LivoxGen1: Use syncCancelerForAsyncWork in producer pipeline

commonLibs/attachmentSupport/stimulusProducer.cpp

@@ -8,7 +8,6 @@
 #include <boost/system/error_code.hpp>
 #include <opts.h>
 #include <componentThread.h>
-#include <spinscale/spinLock.h>
 #include <user/stimulusProducer.h>
 #include <user/stimulusBuffer.h>
 
@@ -91,10 +90,7 @@ void StimulusProducer::destroyAttachedStimulusBuffer(
 
 void StimulusProducer::stop()
 {
-	{
+	(void)stimulusProducerCanceler.requestStop();
-		sscl::SpinLock::Guard lock(shouldContinueLock);
-		shouldContinue = false;
-	}
 
 	// Cancel timer immediately
 	timer.cancel();
@@ -105,7 +101,7 @@ void StimulusProducer::stop()
 
 void StimulusProducer::scheduleNextTimeout(int delayMs)
 {
-	if (!shouldContinue)
+	if (stimulusProducerCanceler.isCancellationRequestedUnlocked())
 		{ return; }
 
 	// Schedule the next timeout using the provided delay
@@ -131,10 +127,6 @@ void StimulusProducer::onTimeout(const boost::system::error_code& error)
 		return;
 	}
 
-	sscl::SpinLock::Guard lock(shouldContinueLock);
-	if (!shouldContinue)
-		{ return; }
-
 	/**	EXPLANATION:
 	 * We need to ensure that there's only ever one stimframe being produced
 	 * during any CONFIG_STIMBUFF_FRAME_PERIOD_MS period. To guarantee this, we
@@ -148,35 +140,39 @@ void StimulusProducer::onTimeout(const boost::system::error_code& error)
 	 */
 	int nextWakeupDelayMs;
 	bool deferred = false;
-	if (frameAssemblyRateLimiter.tryAcquire())
+	bool shouldContinue;
+	shouldContinue = stimulusProducerCanceler.execUncancelableSegmentOrAbort(
+		[&]()
 	{
-		nextWakeupDelayMs = CONFIG_STIMBUFF_FRAME_PERIOD_MS;
+		if (frameAssemblyRateLimiter.tryAcquire())
-
-		// Check if we're ending a deferral period
-		if (nDeferrals > 0)
 		{
-			auto deferralEndTime = std::chrono::high_resolution_clock::now();
+			nextWakeupDelayMs = CONFIG_STIMBUFF_FRAME_PERIOD_MS;
-			auto duration = deferralEndTime - deferralStartTime;
-			auto durationMs = std::chrono::duration_cast<
-				std::chrono::milliseconds>(duration);
 
-			std::cout << __func__ << ": Deferral period ended. "
+			// Check if we're ending a deferral period
-				<< "Total deferrals: " << nDeferrals
+			if (nDeferrals > 0)
-				<< ", Duration: " << durationMs.count() << "ms" << std::endl;
+			{
+				auto deferralEndTime = std::chrono::high_resolution_clock::now();
+				auto duration = deferralEndTime - deferralStartTime;
+				auto durationMs = std::chrono::duration_cast<
+					std::chrono::milliseconds>(duration);
 
-			nDeferrals = 0;
+				std::cout << __func__ << ": Deferral period ended. "
+					<< "Total deferrals: " << nDeferrals
+					<< ", Duration: " << durationMs.count() << "ms" << std::endl;
+
+				nDeferrals = 0;
+			}
+
+			/**	EXPLANATION:
+			 * Call the derived class's frame production handler
+			 * Note: The derived class's frame production handler (aka
+			 * its implementation of stimFrameProductionTimesliceInd()) must
+			 * release the lock when frame production completes
+			 */
+			stimFrameProductionTimesliceInd();
+			return;
 		}
 
-		/**	EXPLANATION:
-		 * Call the derived class's frame production handler
-		 * Note: The derived class's frame production handler (aka
-		 * its implementation of stimFrameProductionTimesliceInd()) must
-		 * release the lock when frame production completes
-		 */
-		stimFrameProductionTimesliceInd();
-	}
-	else
-	{
 		nextWakeupDelayMs = CONFIG_STIMBUFF_FRAME_RETRY_DELAY_MS;
 		deferred = true;
 
@@ -189,7 +185,9 @@ void StimulusProducer::onTimeout(const boost::system::error_code& error)
 				"Configured deferral period: " << nextWakeupDelayMs << "ms"
 				<< std::endl;
 		}
-	}
+	});
+
+	if (!shouldContinue) { return; }
 
 	scheduleNextTimeout(nextWakeupDelayMs);
 

include/user/stimulusProducer.h

@@ -14,6 +14,7 @@
 #include <boost/asio/io_service.hpp>
 #include <boost/asio/deadline_timer.hpp>
 #include <spinscale/spinLock.h>
+#include <spinscale/syncCancelerForAsyncWork.h>
 #include "deviceAttachmentSpec.h"
 
 namespace smo {
@@ -40,8 +41,7 @@ public:
 			&deviceAttachmentSpec,
 		boost::asio::io_service& ioService_)
 	: deviceAttachmentSpec(deviceAttachmentSpec),
-	ioService(ioService_),
+	ioService(ioService_), timer(ioService),
-	shouldContinue(false), timer(ioService),
 	nDeferrals(0)
 	{}
 
@@ -59,7 +59,7 @@ public:
 		std::cout << __func__ << ": Starting stimulus producer for device "
 			<< deviceAttachmentSpec->deviceSelector << std::endl;
 
-		shouldContinue = true;
+		stimulusProducerCanceler.startAcceptingWork();
 		nDeferrals = 0;
 		scheduleNextTimeout();
 	}
@@ -109,8 +109,7 @@ public:
 private:
 	boost::asio::io_service& ioService;
 protected:
-	sscl::SpinLock shouldContinueLock;
+	sscl::SyncCancelerForAsyncWork stimulusProducerCanceler;
-	bool shouldContinue;
 private:
 	boost::asio::deadline_timer timer;
 	size_t nDeferrals;

stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp

@@ -22,7 +22,6 @@
 #include <spinscale/cps/asynchronousBridge.h>
 #include <spinscale/cps/callback.h>
 #include <spinscale/cps/callableTracer.h>
-#include <spinscale/spinLock.h>
 #include "ioUringAssemblyEngine.h"
 #include "pcloudStimulusProducer.h"
 #include "livoxGen1.h"
@@ -59,7 +58,6 @@ IoUringAssemblyEngine::IoUringAssemblyEngine(
 frameAssemblyDesc(nullptr), ring{},
 eventfdFd(-1), eventfdDesc(nullptr), eventfd_value(0),
 stallTimer(parent_.device->componentThread->getIoService()),
-shouldAcceptRequests(false),
 nDgramsPerStagingBufferFrame(nDgramsPerStagingBufferFrame_),
 assembledSlotsTracker(nDgramsPerStagingBufferFrame_),
 randomDevice(), randomGenerator(randomDevice())
@@ -68,13 +66,10 @@ randomDevice(), randomGenerator(randomDevice())
 bool IoUringAssemblyEngine::setup()
 {
 	// Defensive check to prevent double-calling
+	if (!ioUringAssemblyEngnCanceler.isCancellationRequested())
 	{
-		sscl::SpinLock::Guard lock(shouldAcceptRequestsLock);
+		throw std::runtime_error(std::string(__func__) + ": setup() called "
-		if (shouldAcceptRequests)
+			"while already set up");
-		{
-			throw std::runtime_error(std::string(__func__) + ": setup() called "
-				"while already set up");
-		}
 	}
 
