StagingBuff: support both Mlock & IOUring pin; Use in IoUAssmEngn

We use io_uring_register_buffers() for IoUringAssemblyEngine instead
of using mlock(). This __appears__ to have reduced CPU utilization on
the Dell laptop. Could also be that we recently upgraded total RAM
from 8GiB to 32GiB.

stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp

@@ -27,8 +27,6 @@
 #include "pcloudStimulusProducer.h"
 #include "livoxGen1.h"
 
-// #define REGISTER_IOURING_BUFFERS
-
 namespace smo {
 namespace stim_buff {
 
@@ -116,10 +114,6 @@ bool IoUringAssemblyEngine::setup()
 		assembledSlotsTracker[i].ioVec.iov_len = slot.nBytes;
 	}
 
-	// Declare iovec early to avoid goto crossing initialization
-#ifdef REGISTER_IOURING_BUFFERS
-	struct iovec iov;
-#endif
 	int ret;
 
 	/**	EXPLANATION:
@@ -134,23 +128,27 @@ bool IoUringAssemblyEngine::setup()
 	if (ret < 0)
 		{ goto cleanup; }
 
-#ifdef REGISTER_IOURING_BUFFERS
-	// Register staging buffer with io_uring for DMA-apt I/O
-	iov = parent.assemblyBuffer.getIoUringRegisterIoVec();
-	ret = io_uring_register_buffers(&ring, &iov, 1);
-	if (ret < 0)
-		{ goto cleanup_ring; }
-#endif
+	try
+	{
+		if (assemblyBufferIoUringPinner)
+		{
+			throw std::runtime_error(std::string(__func__)
+				+ ": assemblyBufferIoUringPinner already exists");
+		}
+
+		assemblyBufferIoUringPinner =
+			parent.assemblyBuffer.makeIoUringPinner(&ring);
+	}
+	catch (const std::exception&)
+	{
+		goto cleanup_ring;
+	}
 
 	// Create eventfd for CQE notifications (used with boost's unified loop)
 	eventfdFd = eventfd(0, EFD_NONBLOCK);
 	if (eventfdFd < 0)
 	{
-#ifdef REGISTER_IOURING_BUFFERS
-		goto cleanup_buffers;
-#else
 		goto cleanup_ring;
-#endif
 	}
 
 	// Register eventfd with io_uring
@@ -164,11 +162,8 @@ bool IoUringAssemblyEngine::setup()
 cleanup_eventfd:
 	close(eventfdFd);
 	eventfdFd = -1;
-#ifdef REGISTER_IOURING_BUFFERS
-cleanup_buffers:
-	io_uring_unregister_buffers(&ring);
-#endif
 cleanup_ring:
+	assemblyBufferIoUringPinner.reset();
 	io_uring_queue_exit(&ring);
 cleanup:
 	return false;
@@ -217,9 +212,7 @@ void IoUringAssemblyEngine::finalize()
 
 	if (wasAcceptingRequests)
 	{
-#ifdef REGISTER_IOURING_BUFFERS
-		io_uring_unregister_buffers(&ring);
-#endif
+		assemblyBufferIoUringPinner.reset();
 		io_uring_queue_exit(&ring);
 	}
 

stimBuffApis/livoxGen1/ioUringAssemblyEngine.h

@@ -21,6 +21,7 @@
 #include <spinscale/callback.h>
 #include <spinscale/spinLock.h>
 #include <user/frameAssemblyDesc.h>
+#include <user/stagingBuffer.h>
 
 #define IOURINGASSM_ENGN_FRAME_ASSEM_TIMEOUT_MS		\
 	(CONFIG_STIMBUFF_FRAME_PERIOD_MS / 2)
@@ -73,6 +74,7 @@ private:
 	uint64_t eventfd_value;  // Buffer for async_read_some
 	// Point cloud data socket descriptor
 	std::shared_ptr<boost::asio::posix::stream_descriptor> pcloudDataFdDesc;
+	std::unique_ptr<StagingBuffer::IoUringPinner> assemblyBufferIoUringPinner;
 
 	// Stall detection timer
 	boost::asio::deadline_timer stallTimer;
@@ -122,4 +124,3 @@ public:
 
 #endif // _LIVOX_GEN1_IOURING_ASSEMBLY_ENGINE_H
 
-

stimBuffApis/livoxGen1/meshStimulusBuffer.h

@@ -34,15 +34,14 @@ public:
 
 	~MeshStimulusBuffer() = default;
 
-	// Non-copyable, movable
+	// Non-copyable, non-movable: inherited pinner lifetime is instance-bound
 	MeshStimulusBuffer(const MeshStimulusBuffer&) = delete;
 	MeshStimulusBuffer& operator=(const MeshStimulusBuffer&) = delete;
-	MeshStimulusBuffer(MeshStimulusBuffer&&) = default;
-	MeshStimulusBuffer& operator=(MeshStimulusBuffer&&) = default;
+	MeshStimulusBuffer(MeshStimulusBuffer&&) = delete;
+	MeshStimulusBuffer& operator=(MeshStimulusBuffer&&) = delete;
 };
 
