Move StagingBuffer+FrameAssemblyDesc into libattachmentSupport

This is in preparation for using StagingBuffer to implement
StimulusFrame and StimulusBuffer.
This commit is contained in:
2025-11-15 20:47:40 -04:00
parent 2d1c026cc2
commit d277c29394
10 changed files with 13 additions and 11 deletions
-1
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@@ -58,7 +58,6 @@ if(ENABLE_STIMBUFFAPI_livoxGen1)
add_library(livoxGen1 SHARED
livoxGen1.cpp
stagingBuffer.cpp
pcloudStimulusProducer.cpp
ioUringAssemblyEngine.cpp
openClCollatingAndMeshingEngine.cpp
@@ -1,65 +0,0 @@
#ifndef _LIVOX_GEN1_FRAME_ASSEMBLY_DESC_H
#define _LIVOX_GEN1_FRAME_ASSEMBLY_DESC_H
#include <cstddef>
#include <cstdint>
#include <vector>
#include <string>
#include <sstream>
namespace smo {
namespace stim_buff {
class FrameAssemblyDesc
{
public:
struct SlotDesc
{
size_t offsetBytes; // offset from frame base
uint8_t* vaddr; // direct pointer into StagingBuffer memory
size_t nBytes; // slot capacity in bytes
};
public:
FrameAssemblyDesc() = default;
FrameAssemblyDesc(
size_t n, size_t slotSize,
size_t frameStride,
std::vector<SlotDesc> slotList)
: numSlots(n), slotSizeBytes(slotSize),
frameStrideBytes(frameStride),
slots(std::move(slotList)) {}
inline std::string stringify() const {
std::ostringstream oss;
oss << "FrameAssemblyDesc{"
<< "numSlots=" << numSlots
<< ", slotSizeBytes=" << slotSizeBytes
<< ", frameStrideBytes=" << frameStrideBytes
<< ", slots=[";
const size_t preview = slots.size() < 4 ? slots.size() : 4;
for (size_t i = 0; i < preview; ++i) {
oss << "{off=" << slots[i].offsetBytes
<< ", nBytes=" << slots[i].nBytes
<< ", vaddr=" << (const void*)slots[i].vaddr << "}";
if (i + 1 < preview) oss << ",";
}
if (slots.size() > preview) oss << ", ...";
oss << "]}";
return oss.str();
}
public:
size_t numSlots;
size_t slotSizeBytes;
size_t frameStrideBytes;
std::vector<SlotDesc> slots;
};
} // namespace stim_buff
} // namespace smo
#endif // _LIVOX_GEN1_FRAME_ASSEMBLY_DESC_H
@@ -19,7 +19,7 @@
#include <asynchronousLoop.h>
#include <callback.h>
#include <spinLock.h>
#include "frameAssemblyDesc.h"
#include <user/frameAssemblyDesc.h>
namespace smo {
namespace stim_buff {
@@ -15,7 +15,7 @@
#include "openClCollatingAndMeshingEngine.h"
#include "pcloudStimulusProducer.h"
#include "openClKernels.h"
#include "frameAssemblyDesc.h"
#include <user/frameAssemblyDesc.h>
#include "ioUringAssemblyEngine.h"
namespace smo {
@@ -15,8 +15,8 @@
#include <callback.h>
#include <spinLock.h>
#include <user/stimulusFrame.h>
#include "stagingBuffer.h"
#include "frameAssemblyDesc.h"
#include <user/stagingBuffer.h>
#include <user/frameAssemblyDesc.h>
namespace smo {
namespace stim_buff {
@@ -8,7 +8,7 @@
#include <asynchronousLoop.h>
#include <user/stimulusFrame.h>
#include "pcloudStimulusProducer.h"
#include "frameAssemblyDesc.h"
#include <user/frameAssemblyDesc.h>
namespace smo {
namespace stim_buff {
@@ -8,7 +8,7 @@
#include <livoxProto1/device.h>
#include <asynchronousContinuation.h>
#include <callback.h>
#include "stagingBuffer.h"
#include <user/stagingBuffer.h>
#include "ioUringAssemblyEngine.h"
#include "openClCollatingAndMeshingEngine.h"
#include "pcloudXyzStimulusBuffer.h"
-231
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@@ -1,231 +0,0 @@
#include "stagingBuffer.h"
#include <unistd.h>
#include <cstdint>
#include <stdexcept>
#include <sys/mman.h>
#include <vector>
namespace smo {
namespace stim_buff {
// Static defaults for io_uring
const StagingBuffer::IOEngineConstraints
StagingBuffer::IOEngineConstraints::ioUringConstraints(
// slotStartAlignmentByteVal (page alignment for DMA)
static_cast<size_t>(sysconf(_SC_PAGE_SIZE)),
// slotPadToNBytes (MTU 1500 - UDP/IP header 28)
1472,