 	// Get FrameAssemblyDesc from staging buffer
@@ -156,7 +151,7 @@ bool IoUringAssemblyEngine::setup()
 	if (ret < 0)
 		{ goto cleanup_eventfd; }
 
-	shouldAcceptRequests = true;
+	ioUringAssemblyEngnCanceler.startAcceptingWork();
 	return true;
 
 cleanup_eventfd:
@@ -229,7 +224,7 @@ void IoUringAssemblyEngine::resetAndAssembleFrame(
 			+ ": onCqeReady callback is invalid");
 	}
 
-	if (!shouldAcceptRequests)
+	if (ioUringAssemblyEngnCanceler.isCancellationRequestedUnlocked())
 	{
 		throw std::runtime_error(std::string(__func__)
 			+ ": engine is not accepting requests");
@@ -321,11 +316,7 @@ void IoUringAssemblyEngine::resetAndAssembleFrame(
 
 bool IoUringAssemblyEngine::stop()
 {
-	// Acquire and release lock tightly around setting the flag
+	return ioUringAssemblyEngnCanceler.requestStop();
-	sscl::SpinLock::Guard lock(shouldAcceptRequestsLock);
-	bool wasAcceptingRequests = shouldAcceptRequests;
-	shouldAcceptRequests = false;
-	return wasAcceptingRequests;
 }
 
 void IoUringAssemblyEngine::assemblyCycleComplete()
@@ -444,39 +435,44 @@ public:
 	void assembleFrameReq1_posted(
 		std::shared_ptr<AssembleFrameReq> context)
 	{
-		sscl::SpinLock::Guard lock(engine.shouldAcceptRequestsLock);
+		auto& canceler = engine.ioUringAssemblyEngnCanceler;
+		const bool started = canceler.execUncancelableSegmentOrAbort(
+			[context, this]()
+		{
+			// Initialize loop with number of slots
+			context->loop = sscl::AsynchronousLoop(
+				engine.frameAssemblyDesc->numSlots);
 
-		if (!engine.shouldAcceptRequests)
+			// Record assembly start time
+			engine.assemblyStartTime =
+				std::chrono::high_resolution_clock::now();
+
+			/**	FIXME:
+			 * I'm suspicious of this std::bind return object here. What if us
+			 * setting it to null inside of stop() doesn't actually cause the
+			 * object to be destroyed? This would cause this contin's sh_ptr's
+			 * reference count to never reach 0, causing a memory leak.
+			 */
+			engine.resetAndAssembleFrame(
+				std::bind(&AssembleFrameReq::assembleFrameReq2_2,
+					context.get(), context,
+					std::placeholders::_1, std::placeholders::_2));
+
+			// Set up timeout timer for IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS ms
+			engine.stallTimer.expires_from_now(
+				boost::posix_time::milliseconds(
+					IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS));
+			engine.stallTimer.async_wait(
+				std::bind(&AssembleFrameReq::assembleFrameReq2_1,
+					context.get(), context,
+					std::placeholders::_1));
+		});
+
+		if (!started)
 		{
 			context->callOriginalCallback(false, sscl::AsynchronousLoop(0));
 			return;
 		}
-
-		// Initialize loop with number of slots
-		context->loop = sscl::AsynchronousLoop(engine.frameAssemblyDesc->numSlots);
-
-		// Record assembly start time
-		engine.assemblyStartTime = std::chrono::high_resolution_clock::now();
-
-		/**	FIXME:
-		 * I'm suspicious of this std::bind return object here. What if us
-		 * setting it to null inside of stop() doesn't actually cause the
-		 * object to be destroyed? This would cause this contin's sh_ptr's
-		 * reference count to never reach 0, causing a memory leak.
-		 */
-		engine.resetAndAssembleFrame(
-			std::bind(&AssembleFrameReq::assembleFrameReq2_2,
-				context.get(), context,
-				std::placeholders::_1, std::placeholders::_2));
-
-		// Set up timeout timer for IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS ms
-		engine.stallTimer.expires_from_now(
-			boost::posix_time::milliseconds(
-				IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS));
-		engine.stallTimer.async_wait(
-			std::bind(&AssembleFrameReq::assembleFrameReq2_1,
-				context.get(), context,
-				std::placeholders::_1));
 	}
 
 	void assembleFrameReq2_1(
@@ -498,19 +494,22 @@ public:
 		 * indeed seen a SEGFAULT even in the current code with locking, so
 		 * I'm going to hold the lock here for now.
 		 */
-		sscl::SpinLock::Guard lock(context->engine.shouldAcceptRequestsLock);
+		auto& canceler = context->engine.ioUringAssemblyEngnCanceler;
+		const bool shouldContinue = canceler.execUncancelableSegmentOrAbort(
+			[context]()
+		{
+			// Set timer fired flag
+			context->timerFired.store(true);
+			context->assembleFrameReq3(context);
+		});
 
