diff --git a/stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp b/stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp
index fb53bd7..1fa27c4 100644
--- a/stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp
+++ b/stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp
@@ -29,6 +29,10 @@
 namespace smo {
 namespace stim_buff {
 
+#ifndef SMO_PRINT_PCLOUD_ASSEMBLY_RESULTS
+#define SMO_PRINT_PCLOUD_ASSEMBLY_RESULTS 1
+#endif
+
 inline LivoxProto1DllState& getLivoxProto1State() { return livoxProto1; }
 
 struct DummyLivoxEthHeader
@@ -431,6 +435,29 @@ public:
 		callOriginalCb(success, loop);
 	}
 
+	void logAssemblyCycleResult(
+		const char *outcome, bool callbackSuccess) const
+	{
+#if SMO_PRINT_PCLOUD_ASSEMBLY_RESULTS
+		size_t trackerAssembledCount = 0;
+		for (const auto &slotDesc : engine.assembledSlotsTracker)
+		{
+			if (slotDesc.assembled) {
+				++trackerAssembledCount;
+			}
+		}
+
+		std::cout << "AssembleFrameReq: " << outcome
+			<< " callbackSuccess=" << callbackSuccess
+			<< " timerFired=" << (timerFired.load() ? "yes" : "no")
+			<< " nSucceeded=" << loop.nSucceeded.load()
+			<< " nFailed=" << loop.nFailed.load()
+			<< " nTotal=" << loop.nTotal
+			<< " trackerAssembled=" << trackerAssembledCount
+			<< std::endl;
+#endif
+	}
+
 public:
 	void assembleFrameReq1_posted(
 		std::shared_ptr<AssembleFrameReq> context)
@@ -497,6 +524,8 @@ public:
 		{
 			context->engine.assemblyCycleComplete();
 			context->loop.setRemainingIterationsToFailure();
+			context->logAssemblyCycleResult(
+				"engine_cancelled_on_timer", false);
 			context->callOriginalCallback(false, context->loop);
 			return;
 		}
@@ -516,6 +545,8 @@ public:
 		{
 			context->engine.assemblyCycleComplete();
 			context->loop.setRemainingIterationsToFailure();
+			context->logAssemblyCycleResult(
+				"engine_cancelled_on_cqe", false);
 			context->callOriginalCallback(false, context->loop);
 			return;
 		}
@@ -566,6 +597,7 @@ public:
 		// Error: no slots succeeded - no data received successfully.
 		if (context->loop.nSucceeded.load() == 0)
 		{
+			context->logAssemblyCycleResult("no_slots_succeeded", false);
 			context->callOriginalCallback(false, context->loop);
 			return;
 		}
@@ -598,6 +630,7 @@ public:
 					<< ") > nTotal (" << context->loop.nTotal << ")\n";
 			}
 
+			context->logAssemblyCycleResult("all_slots_succeeded", true);
 			context->callOriginalCallback(true, context->loop);
 			return;
 		}
@@ -605,11 +638,12 @@ public:
 		if (context->loop.nSucceeded.load() < context->loop.nTotal)
 		{
 			// Success: some slots succeeded (less than total)
-			// Note: dummy fill for un-assembled slots will be implemented later
+			context->logAssemblyCycleResult("partial_slots_succeeded", true);
 			context->callOriginalCallback(true, context->loop);
 			return;
 		}
 
+		context->logAssemblyCycleResult("invalid_slot_count_state", false);
 		if (smoHooksPtr->OptionParser_getOptions().verbose)
 		{
 			std::cerr << __func__ << ": Invalid state: nSucceeded ("
diff --git a/stimBuffApis/livoxGen1/openClCollatingAndMeshingEngine.cpp b/stimBuffApis/livoxGen1/openClCollatingAndMeshingEngine.cpp
index 06e8cf8..4083725 100644
--- a/stimBuffApis/livoxGen1/openClCollatingAndMeshingEngine.cpp
+++ b/stimBuffApis/livoxGen1/openClCollatingAndMeshingEngine.cpp
@@ -28,6 +28,10 @@ extern const smo::stim_buff::SmoCallbacks* smoHooksPtr;
 namespace smo {
 namespace stim_buff {
 
+#ifndef SMO_PRINT_PCLOUD_COLLATE_RESULTS
+#define SMO_PRINT_PCLOUD_COLLATE_RESULTS 1
+#endif
+
 OpenClCollatingAndMeshingEngine::OpenClCollatingAndMeshingEngine(
 	PcloudStimulusProducer& parent_)
 : parent(parent_),
@@ -1194,14 +1198,15 @@ OpenClCollatingAndMeshingEngine::compactCollateAndMeshFrameCReq(
 		}
 		(void)highIntensityCount;
 
-#if 0
-		std::cout << __func__ << ": intensityRingBufferIndex="
+#if SMO_PRINT_PCLOUD_COLLATE_RESULTS
+		std::cout << __func__ << ": collate done intensityRingBufferIndex="
 			<< (intensityStimFrame.has_value() ?
 				intensityStimFrame->get().ringBufferIndex : SIZE_MAX)
-			<< ", pointsPerDgram=" << pointsPerDgram
-			<< ", nSucceeded=" << nSucceeded
-			<< ", totalPoints=" << totalPoints
-			<< ", highIntensityCount=" << highIntensityCount << std::endl;
+			<< " pointsPerDgram=" << pointsPerDgram
+			<< " nSucceeded=" << nSucceeded
+			<< " totalPoints=" << totalPoints
+			<< " highIntensityCount=" << highIntensityCount
+			<< std::endl;
 #endif
 
 		co_return success;