spike-v2: validate sync semantics (R1/R2 architectural review)

Architectural review (2026-05-15) указал что cudaStreamSynchronize-only на
producer-side не достаточен для cross-process visibility — NVIDIA Programming
Guide §3.2.8 требует cudaIpcEventHandle_t. Phase 0 PoC v1 не проверял этот
случай из-за cudaMemcpy который имеет implicit barriers.

spike-v2 воспроизводит правильный сценарий: consumer запускает verify_kernel
на ОТДЕЛЬНОМ stream'е (real-world use case — PyTorch / OpenCV CUDA), pattern
включает row-based component для отлова partial-frame torn.

Запуск 4 scenarios × 1500/600 frames:
  A-fhd60 (stream sync, FHD@60):  0 torn, p99=267µs, max=14.7ms
  B-fhd60 (event  sync, FHD@60):  0 torn, p99=344µs, max=5.2ms
  A-4k30  (stream sync, 4K@30):   0 torn, p99=606µs, max=4.4ms
  B-4k30  (event  sync, 4K@30):   0 torn, p99=437µs, max=3.7ms

Все 4 показали 0 torn frames. R1 на single-host single-GPU фактически
не воспроизводится — но NVIDIA contractually не гарантирует это.

Decision: events as default (R1/R2 resolved). Architecture.md §6.6 закрыт.
Tradeoff: mean latency +20µs, max latency в 3× ниже (predictable tail) +
future-proof для multi-GPU.

Также Dockerfile.dev — апдейт CUDA до 13.0.3 (12.4 не существует с devel-ubuntu24.04).