-		if (!context->engine.shouldAcceptRequests)
+		if (!shouldContinue)
 		{
 			context->engine.assemblyCycleComplete();
 			context->loop.setRemainingIterationsToFailure();
 			context->callOriginalCallback(false, context->loop);
 			return;
 		}
-
-		// Set timer fired flag
-		context->timerFired.store(true);
-		context->assembleFrameReq3(context);
 	}
 
 	void assembleFrameReq2_2(
@@ -518,7 +517,8 @@ public:
 		void *user_data, int cqe_result)
 	{
 		// NB: The lock was acquired by onEventFdRead before calling this func
-		if (!context->engine.shouldAcceptRequests)
+		if (context->engine.ioUringAssemblyEngnCanceler
+			.isCancellationRequestedUnlocked())
 		{
 			context->engine.assemblyCycleComplete();
 			context->loop.setRemainingIterationsToFailure();
@@ -549,8 +549,8 @@ public:
 	{
 		/**	EXPLANATION:
 		 * All branch paths that invoke this unifyig oracle function are
-		 * expected to already hold the shouldAcceptRequestsLock before calling
+		 * expected to already hold ioUringAssemblyEngnCanceler's lock before
-		 * it.
+		 * calling it.
 		 */
 		// Ensure we only execute once using atomic exchange
 		if (context->handlerExecuted.exchange(true)) { return; }
@@ -638,8 +638,7 @@ void IoUringAssemblyEngine::assembleFrameReq(
 	sscl::cps::Callback<assembleFrameReqCbFn> cb)
 {
 	{
-		sscl::SpinLock::Guard lock(shouldAcceptRequestsLock);
+		if (ioUringAssemblyEngnCanceler.isCancellationRequested())
-		if (!shouldAcceptRequests)
 		{
 			cb.callbackFn(false, sscl::AsynchronousLoop(0));
 			return;
@@ -670,7 +669,7 @@ void IoUringAssemblyEngine::onEventfdRead(
 	 * IoUringAssemblyEngine's per-assembly state isn't destroyed while this
 	 * handler is running.
 	 */
-	sscl::SpinLock::Guard lock(shouldAcceptRequestsLock);
+	sscl::SpinLock::Guard lock(ioUringAssemblyEngnCanceler.s.lock);
 	/**	EXPLANATION:
 	 * You'd think we should put check for shouldAcceptRequests here and
 	 * `return` here if !shouldAcceptRequests, but we shouldn't because
@@ -722,7 +721,7 @@ void IoUringAssemblyEngine::onEventfdRead(
 	 * But we do put a `return` here because we know that at this point, the
 	 * caller's callback has already been invoked.
 	 */
-	if (!shouldAcceptRequests
+	if (ioUringAssemblyEngnCanceler.isCancellationRequestedUnlocked()
 		|| eventfdDesc == nullptr || !eventfdDesc->is_open())
 	{
 		return;

stimBuffApis/livoxGen1/ioUringAssemblyEngine.h

@@ -19,7 +19,7 @@
 #include <spinscale/cps/asynchronousContinuation.h>
 #include <spinscale/asynchronousLoop.h>
 #include <spinscale/cps/callback.h>
-#include <spinscale/spinLock.h>
+#include <spinscale/syncCancelerForAsyncWork.h>
 #include <user/frameAssemblyDesc.h>
 #include <user/stagingBuffer.h>
 
@@ -80,12 +80,7 @@ private:
 	boost::asio::deadline_timer stallTimer;
 	// Callback for CQE ntfns (called with user_data+result from each CQE)
 	resetAndAssembleFrameCbFn onCqeReadyCallback;
-	/**	EXPLANATION:
+	sscl::SyncCancelerForAsyncWork ioUringAssemblyEngnCanceler;
-	 * Flag to indicate whether engine should accept new requests.
-	 * Set by setup(), cleared by stop().
-	 */
-	sscl::SpinLock shouldAcceptRequestsLock;
-	bool shouldAcceptRequests;
 
 	size_t nDgramsPerStagingBufferFrame;
 

stimBuffApis/livoxGen1/openClCollatingAndMeshingEngine.cpp

@@ -39,7 +39,6 @@ clAverageIntensityBufferClBuffer(nullptr),
 clAssemblyBuffer(nullptr),
 clCollationBuffer(nullptr),
 clAverageIntensityBuffer(nullptr),
-shouldAcceptRequests(false),
 compactIsRunning(false),
 collateIsRunning(false),
 currentCompactKernelEvent(nullptr), currentCollateKernelEvent(nullptr),
@@ -64,13 +63,10 @@ OpenClCollatingAndMeshingEngine::~OpenClCollatingAndMeshingEngine()
 bool OpenClCollatingAndMeshingEngine::setup()
 {
 	// Defensive check to prevent double-calling
+	if (!openClCollMeshEngnCanceler.isCancellationRequested())
 	{
-		sscl::SpinLock::Guard lock(shouldAcceptRequestsLock);
+		throw std::runtime_error(std::string(__func__) + ": setup() called "
-		if (shouldAcceptRequests)
+			"while already set up");
-		{
-			throw std::runtime_error(std::string(__func__) + ": setup() called "
-				"while already set up");
-		}
 	}
 
 	if (!smoHooksPtr || !smoHooksPtr->ComputeManager_getDevice)
@@ -202,7 +198,7 @@ bool OpenClCollatingAndMeshingEngine::setup()
 
 	clFlush(computeDevice->commandQueue);
 	clFinish(computeDevice->commandQueue);
-	shouldAcceptRequests = true;
+	openClCollMeshEngnCanceler.startAcceptingWork();
 	return true;
 }
 
@@ -771,11 +767,7 @@ bool OpenClCollatingAndMeshingEngine::setupCollateDgramsArgs(
 
 bool OpenClCollatingAndMeshingEngine::stop()
 {
-	// Acquire and release lock tightly around setting the flag
+	return openClCollMeshEngnCanceler.requestStop();
-	sscl::SpinLock::Guard lock(shouldAcceptRequestsLock);
-	bool wasAcceptingRequests = shouldAcceptRequests;
-	shouldAcceptRequests = false;
-	return wasAcceptingRequests;
 }
 
 void OpenClCollatingAndMeshingEngine::compactKernelComplete(bool isFinalizing)
@@ -1051,28 +1043,33 @@ public:
 	void compactCollateAndMeshFrameReq1_doCompact_posted(
 		std::shared_ptr<CompactCollateAndMeshFrameReq> context)
 	{
-		sscl::SpinLock::Guard lock(engine.shouldAcceptRequestsLock);
+		auto& canceler = engine.openClCollMeshEngnCanceler;
-		if (!engine.shouldAcceptRequests)
+		const bool shouldContinue = canceler.execUncancelableSegmentOrAbort(
+			[context, this]()
 		{
-			callOriginalCallback(false);
+			// Record compact kernel start time
-			return;
+			engine.compactKernelStartTime =
-		}
+				std::chrono::high_resolution_clock::now();
 
-		// Record compact kernel start time
+			bool success = engine.startCompactKernel(
-		engine.compactKernelStartTime = std::chrono::high_resolution_clock::now();
+				engine.parent.assemblyBuffer,
+				static_cast<uint32_t>(
+					context->frameAssemblyResult.nSucceeded.load()),
+				std::bind(
+					&CompactCollateAndMeshFrameReq
+						::compactCollateAndMeshFrameReq2_compactDone_posted,
+					context.get(), context,
+					std::placeholders::_1));
 