// frameStartAlignmentByteVal (page alignment for DMA)
static_cast<size_t>(sysconf(_SC_PAGE_SIZE)),
// framePadToNBytes (MTU 1500 - UDP/IP header 28)
static_cast<size_t>(sysconf(_SC_PAGE_SIZE))
);
// Static defaults for OpenCL input
const StagingBuffer::IOEngineConstraints
StagingBuffer::IOEngineConstraints::openClInputConstraints(
// slotStartAlignmentByteVal (page alignment)
static_cast<size_t>(sysconf(_SC_PAGE_SIZE)),
// slotPadToNBytes (XYZI point size)
16,
// frameStartAlignmentByteVal (page alignment)
static_cast<size_t>(sysconf(_SC_PAGE_SIZE)),
// framePadToNBytes (pointer size)
static_cast<size_t>(sysconf(_SC_PAGE_SIZE))
);
// Helper function to calculate maximum alignment needed for first slot
// (must satisfy both frame and slot alignment)
static size_t calculateMaxAlignment(
size_t frameStartAlignmentByteVal,
size_t slotStartAlignmentByteVal)
{
if (frameStartAlignmentByteVal >= slotStartAlignmentByteVal)
{
if (frameStartAlignmentByteVal % slotStartAlignmentByteVal == 0)
{ return frameStartAlignmentByteVal; }
else
{
// Need LCM, but for simplicity use the larger alignment
// In practice, alignments are usually powers of 2, so this should work
return std::max(
frameStartAlignmentByteVal, slotStartAlignmentByteVal);
}
}
else
{
if (slotStartAlignmentByteVal % frameStartAlignmentByteVal == 0)
{ return slotStartAlignmentByteVal; }
else
{
return std::max(
frameStartAlignmentByteVal, slotStartAlignmentByteVal);
}
}
}
void StagingBuffer::computeSlotStrideAndBufferSize()
{
// Slot stride is the maximum of alignment and padding
slotStrideNBytes = std::max(
inputConstraints.slotStartAlignmentByteVal,
inputConstraints.slotPadToNBytes);
// Calculate maximum alignment needed for first slot (must satisfy both frame and slot alignment)
size_t maxAlignment = calculateMaxAlignment(
inputConstraints.frameStartAlignmentByteVal,
inputConstraints.slotStartAlignmentByteVal);
// Calculate minimum buffer size
size_t minBufferSize = std::max(
inputConstraints.framePadToNBytes,
inputConstraints.slotPadToNBytes);
// Calculate total size needed for nDgramsPerFrame slots
size_t slotAreaSize = nDgramsPerFrame * slotStrideNBytes;
// Add padding space at buffer start for alignment offset (worst case: max alignment - 1)
size_t alignmentPadding = maxAlignment - 1;
// Total size needed: alignment padding + slot area, then ensure minimum is met
size_t rawSize = alignmentPadding + slotAreaSize;
if (rawSize < minBufferSize)
{ rawSize = minBufferSize; }
// Align up to the maximum alignment to ensure we can always find a valid offset
bufferNBytes = ((rawSize + maxAlignment - 1) / maxAlignment) * maxAlignment;
}
// Static member function to calculate offset and validate invariants
size_t StagingBuffer::calculateFirstSlotOffsetAndValidate(
uint8_t* buffer,
size_t bufferNBytes,
size_t nDgramsPerFrame,
size_t slotStrideNBytes,
const StagingBuffer::IOEngineConstraints& inputConstraints)
{
// Calculate maximum alignment needed for first slot
size_t maxAlignment = calculateMaxAlignment(
inputConstraints.frameStartAlignmentByteVal,
inputConstraints.slotStartAlignmentByteVal);
// Calculate offset to align first slot to both frame and slot alignment
uintptr_t bufferAddr = reinterpret_cast<uintptr_t>(buffer);
uintptr_t alignedAddr = ((bufferAddr + maxAlignment - 1) / maxAlignment)
* maxAlignment;
size_t firstSlotOffsetNBytes = alignedAddr - bufferAddr;
// Validate invariants with exceptions
uint8_t* firstSlotAddr = buffer + firstSlotOffsetNBytes;
if (
reinterpret_cast<uintptr_t>(firstSlotAddr)
% inputConstraints.frameStartAlignmentByteVal != 0)
{
throw std::runtime_error(std::string(__func__)
+ ": StagingBuffer: first slot address not aligned to "
+ std::to_string(inputConstraints.frameStartAlignmentByteVal));