Связано с PR review: R1, R2, R3 (R3, R4 — в следующих коммитах).
This commit is contained in:
2026-05-14 23:00:13 +01:00
parent c2c2a9751a
commit ad543054fc
15 changed files with 663 additions and 2 deletions
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# Dev-окружение для cuframes — содержит CUDA toolkit (с nvcc), build tools,
# линкеры/анализаторы. GPU прокидывается через `--gpus all` на runtime.
#
# Base: nvidia/cuda devel-image c CUDA 12.4 + cuDNN 9 на Ubuntu 24.04.
# Base: nvidia/cuda devel-image c CUDA 13.0 + cuDNN на Ubuntu 24.04.
# devel-вариант (не runtime) — нужен для компиляции CUDA-кода (nvcc, headers).
# CUDA 13.x — текущая stable линейка с поддержкой sm_120 (Blackwell, RTX 5090).
FROM nvidia/cuda:12.4.1-cudnn-devel-ubuntu24.04
FROM nvidia/cuda:13.0.3-cudnn-devel-ubuntu24.04
# Не запрашивать tzdata interactive при apt
ENV DEBIAN_FRONTEND=noninteractive
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[consumer] key=A-4k30 count=600
[consumer] connected, 3840x2160 sync=stream
=== cuframes spike-v2 summary ===
scenario: A (stream sync)
frames received: 600
duration: 19.9625 s
effective fps: 30.0563
skipped (caught up): 0
TORN FRAMES: 0 ← ✓ clean
latency consumer-receive-to-kernel-done (microseconds):
mean: 164 us
p50: 145 us
p95: 206 us
p99: 606 us
max: 4412 us
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[consumer] key=A-fhd60 count=1500
[consumer] connected, 1920x1080 sync=stream
=== cuframes spike-v2 summary ===
scenario: A (stream sync)
frames received: 1500
duration: 24.9799 s
effective fps: 60.0482
skipped (caught up): 0
TORN FRAMES: 0 ← ✓ clean
latency consumer-receive-to-kernel-done (microseconds):
mean: 140 us
p50: 122 us
p95: 187 us
p99: 267 us
max: 14701 us
@@ -0,0 +1,18 @@
[consumer] key=B-4k30 count=600
[consumer] connected, 3840x2160 sync=event
[consumer] opened producer's cuda event
=== cuframes spike-v2 summary ===
scenario: B (event sync)
frames received: 600
duration: 19.9633 s
effective fps: 30.0552
skipped (caught up): 0
TORN FRAMES: 0 ← ✓ clean
latency consumer-receive-to-kernel-done (microseconds):
mean: 184 us
p50: 171 us
p95: 199 us
p99: 437 us
max: 3739 us
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[consumer] key=B-fhd60 count=1500
[consumer] connected, 1920x1080 sync=event
[consumer] opened producer's cuda event
=== cuframes spike-v2 summary ===
scenario: B (event sync)
frames received: 1500
duration: 24.9784 s
effective fps: 60.0518
skipped (caught up): 0
TORN FRAMES: 0 ← ✓ clean
latency consumer-receive-to-kernel-done (microseconds):
mean: 163 us
p50: 149 us
p95: 187 us
p99: 344 us
max: 5229 us
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cmake_minimum_required(VERSION 3.20)
project(cuframes_spike_v2 LANGUAGES CXX CUDA)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CUDA_STANDARD 17)
if(NOT DEFINED CMAKE_CUDA_ARCHITECTURES)
set(CMAKE_CUDA_ARCHITECTURES "120") # sm_120 для RTX 5090; добавьте 86/89/90 при необходимости
endif()
add_executable(spike2_producer producer.cu)
add_executable(spike2_consumer consumer.cu)
foreach(target spike2_producer spike2_consumer)
target_compile_options(${target} PRIVATE
$<$<COMPILE_LANGUAGE:CXX>:-Wall -Wextra -O2 -g>
$<$<COMPILE_LANGUAGE:CUDA>:-O2 -g -lineinfo>
)
target_link_libraries(${target} PRIVATE cuda)
endforeach()
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# Phase 0 spike-v2 — kernel-on-consumer-stream torn-frame test
Архитектор (review 2026-05-15) указал на **R1 / R2** в `docs/architecture.md`:
оригинальный PoC (`tools/spike/`) использовал `cudaMemcpy` на consumer-стороне,
который имеет implicit cross-context barriers. Это маскирует фундаментальную
проблему: **`cudaStreamSynchronize` на producer не достаточен** для гарантии
visibility GPU-writes для consumer'а на **отдельном stream'е**.
NVIDIA Programming Guide §3.2.8 явно говорит: «Synchronization between producer
and consumer processes is required and the responsibility of the application» —
то есть нужен `cudaIpcEventHandle_t` (cross-process CUDA event), не stream sync.
## Что проверяем
Два сценария:
### Сценарий A: stream sync only (текущий PoC v1 дизайн)
Producer:
- Fill_Y_kernel записывает `seq + row` в каждый пиксель строки `row` Y-plane
- `cudaStreamSynchronize(producer_stream)`
- Publish seq через atomic в SHM
Consumer:
- Read seq atomic ACQUIRE
- **Verify_kernel на consumer_stream'е** проверяет что Y-plane имеет ожидаемое
значение во **всех** строках. Если есть строка с другим значением → torn.
- `cudaDeviceSynchronize` чтобы kernel завершился, проверить result.
Ожидаем: torn frames на high-fps (60+) на FullHD или 4K.
### Сценарий B: event handle sync (предлагаемый fix)
Producer:
- `cudaEventCreateWithFlags(cudaEventInterprocess | cudaEventDisableTiming)`
- `cudaIpcGetEventHandle` → handle в SHM
- На каждый publish: `cudaEventRecord(event, producer_stream)` (вместо sync)
- Publish seq
Consumer:
- На subscribe: `cudaIpcOpenEventHandle` → local event
- На каждый next: `cudaStreamWaitEvent(consumer_stream, event, 0)` — GPU-side wait
- Verify_kernel на том же consumer_stream'е
- Result должен быть без torn frames даже на high resolution + high fps
## Acceptance
- A показал torn frames > 0 → R1 confirmed → нужны events
- B показал torn frames == 0 → R2 fix validated
- Latency B vs A — изменения не должно быть значимого (events = GPU-side wait, no CPU sync)
## Запуск (внутри cuframes-dev container)
```bash
cd /workspace
cmake -B build-v2 -S tools/spike-v2 -G Ninja
cmake --build build-v2
./tools/spike-v2/bench.sh
```
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#!/bin/bash
# Phase 0 spike-v2 — validate R1 (sync semantics).
# Runs both scenarios (A: stream sync, B: event sync) на 60 fps × FullHD.
# Если architecture's R1 правилен — Scenario A покажет torn frames > 0.
set -euo pipefail
cd "$(dirname "$0")/../.."
if [ ! -x build-v2/spike2_producer ]; then
echo "==> build first: cmake -B build-v2 -S tools/spike-v2 -G Ninja && cmake --build build-v2"
exit 1
fi
mkdir -p docs/measurements/spike-v2
run_scenario() {
local label="$1"
local sync="$2"
local fps="$3"
local res="$4"
local width="${res%x*}"
local height="${res#*x}"
local count="$5"
echo
echo "=== Scenario $label: sync=$sync, ${res}@${fps}fps, n=$count ==="
rm -f /dev/shm/cuframes-v2-* 2>/dev/null || true
./build-v2/spike2_producer \
--key "$label" --width "$width" --height "$height" \
--fps "$fps" --sync "$sync" --duration 60 \
> "docs/measurements/spike-v2/${label}-${sync}-${res}-${fps}fps-producer.log" 2>&1 &
local prod_pid=$!
sleep 1
./build-v2/spike2_consumer --key "$label" --count "$count" \
2>&1 | tee "docs/measurements/spike-v2/${label}-${sync}-${res}-${fps}fps-consumer.log" \
| tail -25 || true
kill "$prod_pid" 2>/dev/null || true
wait "$prod_pid" 2>/dev/null || true
}
run_scenario "A-fhd60" "stream" 60 "1920x1080" 1500
run_scenario "B-fhd60" "event" 60 "1920x1080" 1500
run_scenario "A-4k30" "stream" 30 "3840x2160" 600
run_scenario "B-4k30" "event" 30 "3840x2160" 600
echo
echo "=== Results stored in docs/measurements/spike-v2/ ==="
echo "=== Compare torn_frames count between A and B scenarios ==="
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// Phase 0 spike-v2 — общие типы. Расширенный относительно spike v1: добавлена
// поддержка cuda IPC event handle (для scenarios B) и pattern-fill per-row
// (для verify внутри кадра).
#pragma once
#include <cuda_runtime.h>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
namespace cuframes_spike_v2 {
constexpr int RING_SIZE = 2;
// Pattern: pixel [row][col] = (seq * 31 + row * 7) & 0xFF
// Использует разные значения по строкам — позволяет verify обнаружить если часть
// кадра ещё имеет старый seq.
__host__ __device__ inline uint8_t pattern_value(uint64_t seq, int row) {
return static_cast<uint8_t>((seq * 31u + row * 7u) & 0xFF);
}
struct FrameMeta {
int32_t width;
int32_t height;
int32_t pitch_y;
};
struct SlotDescriptor {
cudaIpcMemHandle_t mem_handle;
uint64_t producer_seq;
int64_t pts_ns;
};
struct SharedHeader {
uint32_t magic;
uint32_t version;
int32_t use_events; // 1 = sync mode B (events), 0 = sync mode A
cudaIpcEventHandle_t event_handle; // valid only if use_events == 1
FrameMeta meta;
SlotDescriptor slots[RING_SIZE];
uint64_t global_seq;
// Diagnostics
uint64_t torn_frame_count; // consumer записывает; producer читает для лога