-		bool success = engine.startCompactKernel(
+			if (!success)
-			engine.parent.assemblyBuffer,
+			{
-			static_cast<uint32_t>(context->frameAssemblyResult.nSucceeded.load()),
+				engine.compactKernelComplete();
-			std::bind(
+				callOriginalCallback(false);
-				&CompactCollateAndMeshFrameReq
+			}
-					::compactCollateAndMeshFrameReq2_compactDone_posted,
+		});
-				context.get(), context,
-				std::placeholders::_1));
 
-		if (!success)
+		if (!shouldContinue)
 		{
-			engine.compactKernelComplete();
 			callOriginalCallback(false);
 			return;
 		}
@@ -1082,8 +1079,27 @@ public:
 		std::shared_ptr<CompactCollateAndMeshFrameReq> context,
 		cl_int compactStatus)
 	{
-		sscl::SpinLock::Guard lock(engine.shouldAcceptRequestsLock);
+		bool compactFailed = false;
-		if (!engine.shouldAcceptRequests)
+
+		auto& canceler = engine.openClCollMeshEngnCanceler;
+		const bool shouldContinue = canceler.execUncancelableSegmentOrAbort(
+			[context, this, compactStatus, &compactFailed]()
+		{
+			engine.compactKernelComplete();
+			// Record compact kernel end time
+			engine.compactKernelEndTime =
+				std::chrono::high_resolution_clock::now();
+
+			// If compact failed, call callback directly with failure
+			if (compactStatus != CL_SUCCESS)
+			{
+				compactFailed = true;
+				callOriginalCallback(false);
+				return;
+			}
+		});
+
+		if (!shouldContinue)
 		{
 			/**	EXPLANATION:
 			 * We intentionally don't call compactKernelComplete() here because
@@ -1095,16 +1111,7 @@ public:
 			return;
 		}
 
-		engine.compactKernelComplete();
+		if (compactFailed) { return; }
-		// Record compact kernel end time
-		engine.compactKernelEndTime = std::chrono::high_resolution_clock::now();
-
-		// If compact failed, call callback directly with failure
-		if (compactStatus != CL_SUCCESS)
-		{
-			callOriginalCallback(false);
-			return;
-		}
 
 #if 0
 		// Print first 4 bytes of each slot
@@ -1116,36 +1123,39 @@ public:
 		}
 #endif
 
-		lock.unlockPrematurely();
 		context->compactCollateAndMeshFrameReq3_doCollate_posted(context);
 	}
 
 	void compactCollateAndMeshFrameReq3_doCollate_posted(
 		std::shared_ptr<CompactCollateAndMeshFrameReq> context)
 	{
-		sscl::SpinLock::Guard lock(engine.shouldAcceptRequestsLock);
+		auto& canceler = engine.openClCollMeshEngnCanceler;
-		if (!engine.shouldAcceptRequests)
+		const bool shouldContinue = canceler.execUncancelableSegmentOrAbort(
+			[context, this]()
 		{
-			callOriginalCallback(false);
+			// Record collate kernel start time
-			return;
+			engine.collateKernelStartTime =
-		}
+				std::chrono::high_resolution_clock::now();
 
-		// Record collate kernel start time
+			bool success = engine.startCollateKernel(
-		engine.collateKernelStartTime = std::chrono::high_resolution_clock::now();
+				context->intensityStimFrame, context->anyAmbienceAttached(),
+				std::bind(
+					&CompactCollateAndMeshFrameReq
+						::compactCollateAndMeshFrameReq4_collateDone_maybePosted,
+					context.get(), context,
+					std::placeholders::_1));
 
-		bool success = engine.startCollateKernel(
+			if (!success)
-			context->intensityStimFrame, context->anyAmbienceAttached(),
+			{
-			std::bind(
+				engine.collateKernelComplete(
-				&CompactCollateAndMeshFrameReq
+					context->intensityStimFrame, context->anyAmbienceAttached());
-					::compactCollateAndMeshFrameReq4_collateDone_maybePosted,
-				context.get(), context,
-				std::placeholders::_1));
 
-		if (!success)
+				callOriginalCallback(false);
+			}
+		});
+
+		if (!shouldContinue)
 		{
-			engine.collateKernelComplete(
-				context->intensityStimFrame, context->anyAmbienceAttached());
-
 			callOriginalCallback(false);
 			return;
 		}
@@ -1155,16 +1165,6 @@ public:
 		[[maybe_unused]] std::shared_ptr<CompactCollateAndMeshFrameReq> context,
 		cl_int collateStatus)
 	{
-		sscl::SpinLock::Guard lock(engine.shouldAcceptRequestsLock);
-		if (!engine.shouldAcceptRequests)
-		{
-			/* We intentionally don't call collateKernelComplete() here for the
-			 * same reason as above.
-			 */
-			callOriginalCallback(false);
-			return;
-		}
-
 		/**	EXPLANATION:
 		 * The reason we don't call collateKernelComplete before checking
 		 * shouldAcceptRequests is because if shouldAcceptRequests is false, then
@@ -1174,77 +1174,92 @@ public:
 		 * Therefore it's finalize()'s responsibility to ensure that it properly
 		 * completes/cleans up any in-flight operations.
 		 */
-		engine.collateKernelComplete(
+		auto& canceler = engine.openClCollMeshEngnCanceler;
-			context->intensityStimFrame, context->anyAmbienceAttached());
+		const bool shouldContinue = canceler.execUncancelableSegmentOrAbort(
-
+			[context, this, collateStatus]()
-		// Produce each attached ambience stimbuff's passband count from
-		// the per-slot averages the collate kernel staged.
-		uint32_t nSucceededForAmbience =
-			context->frameAssemblyResult.nSucceeded.load();
-
-		if (context->lightAmbienceProductionDesc.has_value())
 		{
-			engine.produceAmbienceStimulusFrame(
+			engine.collateKernelComplete(
-				context->lightAmbienceProductionDesc->frame.get(),
+				context->intensityStimFrame, context->anyAmbienceAttached());
-				context->lightAmbienceProductionDesc->comparator,
-				nSucceededForAmbience);
-		}
 
