telemetry and timing updates

tests/RenderCadenceCompositorFrameExchangeTests.cpp

@@ -27,6 +27,13 @@ SystemFrameExchangeConfig MakeConfig(std::size_t capacity = 2)
 	return config;
 }
 
+SystemFrameExchangeConfig MakeBoundedCompletedConfig(std::size_t capacity = 4, std::size_t maxCompletedFrames = 2)
+{
+	SystemFrameExchangeConfig config = MakeConfig(capacity);
+	config.maxCompletedFrames = maxCompletedFrames;
+	return config;
+}
+
 void TestAcquirePublishesAndSchedules()
 {
 	SystemFrameExchange exchange(MakeConfig(1));
@@ -82,6 +89,31 @@ void TestAcquirePreservesCompletedFrames()
 	Expect(metrics.acquireMisses == 1, "preserving acquire miss is counted");
 }
 
+void TestCompletedReserveIsBoundedFifo()
+{
+	SystemFrameExchange exchange(MakeBoundedCompletedConfig(4, 2));
+
+	for (uint64_t frameIndex = 1; frameIndex <= 3; ++frameIndex)
+	{
+		SystemFrame frame;
+		Expect(exchange.AcquireForRender(frame), "bounded reserve frame can be acquired");
+		frame.frameIndex = frameIndex;
+		Expect(exchange.PublishCompleted(frame), "bounded reserve frame can be completed");
+	}
+
+	SystemFrame firstScheduled;
+	Expect(exchange.ConsumeCompletedForSchedule(firstScheduled), "bounded reserve oldest retained frame can be scheduled");
+	Expect(firstScheduled.frameIndex == 2, "bounded reserve drops oldest overflow and keeps FIFO order");
+
+	SystemFrame secondScheduled;
+	Expect(exchange.ConsumeCompletedForSchedule(secondScheduled), "bounded reserve second retained frame can be scheduled");
+	Expect(secondScheduled.frameIndex == 3, "bounded reserve schedules next retained frame");
+
+	SystemFrameExchangeMetrics metrics = exchange.Metrics();
+	Expect(metrics.completedDrops == 1, "bounded completed reserve records oldest overflow drop");
+	Expect(metrics.scheduledFrames == 2, "bounded reserve schedules retained frames");
+}
+
 void TestScheduledFramesAreNotDropped()
 {
 	SystemFrameExchange exchange(MakeConfig(1));
@@ -177,6 +209,7 @@ int main()
 {
 	TestAcquirePublishesAndSchedules();
 	TestAcquirePreservesCompletedFrames();
+	TestCompletedReserveIsBoundedFifo();
 	TestScheduledFramesAreNotDropped();
 	TestGenerationValidationRejectsStaleFrames();
 	TestPixelFormatAwareSizing();