_cast<int>(i);
-        break;
       }
 
+    // Effect timing samples must not queue behind work which can later be
+    // superseded, otherwise that discarded work contaminates the sample.
+    if (exclusiveSample && !idle)
+      selected = -1;
+
     unsigned readyCount = 0;
     for (const FrameCandidate& candidate : m_candidates)
       if (candidate.state == CANDIDATE_READY)
         ++readyCount;
 
-    if (selected < 0 && readyCount > 1)
+    if (!exclusiveSample && selected < 0 && readyCount > 1)
       for (unsigned i = 0; i < ARRAYSIZE(m_candidates); ++i)
         if (m_candidates[i].state == CANDIDATE_READY &&
             m_candidates[i].sequence < oldest)
@@ -1428,6 +1446,8 @@ bool CSwapChainProcessor::SwapChainNewFrame(ComPtr<IDXGIResource> acquiredBuffer
   bool needsReconfigure         = false;
   bool postProcessFormatChanged = false;
   bool requiresFullDamage       = false;
+  unsigned timingEffectIndex    = 0;
+  uint64_t timingToken          = 0;
   {
     CSRWExclusiveLock pipelineLock(&m_pipelineLock);
     m_postProcessors[0].Update(srcFormat);
@@ -1500,6 +1520,9 @@ bool CSwapChainProcessor::SwapChainNewFrame(ComPtr<IDXGIResource> acquiredBuffer
     requiresFullDamage = m_postProcessors[0].RequiresFullDamage();
     if (requiresFullDamage)
       SetFullPendingDamage();
+
+    m_postProcessors[0].GetTimingToken(
+      &timingEffectIndex, &timingToken);
   }
 
   if (needsReconfigure || postProcessFormatChanged || frameMetadataChanged)
@@ -1514,7 +1537,7 @@ bool CSwapChainProcessor::SwapChainNewFrame(ComPtr<IDXGIResource> acquiredBuffer
       return true;
   }
 
-  const int selectedCandidate = AcquireCandidate();
+  const int selectedCandidate = AcquireCandidate(timingToken != 0);
   if (selectedCandidate < 0)
   {
     m_devContext->FrameSuperseded();
@@ -1645,8 +1668,8 @@ bool CSwapChainProcessor::SwapChainNewFrame(ComPtr<IDXGIResource> acquiredBuffer
   if (nbDirtyRects)
     memcpy(candidate.dirtyRects, currentDirtyRects,
       nbDirtyRects * sizeof(*candidate.dirtyRects));
-  postProcessor.GetTimingToken(
+  candidate.timingEffectIndex = timingEffectIndex;
-    &candidate.timingEffectIndex, &candidate.timingToken);
+  candidate.timingToken       = timingToken;
 
   copySlot->SetCompletionCallback(
     &CandidateCompletionFunction, this, &candidate);

idd/LGIdd/CSwapChainProcessor.h

@@ -137,7 +137,7 @@ private:
     const CFrameScheduler::Schedule& schedule, bool periodic,
     uint64_t publishStart);
   bool HasReadyCandidate();
-  int AcquireCandidate();
+  int AcquireCandidate(bool exclusiveSample);
   void ReleaseCandidate(unsigned candidateIndex);
   bool EnsureCandidateResource(unsigned candidateIndex,
     ID3D12Resource * source);