-		if (context->darkAmbienceProductionDesc.has_value())
+			// Produce each attached ambience stimbuff's passband count from
-		{
+			// the per-slot averages the collate kernel staged.
-			engine.produceAmbienceStimulusFrame(
+			uint32_t nSucceededForAmbience =
-				context->darkAmbienceProductionDesc->frame.get(),
+				context->frameAssemblyResult.nSucceeded.load();
-				context->darkAmbienceProductionDesc->comparator,
+
-				nSucceededForAmbience);
+			if (context->lightAmbienceProductionDesc.has_value())
-		}
+			{
-
+				engine.produceAmbienceStimulusFrame(
-		// Record collate kernel end time
+					context->lightAmbienceProductionDesc->frame.get(),
-		engine.collateKernelEndTime = std::chrono::high_resolution_clock::now();
+					context->lightAmbienceProductionDesc->comparator,
-
+					nSucceededForAmbience);
-		bool success = (collateStatus == CL_SUCCESS);
+			}
-
+
-		// Early callback + return pattern
+			if (context->darkAmbienceProductionDesc.has_value())
-		if (!success)
+			{
+				engine.produceAmbienceStimulusFrame(
+					context->darkAmbienceProductionDesc->frame.get(),
+					context->darkAmbienceProductionDesc->comparator,
+					nSucceededForAmbience);
+			}
+
+			// Record collate kernel end time
+			engine.collateKernelEndTime =
+				std::chrono::high_resolution_clock::now();
+
+			bool success = (collateStatus == CL_SUCCESS);
+
+			// Early callback + return pattern
+			if (!success)
+			{
+				callOriginalCallback(false);
+				return;
+			}
+
+			uint32_t nSucceeded = context->frameAssemblyResult.nSucceeded.load();
+
+			int returnMode = static_cast<int>(engine.parent.device->currentReturnMode);
+			size_t pointsPerDgram = livoxProto1::Device::getNPointsPerDgram(
+				returnMode);
+			size_t totalPoints = nSucceeded * pointsPerDgram;
+
+			// Count points with intensity greater than 116
+			size_t highIntensityCount = 0;
+			if (context->intensityStimFrame.has_value())
+			{
+				StimulusFrame& intensityFrame = context->intensityStimFrame->get();
+				float* intensityFloats = reinterpret_cast<float*>(intensityFrame.slotDesc.vaddr);
+				for (size_t i = 0; i < totalPoints; ++i)
+				{
+					float intensity = intensityFloats[i];
+					if (intensity >= 116.0f)
+					{
+						++highIntensityCount;
+					}
+				}
+			}
+			(void)highIntensityCount;
+
+	#if 0
+			std::cout << __func__ << ": intensityRingBufferIndex="
+				<< (context->intensityStimFrame.has_value() ?
+					context->intensityStimFrame->get().ringBufferIndex : SIZE_MAX)
+				<< ", pointsPerDgram=" << pointsPerDgram
+				<< ", nSucceeded=" << nSucceeded
+				<< ", totalPoints=" << totalPoints
+				<< ", highIntensityCount=" << highIntensityCount << std::endl;
+	#endif
+
+			callOriginalCallback(success);
+		});
+
+		if (!shouldContinue)
 		{
+			/* We intentionally don't call collateKernelComplete() here for the
+			 * same reason as above.
+			 */
 			callOriginalCallback(false);
 			return;
 		}
-
-		uint32_t nSucceeded = context->frameAssemblyResult.nSucceeded.load();
-
-		int returnMode = static_cast<int>(engine.parent.device->currentReturnMode);
-		size_t pointsPerDgram = livoxProto1::Device::getNPointsPerDgram(
-			returnMode);
-		size_t totalPoints = nSucceeded * pointsPerDgram;
-
-		// Count points with intensity greater than 116
-		size_t highIntensityCount = 0;
-		if (context->intensityStimFrame.has_value())
-		{
-			StimulusFrame& intensityFrame = context->intensityStimFrame->get();
-			float* intensityFloats = reinterpret_cast<float*>(intensityFrame.slotDesc.vaddr);
-			for (size_t i = 0; i < totalPoints; ++i)
-			{
-				float intensity = intensityFloats[i];
-				if (intensity >= 116.0f)
-				{
-					++highIntensityCount;
-				}
-			}
-		}
-		(void)highIntensityCount;
-
-#if 0
-		std::cout << __func__ << ": intensityRingBufferIndex="
-			<< (context->intensityStimFrame.has_value() ?
-				context->intensityStimFrame->get().ringBufferIndex : SIZE_MAX)
-			<< ", pointsPerDgram=" << pointsPerDgram
-			<< ", nSucceeded=" << nSucceeded
-			<< ", totalPoints=" << totalPoints
-			<< ", highIntensityCount=" << highIntensityCount << std::endl;
-#endif
-
-		callOriginalCallback(success);
 	}
 };
 
@@ -1256,8 +1271,7 @@ void OpenClCollatingAndMeshingEngine::compactCollateAndMeshFrameReq(
 	sscl::cps::Callback<compactCollateAndMeshFrameReqCbFn> callback)
 {
 	{
-		sscl::SpinLock::Guard lock(shouldAcceptRequestsLock);
+		if (openClCollMeshEngnCanceler.isCancellationRequested())
-		if (!shouldAcceptRequests)
 		{
 			callback.callbackFn(false, stimulusFrame);
 			return;

stimBuffApis/livoxGen1/openClCollatingAndMeshingEngine.h

@@ -15,7 +15,7 @@
 #include <CL/cl.h>
 #include <spinscale/asynchronousLoop.h>
 #include <spinscale/cps/callback.h>
-#include <spinscale/spinLock.h>
+#include <spinscale/syncCancelerForAsyncWork.h>
 #include <user/stimulusFrame.h>
 #include <user/stagingBuffer.h>
 #include <user/frameAssemblyDesc.h>
@@ -150,8 +150,7 @@ private:
 	cl_mem clAverageIntensityBuffer;
 
 	// State tracking
-	sscl::SpinLock shouldAcceptRequestsLock;
+	sscl::SyncCancelerForAsyncWork openClCollMeshEngnCanceler;
-	bool shouldAcceptRequests;
 	bool compactIsRunning;
 	bool collateIsRunning;
 	cl_event currentCompactKernelEvent;

stimBuffApis/livoxGen1/pcloudStimulusProducer.cpp

@@ -464,117 +464,137 @@ public:
 	void produceFrameReq1_doAssemble_posted(
 		std::shared_ptr<ProduceFrameReq> context)
 	{
-		sscl::SpinLock::Guard lock(pcloudProducer.shouldContinueLock);
+		const bool shouldContinue = pcloudProducer.stimulusProducerCanceler
-		if (!pcloudProducer.shouldContinue)
+			.execUncancelableSegmentOrAbort(
+				[this, context]()
+			{
+				pcloudProducer.ioUringAssemblyEngine.assembleFrameReq(
+					{context, std::bind(
+						&ProduceFrameReq::produceFrameReq2_assembleDone,
+						context.get(), context,
+						std::placeholders::_1, std::placeholders::_2)});
+			});
+
+		if (!shouldContinue)
 		{
 			callOriginalCallback();
 			return;
 		}
-
-		pcloudProducer.ioUringAssemblyEngine.assembleFrameReq(
-			{context, std::bind(
-				&ProduceFrameReq::produceFrameReq2_assembleDone,
-				context.get(), context,
-				std::placeholders::_1, std::placeholders::_2)});
 	}
 
 	void produceFrameReq2_assembleDone(
 		std::shared_ptr<ProduceFrameReq> context,
 		bool success, sscl::AsynchronousLoop loop)
 	{
-		sscl::SpinLock::Guard lock(pcloudProducer.shouldContinueLock);
+		bool shouldContinue = pcloudProducer.stimulusProducerCanceler
-		if (!pcloudProducer.shouldContinue)
+			.execUncancelableSegmentOrAbort(
+				[this, context, success, loop]()
 		{
-			callOriginalCallback();
+			if (!success)
-			return;
+			{
-		}
+				callOriginalCallback();
 