 } // namespace stim_buff
 } // namespace smo
 
 #endif // _LIVOX_GEN1_MESH_STIMULUS_BUFFER_H
-

stimBuffApis/livoxGen1/pcloudAmbienceStimulusBuffer.h

@@ -73,11 +73,11 @@ public:
 
 	~PcloudAmbienceStimulusBuffer() = default;
 
-	// Non-copyable, movable
+	// Non-copyable, non-movable: inherited pinner lifetime is instance-bound
 	PcloudAmbienceStimulusBuffer(const PcloudAmbienceStimulusBuffer&) = delete;
 	PcloudAmbienceStimulusBuffer& operator=(const PcloudAmbienceStimulusBuffer&) = delete;
-	PcloudAmbienceStimulusBuffer(PcloudAmbienceStimulusBuffer&&) = default;
-	PcloudAmbienceStimulusBuffer& operator=(PcloudAmbienceStimulusBuffer&&) = default;
+	PcloudAmbienceStimulusBuffer(PcloudAmbienceStimulusBuffer&&) = delete;
+	PcloudAmbienceStimulusBuffer& operator=(PcloudAmbienceStimulusBuffer&&) = delete;
 
 public:
 	uint32_t postrinInterestPercentage;

stimBuffApis/livoxGen1/pcloudIntensityStimulusBuffer.h

@@ -35,15 +35,15 @@ public:
 
 	~PcloudIntensityStimulusBuffer() = default;
 
-	// Non-copyable, movable
+	// Non-copyable, non-movable: inherited pinner lifetime is instance-bound
 	PcloudIntensityStimulusBuffer(
 		const PcloudIntensityStimulusBuffer&) = delete;
 	PcloudIntensityStimulusBuffer& operator=(
 		const PcloudIntensityStimulusBuffer&) = delete;
 	PcloudIntensityStimulusBuffer(
-		PcloudIntensityStimulusBuffer&&) = default;
+		PcloudIntensityStimulusBuffer&&) = delete;
 	PcloudIntensityStimulusBuffer& operator=(
-		PcloudIntensityStimulusBuffer&&) = default;
+		PcloudIntensityStimulusBuffer&&) = delete;
 };
 
 } // namespace stim_buff

stimBuffApis/livoxGen1/pcloudStimulusProducer.cpp

@@ -95,10 +95,13 @@ collationBuffer(
 	StagingBuffer::IOEngineConstraints::openClInputConstraints,
 	StagingBuffer::IOEngineConstraints::openClInputConstraints,
 	nDgramsPerStagingBufferFrame),
+collationBufferMlockPinner(collationBuffer.makeMlockPinner()),
 averageIntensityBuffer(
 	openClAverageIntensityConstraints,
 	openClAverageIntensityConstraints,
 	nDgramsPerStagingBufferFrame),
+averageIntensityBufferMlockPinner(
+	averageIntensityBuffer.makeMlockPinner()),
 tempStimulusFrameMem(0),
 tempStimulusFrame(
 	FrameAssemblyDesc::SlotDesc{

stimBuffApis/livoxGen1/pcloudStimulusProducer.h

@@ -52,11 +52,11 @@ public:
 
 	~PcloudStimulusProducer() = default;
 
-	// Non-copyable, movable
+	// Non-copyable, non-movable: pinners hold buffer instance references
 	PcloudStimulusProducer(const PcloudStimulusProducer&) = delete;
 	PcloudStimulusProducer& operator=(const PcloudStimulusProducer&) = delete;
-	PcloudStimulusProducer(PcloudStimulusProducer&&) = default;
-	PcloudStimulusProducer& operator=(PcloudStimulusProducer&&) = default;
+	PcloudStimulusProducer(PcloudStimulusProducer&&) = delete;
+	PcloudStimulusProducer& operator=(PcloudStimulusProducer&&) = delete;
 
 	// Control methods
 	void start() override;
@@ -94,7 +94,10 @@ public:
 	StagingBuffer assemblyBuffer;
 	IoUringAssemblyEngine ioUringAssemblyEngine;
 	StagingBuffer collationBuffer;
+	std::unique_ptr<StagingBuffer::MlockPinner> collationBufferMlockPinner;
 	StagingBuffer averageIntensityBuffer;
+	std::unique_ptr<StagingBuffer::MlockPinner>
+		averageIntensityBufferMlockPinner;
 	size_t tempStimulusFrameMem;
 	StimulusFrame tempStimulusFrame;
 	std::atomic<std::shared_ptr<MeshStimulusBuffer>> meshStimulusBuffer;