timing refactor

apps/RenderCadenceCompositor/frames/SystemFrameExchange.cpp

@@ -47,12 +47,9 @@ bool SystemFrameExchange::AcquireForRender(SystemFrame& frame)
 	std::lock_guard<std::mutex> lock(mMutex);
 	if (!AcquireFreeLocked(frame))
 	{
-		if (!DropOldestCompletedLocked() || !AcquireFreeLocked(frame))
-		{
-			frame = SystemFrame();
-			++mCounters.acquireMisses;
-			return false;
-		}
+		frame = SystemFrame();
+		++mCounters.acquireMisses;
+		return false;
 	}
 
 	++mCounters.acquiredFrames;
@@ -234,27 +231,6 @@ bool SystemFrameExchange::AcquireFreeLocked(SystemFrame& frame)
 	return false;
 }
 
-bool SystemFrameExchange::DropOldestCompletedLocked()
-{
-	while (!mCompletedIndices.empty())
-	{
-		const std::size_t index = mCompletedIndices.front();
-		mCompletedIndices.pop_front();
-		if (index >= mSlots.size() || mSlots[index].state != SystemFrameSlotState::Completed)
-			continue;
-
-		Slot& slot = mSlots[index];
-		slot.state = SystemFrameSlotState::Free;
-		slot.frameIndex = 0;
-		++slot.generation;
-		++mCounters.completedDrops;
-		mCondition.notify_all();
-		return true;
-	}
-
-	return false;
-}
-
 bool SystemFrameExchange::IsValidLocked(const SystemFrame& frame) const
 {
 	return frame.index < mSlots.size() && mSlots[frame.index].generation == frame.generation;