}
if (
reinterpret_cast<uintptr_t>(firstSlotAddr)
% inputConstraints.slotStartAlignmentByteVal != 0)
{
throw std::runtime_error(std::string(__func__)
+ ": StagingBuffer: first slot address not aligned to "
+ std::to_string(inputConstraints.slotStartAlignmentByteVal));
}
size_t minBufferSize = std::max(
inputConstraints.framePadToNBytes,
inputConstraints.slotPadToNBytes);
if (bufferNBytes < minBufferSize)
{
throw std::runtime_error(std::string(__func__)
+ ": StagingBuffer: buffer size less than minimum required (max of "
+ std::to_string(inputConstraints.framePadToNBytes)
+ " and "
+ std::to_string(inputConstraints.slotPadToNBytes)
+ ")");
}
if (firstSlotOffsetNBytes + nDgramsPerFrame * slotStrideNBytes
> bufferNBytes)
{
throw std::runtime_error(std::string(__func__)
+ ": StagingBuffer: buffer size insufficient to hold "
+ std::to_string(nDgramsPerFrame)
+ " slots with proper alignment and padding");
}
return firstSlotOffsetNBytes;
}
StagingBuffer::StagingBuffer(
const IOEngineConstraints& inputEngineConstraints_,
const IOEngineConstraints& /*outputEngineConstraints*/,
size_t nDgramsPerFrame)
: buffer(nullptr, MmapDeleter(0)), bufferNBytes(0),
nDgramsPerFrame(nDgramsPerFrame), slotStrideNBytes(0),
firstSlotOffsetNBytes(0),
inputConstraints(inputEngineConstraints_),
assemblingFlag(false)
{
if (nDgramsPerFrame == 0)
{
throw std::invalid_argument(std::string(__func__)
+ ": StagingBuffer: nDgramsPerFrame must be > 0");
}
computeSlotStrideAndBufferSize();
/* Allocate buffer using mmap() for io_uring registration
* MAP_ANONYMOUS | MAP_PRIVATE creates anonymous, non-file-backed memory
*/
void* mmapped = mmap(
nullptr, bufferNBytes,
PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE,
-1, 0);
if (mmapped == MAP_FAILED)
{
throw std::runtime_error(std::string(__func__)
+ ": StagingBuffer: mmap() failed");
}
buffer = std::unique_ptr<uint8_t, MmapDeleter>(
static_cast<uint8_t*>(mmapped), MmapDeleter(bufferNBytes));
currentNBytes.store(0);
// Lock the buffer in memory to prevent swapping
if (mlock(buffer.get(), bufferNBytes) != 0)
{
throw std::runtime_error(std::string(__func__)
+ ": StagingBuffer: mlock() failed");
}
// Calculate offset and validate invariants (helper function in .cpp)
firstSlotOffsetNBytes = StagingBuffer::calculateFirstSlotOffsetAndValidate(
buffer.get(), bufferNBytes, nDgramsPerFrame,
slotStrideNBytes, inputConstraints);
// Build FrameAssemblyDesc once
std::vector<FrameAssemblyDesc::SlotDesc> slots;
slots.reserve(nDgramsPerFrame);
uint8_t *frameBase = buffer.get() + firstSlotOffsetNBytes;
for (size_t i = 0; i < nDgramsPerFrame; ++i)
{
size_t off = i * slotStrideNBytes;
FrameAssemblyDesc::SlotDesc s{
off, frameBase + off, inputConstraints.slotPadToNBytes};
slots.push_back(s);
}
frameDesc = std::make_shared<FrameAssemblyDesc>(
nDgramsPerFrame, inputConstraints.slotPadToNBytes, bufferNBytes,
std::move(slots));
}
} // namespace stim_buff
} // namespace smo
-185
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@@ -1,185 +0,0 @@
#ifndef STAGINGBUFFER_H
#define STAGINGBUFFER_H
#include <memory>
#include <cstdint>
#include <atomic>
#include <string>
#include <sstream>
#include <sys/mman.h>
#include <sys/uio.h>
#include "frameAssemblyDesc.h"
namespace smo {
namespace stim_buff {
/**
* StagingBuffer manages a large buffer to guide io_uring in assembling some
* number of Livox Avia pcloud UDP dgrams into a single stim frame.
*
* The buffer operates in a cycle:
* 1. io_uring assembles UDP dgrams into the buffer until it's full
* 2. Buffer is handed off to the stimbuff layer to be appended to the stimbuff.
* 3. When the stimbuff layer has appended the current assembled frame, the
* assembly buffer is reset and cycle repeats.