-		if (!success)
+				if (pcloudProducer.attachedStimulusBuffers.size() > 0) {
-		{
+					std::cerr << __func__
-			callOriginalCallback();
+						<< ": Failed to assemble frame.\n";
-
+				}
-			if (pcloudProducer.attachedStimulusBuffers.size() > 0) {
+				return;
-				std::cerr << __func__ << ": Failed to assemble frame.\n";
 			}
+
+			context->frameAssemblyResult = loop;
+
+			// Check if intensity buffer is attached and acquire frame if so
+			if (auto intensityBuff = pcloudProducer
+				.intensityStimulusBuffer.load(
+					std::memory_order_acquire))
+			{
+				size_t intensityRingbuffIndex = intensityBuff
+					->ringBuffer.getIndexToProduceInto();
+
+				StimulusFrame& intensityStimFrame = intensityBuff
+					->ringBuffer.getDataAtSlot(
+						intensityRingbuffIndex);
+
+				intensityStimFrame.lock.writeAcquire();
+				context->intensityStimFrame = std::make_optional(
+					std::ref(intensityStimFrame));
+			}
+			else {
+				context->intensityStimFrame = std::nullopt;
+			}
+
+			// Check if light ambience buffer is attached and acquire frame if so
+			std::optional<AmbienceProductionDesc>
+				lightAmbienceProductionDescDesc;
+			if (auto lightAmbienceBuff =
+				pcloudProducer.lightAmbienceStimulusBuffer.load(
+					std::memory_order_acquire))
+			{
+				size_t lightAmbienceRingbuffIndex = lightAmbienceBuff
+					->ringBuffer.getIndexToProduceInto();
+
+				StimulusFrame& lightAmbienceStimFrame =
+					lightAmbienceBuff->ringBuffer.getDataAtSlot(
+						lightAmbienceRingbuffIndex);
+
+				lightAmbienceStimFrame.lock.writeAcquire();
+				context->lightAmbienceStimFrame = std::make_optional(
+					std::ref(lightAmbienceStimFrame));
+				lightAmbienceProductionDescDesc =
+					AmbienceProductionDesc{
+						std::ref(lightAmbienceStimFrame),
+						lightAmbienceBuff
+							->passbandCountGtComparator};
+			}
+			else {
+				context->lightAmbienceStimFrame = std::nullopt;
+			}
+
+			// Check if dark ambience buffer is attached and acquire frame if so
+			std::optional<AmbienceProductionDesc>
+				darkAmbienceProductionDescDesc;
+			if (auto darkAmbienceBuff =
+				pcloudProducer.darkAmbienceStimulusBuffer.load(
+					std::memory_order_acquire))
+			{
+				size_t darkAmbienceRingbuffIndex = darkAmbienceBuff
+					->ringBuffer.getIndexToProduceInto();
+
+				StimulusFrame& darkAmbienceStimFrame =
+					darkAmbienceBuff->ringBuffer.getDataAtSlot(
+						darkAmbienceRingbuffIndex);
+
+				darkAmbienceStimFrame.lock.writeAcquire();
+				context->darkAmbienceStimFrame = std::make_optional(
+					std::ref(darkAmbienceStimFrame));
+				darkAmbienceProductionDescDesc =
+					AmbienceProductionDesc{
+						std::ref(darkAmbienceStimFrame),
+						darkAmbienceBuff
+							->passbandCountLtComparator};
+			}
+			else {
+				context->darkAmbienceStimFrame = std::nullopt;
+			}
+
+			pcloudProducer.openClCollatingAndMeshingEngine
+				.compactCollateAndMeshFrameReq(
+					context->frameAssemblyResult, stimulusFrame,
+					context->intensityStimFrame,
+					std::move(lightAmbienceProductionDescDesc),
+					std::move(darkAmbienceProductionDescDesc),
+					{context, std::bind(
+						&ProduceFrameReq
+							::produceFrameReq3_compactCollateDone,
+						context.get(), context,
+						std::placeholders::_1, std::placeholders::_2)});
+		});
+
+		if (!shouldContinue)
+		{
+			callOriginalCallback();
 			return;
 		}
-
-		context->frameAssemblyResult = loop;
-
-		// Check if intensity buffer is attached and acquire frame if so
-		if (auto intensityBuff = pcloudProducer.intensityStimulusBuffer.load(
-			std::memory_order_acquire))
-		{
-			size_t intensityRingbuffIndex = intensityBuff
-				->ringBuffer.getIndexToProduceInto();
-
-			StimulusFrame& intensityStimFrame = intensityBuff
-				->ringBuffer.getDataAtSlot(
-					intensityRingbuffIndex);
-
-			intensityStimFrame.lock.writeAcquire();
-			context->intensityStimFrame = std::make_optional(
-				std::ref(intensityStimFrame));
-		}
-		else {
-			context->intensityStimFrame = std::nullopt;
-		}
-
-		// Check if light ambience buffer is attached and acquire frame if so
-		std::optional<AmbienceProductionDesc> lightAmbienceProductionDescDesc;
-		if (auto lightAmbienceBuff =
-			pcloudProducer.lightAmbienceStimulusBuffer.load(
-				std::memory_order_acquire))
-		{
-			size_t lightAmbienceRingbuffIndex = lightAmbienceBuff
-				->ringBuffer.getIndexToProduceInto();
-
-			StimulusFrame& lightAmbienceStimFrame = lightAmbienceBuff
-				->ringBuffer.getDataAtSlot(lightAmbienceRingbuffIndex);
-
-			lightAmbienceStimFrame.lock.writeAcquire();
-			context->lightAmbienceStimFrame = std::make_optional(
-				std::ref(lightAmbienceStimFrame));
-			lightAmbienceProductionDescDesc = AmbienceProductionDesc{
-				std::ref(lightAmbienceStimFrame),
-				lightAmbienceBuff->passbandCountGtComparator};
-		}
-		else {
-			context->lightAmbienceStimFrame = std::nullopt;
-		}
-
-		// Check if dark ambience buffer is attached and acquire frame if so
-		std::optional<AmbienceProductionDesc> darkAmbienceProductionDescDesc;
-		if (auto darkAmbienceBuff =
-			pcloudProducer.darkAmbienceStimulusBuffer.load(
-				std::memory_order_acquire))
-		{
-			size_t darkAmbienceRingbuffIndex = darkAmbienceBuff
-				->ringBuffer.getIndexToProduceInto();
-
-			StimulusFrame& darkAmbienceStimFrame = darkAmbienceBuff
-				->ringBuffer.getDataAtSlot(darkAmbienceRingbuffIndex);
-
-			darkAmbienceStimFrame.lock.writeAcquire();
-			context->darkAmbienceStimFrame = std::make_optional(
-				std::ref(darkAmbienceStimFrame));
-			darkAmbienceProductionDescDesc = AmbienceProductionDesc{
-				std::ref(darkAmbienceStimFrame),
-				darkAmbienceBuff->passbandCountLtComparator};
-		}
-		else {
-			context->darkAmbienceStimFrame = std::nullopt;
-		}
-
-		pcloudProducer.openClCollatingAndMeshingEngine.compactCollateAndMeshFrameReq(
-			loop, stimulusFrame,
-			context->intensityStimFrame,
-			std::move(lightAmbienceProductionDescDesc),
-			std::move(darkAmbienceProductionDescDesc),
-			{context, std::bind(
-				&ProduceFrameReq::produceFrameReq3_compactCollateDone,
-				context.get(), context,
-				std::placeholders::_1, std::placeholders::_2)});
 	}
 