*/
class StagingBuffer
{
public:
class IOEngineConstraints
{
public:
IOEngineConstraints(
size_t slotStartAlignmentByteVal_,
size_t slotPadToNBytes_,
size_t frameStartAlignmentByteVal_,
size_t framePadToNBytes_)
: slotStartAlignmentByteVal(slotStartAlignmentByteVal_),
slotPadToNBytes(slotPadToNBytes_),
frameStartAlignmentByteVal(frameStartAlignmentByteVal_),
framePadToNBytes(framePadToNBytes_)
{}
~IOEngineConstraints() = default;
size_t slotStartAlignmentByteVal, slotPadToNBytes,
frameStartAlignmentByteVal, framePadToNBytes;
// Static defaults for io_uring and OpenCL
static const IOEngineConstraints ioUringConstraints;
static const IOEngineConstraints openClInputConstraints;
inline std::string stringify() const
{
std::ostringstream oss;
oss << "IOEngineConstraints{"
<< "slotStartAlignmentByteVal=" << slotStartAlignmentByteVal
<< ", slotPadToNBytes=" << slotPadToNBytes
<< ", frameStartAlignmentByteVal=" << frameStartAlignmentByteVal
<< ", framePadToNBytes=" << framePadToNBytes
<< "}";
return oss.str();
}
};
public:
/** EXPLANATION:
* We use the input and output engine constraints to determine the total
* amount of memory required internally to assemble a single frame with
* the given number of points per frame.
*/
explicit StagingBuffer(
const IOEngineConstraints& inputEngineConstraints,
const IOEngineConstraints& outputEngineConstraints,
size_t nDgramsPerFrame);
~StagingBuffer() = default;
// Non-copyable, movable
StagingBuffer(const StagingBuffer&) = delete;
StagingBuffer& operator=(const StagingBuffer&) = delete;
StagingBuffer(StagingBuffer&&) = default;
StagingBuffer& operator=(StagingBuffer&&) = default;
public:
/** EXPLANATION:
* Returns an input-engine-agnostic descriptor describing per-frame packet
* slot layout. Different input engines should be able to convert this into
* engine-specific metadata. E.g: io_uring's SQE descriptor.
*/
operator std::shared_ptr<FrameAssemblyDesc>() const { return frameDesc; }
// operator OpenClSharedBufferDescriptor() const;
bool isAssembling() const { return assemblingFlag.load(); }
void startAssembly() { assemblingFlag.store(true); }
void stopAssembly() { assemblingFlag.store(false); }
/** EXPLANATION:
* Returns an iovec for io_uring registration.
* The buffer is mmap()-allocated and suitable for IORING_REGISTER_BUFFERS.
*/
struct iovec getIoUringRegisterIoVec() const
{
struct iovec iov;
iov.iov_base = buffer.get();
iov.iov_len = bufferNBytes;
return iov;
}
/** EXPLANATION:
* Returns an iovec for OpenCL engine buffer access.
* The buffer is mmap()-allocated and suitable for CL_MEM_USE_HOST_PTR.
*/
struct iovec getClEngineIovec() const
{
struct iovec iov;
iov.iov_base = buffer.get();
iov.iov_len = bufferNBytes;
return iov;
}
inline std::string stringify() const
{
std::ostringstream oss;
oss << "StagingBuffer{"
<< "nDgramsPerFrame=" << nDgramsPerFrame
<< ", bufferNBytes=" << bufferNBytes
<< ", slotStrideNBytes=" << slotStrideNBytes
<< ", constraints=" << inputConstraints.stringify()
<< "}";
return oss.str();
}
private:
void computeSlotStrideAndBufferSize();
static size_t calculateFirstSlotOffsetAndValidate(
uint8_t* buffer,
size_t bufferNBytes,
size_t nDgramsPerFrame,
size_t slotStrideNBytes,
const IOEngineConstraints& inputConstraints);
// Custom deleter for mmap-allocated buffer
struct MmapDeleter
{
size_t size;
MmapDeleter(size_t s) : size(s) {}
void operator()(uint8_t* ptr) const
{
if (ptr != nullptr && size > 0)
{
munlock(ptr, size);
munmap(ptr, size);
}
}
};
// Buffer data - mmap-allocated for io_uring registration
// Using unique_ptr<uint8_t, MmapDeleter> instead of array syntax
// since we have a custom deleter that knows the size
std::unique_ptr<uint8_t, MmapDeleter> buffer;
size_t bufferNBytes;
// Layout/invariants
size_t nDgramsPerFrame;
public:
size_t slotStrideNBytes;
size_t firstSlotOffsetNBytes; // offset from buffer start to first slot
private:
IOEngineConstraints inputConstraints;
// Descriptor (computed once; reused across frames)
mutable std::shared_ptr<FrameAssemblyDesc> frameDesc;
// Current state
std::atomic<size_t> currentNBytes;
std::atomic<bool> assemblingFlag;
};
} // namespace stim_buff
} // namespace smo
#endif // STAGINGBUFFER_H