 	void produceFrameReq3_compactCollateDone(
@@ -603,7 +623,10 @@ public:
 		}
 #endif
 
-		// Release intensity frame if it was used
+		/**	EXPLANATION:
+		 * Release intensity/ambience frames if they were supplied/used,
+		 * regardless of whether or not a cancelation request occurred.
+		 */
 		if (context->intensityStimFrame.has_value()) {
 			context->intensityStimFrame->get().lock.writeRelease();
 		}
@@ -615,130 +638,169 @@ public:
 			context->darkAmbienceStimFrame->get().lock.writeRelease();
 		}
 
-		sscl::SpinLock::Guard lock(pcloudProducer.shouldContinueLock);
+		if (!success)
-		if (!pcloudProducer.shouldContinue)
+		{
+			callOriginalCallback();
+
+			std::cerr << __func__
+				<< ": Failed to compact and collate frame"
+				<< std::endl;
+
+			return;
+		}
+
+		/**	EXPLANATION:
+		 * Cancellation early exit for the success path. Analogous to the
+		 * (legacy, removed) pre-canceler check under shouldContinueLock before
+		 * lock.unlockPrematurely() in the former CPS version of this handler.
+		 *
+		 * Assumptions that make the unlocked tail (dump, debug logging, stage
+		 * durations, final callOriginalCallback()) safe without holding
+		 * stimulusProducerCanceler.s.lock:
+		 *
+		 * 1. This handler is only entered from
+		 *    CompactCollateAndMeshFrameReq4's execUncancelableSegmentOrAbort
+		 *    body, so openClCollatingAndMeshingEngine::finalize() cannot
+		 *    tear down OpenCL/engine state until this function returns.
+		 *
+		 * 2. PcloudStimulusProducer::stop() finalizes OpenCL before io_uring,
+		 *    so getCompactKernelDuration()/getCollateKernelDuration() and
+		 *    getAssemblyDuration() are not racing engine finalize here.
+		 *
+		 * 3. dump/logging reads only producer-owned state (pcloudFrameDumper,
+		 *    collationBuffer, device, context->frameAssemblyResult) that
+		 *    stop()/finalize() do not destroy.
+		 *
+		 * 4. A stop() that lands after this read but before the tail is
+		 *    intentional stale work (same as unlockPrematurely()), not UAF.
+		 *
+		 * Rework to run portions inside stimulusProducerCanceler
+		 * execUncancelableSegmentOrAbort if any of the above ceases to hold:
+		 * e.g. this callback is invoked outside the OpenCL uncancelable
+		 * segment, the tail begins touching engine or buffer state that
+		 * finalize() resets, or stop() ordering changes so teardown can
+		 * interleave with the unlocked tail.
+		 */
+		const bool shouldContinue =
+			!pcloudProducer.stimulusProducerCanceler.isCancellationRequested();
+
+		if (!shouldContinue)
 		{
 			callOriginalCallback();
 			return;
 		}
 
-		if (!success) {
+		if (pcloudProducer.pcloudFrameDumper.isEnabled())
-			std::cerr << __func__ << ": Failed to compact and collate frame" << std::endl;
-		} else
 		{
-			lock.unlockPrematurely();
+			try
-			if (pcloudProducer.pcloudFrameDumper.isEnabled())
 			{
-				try
+				pcloudProducer.pcloudFrameDumper.dumpProducedFrame(
-				{
+					*pcloudProducer.device,
-					pcloudProducer.pcloudFrameDumper.dumpProducedFrame(
+					pcloudProducer.collationBuffer,
-						*pcloudProducer.device,
+					context->frameAssemblyResult);
-						pcloudProducer.collationBuffer,
-						context->frameAssemblyResult);
-				}
-				catch (const std::exception& e)
-				{
-					std::cerr << __func__ << ": Failed to dump pcloud frame: "
-						<< e.what() << std::endl;
-				}
 			}
+			catch (const std::exception& e)
+			{
+				std::cerr << __func__ << ": Failed to dump pcloud frame: "
+					<< e.what() << std::endl;
+			}
+		}
 
 #if SMO_DEBUG_PCLOUD_AMBIENCE_INTRIN
-			if (logLightAmbience)
+		if (logLightAmbience)
+		{
+			auto lightBuff =
+				pcloudProducer.lightAmbienceStimulusBuffer.load(
+					std::memory_order_acquire);
+			if (lightBuff)
 			{
-				auto lightBuff =
+				std::cerr << __func__ << ": pcloudLightAmbience "
-					pcloudProducer.lightAmbienceStimulusBuffer.load(
+					<< "passbandCount=" << logLightPassbandCount
-						std::memory_order_acquire);
+					<< " (per-slot avg intensity "
-				if (lightBuff)
+					<< ambienceComparatorOpChar(
+						lightBuff->passbandCountGtComparator.op)
+					<< " " << lightBuff->passbandCountGtComparator.value
+					<< ")";
+				if (lightBuff->negtrinInterestConfig.has_value())
 				{
-					std::cerr << __func__ << ": pcloudLightAmbience "
+					const auto& nc = *lightBuff->negtrinInterestConfig;
-						<< "passbandCount=" << logLightPassbandCount
+					std::cerr << " negtrinInterestThr=" << nc.threshold;
-						<< " (per-slot avg intensity "
+					if (nc.percentage != 0U)
-						<< ambienceComparatorOpChar(
-							lightBuff->passbandCountGtComparator.op)
-						<< " " << lightBuff->passbandCountGtComparator.value
-						<< ")";
-					if (lightBuff->negtrinInterestConfig.has_value())
 					{
-						const auto& nc = *lightBuff->negtrinInterestConfig;
+						std::cerr << " (from " << nc.percentage << "%)";
-						std::cerr << " negtrinInterestThr=" << nc.threshold;
-						if (nc.percentage != 0U)
-						{
-							std::cerr << " (from " << nc.percentage << "%)";
-						}
-						std::cerr << " meetsNegtrinInterest="
-							<< (lightBuff->shouldTriggerNegtrinEvent(
-								logLightPassbandCount)
-								? "yes" : "no");
 					}
-					else
+					std::cerr << " meetsNegtrinInterest="
-					{
+						<< (lightBuff->shouldTriggerNegtrinEvent(
-						std::cerr << " negtrinInterest(n/a)";
+							logLightPassbandCount)
-					}
+							? "yes" : "no");
-					std::cerr << std::endl;
 				}
+				else
+				{
+					std::cerr << " negtrinInterest(n/a)";
+				}
+				std::cerr << std::endl;
 			}
-			if (logDarkAmbience)
+		}
+		if (logDarkAmbience)
+		{
+			auto darkBuff =
+				pcloudProducer.darkAmbienceStimulusBuffer.load(
+					std::memory_order_acquire);
+			if (darkBuff)
 			{
-				auto darkBuff =
+				std::cerr << __func__ << ": pcloudDarkAmbience "
-					pcloudProducer.darkAmbienceStimulusBuffer.load(
+					<< "passbandCount=" << logDarkPassbandCount
-						std::memory_order_acquire);
+					<< " (per-slot avg intensity "
-				if (darkBuff)
+					<< ambienceComparatorOpChar(
+						darkBuff->passbandCountLtComparator.op)
+					<< " " << darkBuff->passbandCountLtComparator.value
+					<< ")";
+				if (darkBuff->postrinInterestConfig.has_value())
 				{
-					std::cerr << __func__ << ": pcloudDarkAmbience "
+					const auto& pc = *darkBuff->postrinInterestConfig;
-						<< "passbandCount=" << logDarkPassbandCount
+					std::cerr << " postrinInterestThr=" << pc.threshold;
-						<< " (per-slot avg intensity "
+					if (pc.percentage != 0U)
-						<< ambienceComparatorOpChar(
-							darkBuff->passbandCountLtComparator.op)
-						<< " " << darkBuff->passbandCountLtComparator.value
-						<< ")";
-					if (darkBuff->postrinInterestConfig.has_value())
 					{
-						const auto& pc = *darkBuff->postrinInterestConfig;
+						std::cerr << " (from " << pc.percentage << "%)";
-						std::cerr << " postrinInterestThr=" << pc.threshold;
-						if (pc.percentage != 0U)
-						{
-							std::cerr << " (from " << pc.percentage << "%)";
-						}
-						std::cerr << " meetsPostrinInterest="
-							<< (darkBuff->shouldTriggerPostrinEvent(
-								logDarkPassbandCount)
-								? "yes" : "no");
 					}
-					else
+					std::cerr << " meetsPostrinInterest="
-					{
+						<< (darkBuff->shouldTriggerPostrinEvent(
-						std::cerr << " postrinInterest(n/a)";
+							logDarkPassbandCount)
-					}
+							? "yes" : "no");
-					std::cerr << std::endl;
 				}
+				else
+				{
+					std::cerr << " postrinInterest(n/a)";
+				}
+				std::cerr << std::endl;
 			}
+		}
 #endif
 
 #if SMO_PRINT_PCLOUD_STAGE_DURATIONS
-			const auto logNow = std::chrono::system_clock::now();
+		const auto logNow = std::chrono::system_clock::now();
-			const std::time_t logTime =
+		const std::time_t logTime =
-				std::chrono::system_clock::to_time_t(logNow);
+			std::chrono::system_clock::to_time_t(logNow);
-			const auto logSubsecMs =
+		const auto logSubsecMs =
-				std::chrono::duration_cast<std::chrono::milliseconds>(
+			std::chrono::duration_cast<std::chrono::milliseconds>(
-					logNow.time_since_epoch()) % 1000;
+				logNow.time_since_epoch()) % 1000;
-			auto assemblyDuration =
+		auto assemblyDuration =
-				pcloudProducer.ioUringAssemblyEngine.getAssemblyDuration();
+			pcloudProducer.ioUringAssemblyEngine.getAssemblyDuration();
-			auto compactDuration =
+		auto compactDuration =
-				pcloudProducer.openClCollatingAndMeshingEngine
+			pcloudProducer.openClCollatingAndMeshingEngine
-					.getCompactKernelDuration();
+				.getCompactKernelDuration();
-			auto collateDuration =
+		auto collateDuration =
-				pcloudProducer.openClCollatingAndMeshingEngine
+			pcloudProducer.openClCollatingAndMeshingEngine
-					.getCollateKernelDuration();
+				.getCollateKernelDuration();
-			std::cout << std::put_time(std::localtime(&logTime), "%T")
+		std::cout << std::put_time(std::localtime(&logTime), "%T")
-				<< '.' << std::setfill('0') << std::setw(3)
+			<< '.' << std::setfill('0') << std::setw(3)
-				<< logSubsecMs.count() << ' '
+			<< logSubsecMs.count() << ' '
-				<< __func__ << ": stage durations: assembly="
+			<< __func__ << ": stage durations: assembly="
-				<< assemblyDuration.count()
+			<< assemblyDuration.count()
-				<< "ms, compactKernel=" << compactDuration.count()
+			<< "ms, compactKernel=" << compactDuration.count()
-				<< "ms, collateKernel=" << collateDuration.count()
+			<< "ms, collateKernel=" << collateDuration.count()
-				<< "ms" << std::endl;
+			<< "ms" << std::endl;
 #endif
-		}
 
 		callOriginalCallback();
 	}
@@ -748,10 +810,9 @@ void PcloudStimulusProducer::produceFrameReq(
 	sscl::cps::Callback<produceFrameReqCbFn> callback)
 {
 	/**	EXPLANATION:
-	 * We shouldn't acquire the StimulusProducer::shouldContinueLock here because
+	 * We don't do any additional canceler-lock acquisition here because
-	 * this function is called from
+	 * callback segment methods already use stimulusProducerCanceler
-	 * StimulusProducer::stimFrameProductionTimesliceInd(), which is already
+	 * checkpoints before running uncancelable work.
-	 * holding the lock.
 	 */
 	auto caller = smoHooksPtr->ComponentThread_getSelf();
 	auto request = std::make_shared<ProduceFrameReq>(