};
constexpr uint32_t MAGIC = 0xCC7C2D02u;
constexpr uint32_t VERSION = 2;
#define CHECK_CUDA(call) do { \
cudaError_t _err = (call); \
if (_err != cudaSuccess) { \
fprintf(stderr, "CUDA error at %s:%d: %s\n", \
__FILE__, __LINE__, cudaGetErrorString(_err)); \
std::exit(1); \
} \
} while (0)
static inline int64_t now_ns() {
timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return static_cast<int64_t>(ts.tv_sec) * 1000000000LL + ts.tv_nsec;
}
} // namespace cuframes_spike_v2
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// spike-v2 consumer.
//
// КЛЮЧЕВОЕ отличие от v1: verify работает через CUDA kernel на ОТДЕЛЬНОМ
// (consumer'ском) stream'е, а не через cudaMemcpy. Это правильно эмулирует
// real-world consumer (PyTorch, OpenCV CUDA) и проверяет sync semantics.
//
// Scenario A (--sync=stream): должны быть torn frames на high-fps
// Scenario B (--sync=event): torn frames должны быть 0
#include "common.h"
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <algorithm>
#include <chrono>
#include <iostream>
#include <string>
#include <thread>
#include <vector>
using namespace cuframes_spike_v2;
// Verify kernel: проверяет что каждая строка имеет pattern(seq, row).
// Записывает кол-во несовпадающих байтов в out_bad_count.
__global__ void verify_pattern(const uint8_t* y, int width, int height,
int pitch_y, uint64_t expected_seq,
int* out_bad_count) {
int x = blockIdx.x * blockDim.x + threadIdx.x;
int row = blockIdx.y * blockDim.y + threadIdx.y;
if (x < width && row < height) {
uint8_t expect = pattern_value(expected_seq, row);
uint8_t actual = y[row * pitch_y + x];
if (actual != expect) {
atomicAdd(out_bad_count, 1);
}
}
}
struct Args {
std::string key = "A";
int count = 500;
};
static Args parse_args(int argc, char** argv) {
Args a;
for (int i = 1; i < argc; ++i) {
std::string arg = argv[i];
auto next = [&] { return std::string(argv[++i]); };
if (arg == "--key") a.key = next();
else if (arg == "--count") a.count = std::stoi(next());
}
return a;
}
int main(int argc, char** argv) {
Args args = parse_args(argc, argv);
std::cout << "[consumer] key=" << args.key << " count=" << args.count << "\n";
CHECK_CUDA(cudaSetDevice(0));
// Open SHM
std::string shm_path = "/dev/shm/cuframes-v2-" + args.key;
int fd = -1;
for (int retry = 0; retry < 50; ++retry) {
fd = open(shm_path.c_str(), O_RDWR);
if (fd >= 0) break;
std::this_thread::sleep_for(std::chrono::milliseconds(100));
}
if (fd < 0) {
std::cerr << "[consumer] no producer at " << shm_path << "\n";
return 1;
}
auto* shared = static_cast<SharedHeader*>(
mmap(nullptr, sizeof(SharedHeader), PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0));
if (shared == MAP_FAILED) { perror("[consumer] mmap"); return 1; }
close(fd);
if (shared->magic != MAGIC || shared->version != VERSION) {
std::cerr << "[consumer] protocol mismatch magic=" << std::hex
<< shared->magic << " ver=" << shared->version << "\n";
return 1;
}
bool use_events = shared->use_events != 0;
std::cout << "[consumer] connected, " << shared->meta.width
<< "x" << shared->meta.height
<< " sync=" << (use_events ? "event" : "stream") << "\n";
// Map producer's memory
void* slot_ptrs[RING_SIZE];
for (int i = 0; i < RING_SIZE; ++i) {
CHECK_CUDA(cudaIpcOpenMemHandle(&slot_ptrs[i],
shared->slots[i].mem_handle,
cudaIpcMemLazyEnablePeerAccess));
}
// Map producer's event если sync=event
cudaEvent_t producer_event = nullptr;
if (use_events) {
CHECK_CUDA(cudaIpcOpenEventHandle(&producer_event,
shared->event_handle));
std::cout << "[consumer] opened producer's cuda event\n";
}
// Consumer's own stream — это и есть ключевой момент.
cudaStream_t consumer_stream;
CHECK_CUDA(cudaStreamCreate(&consumer_stream));
// Counter в device memory для verify_pattern kernel
int* d_bad_count;
CHECK_CUDA(cudaMalloc(&d_bad_count, sizeof(int)));
const int width = shared->meta.width;
const int height = shared->meta.height;
const int pitch_y = shared->meta.pitch_y;
dim3 block(32, 8);
dim3 grid((width + block.x - 1) / block.x,
(height + block.y - 1) / block.y);
std::vector<int64_t> latencies_ns;
latencies_ns.reserve(args.count);
uint64_t last_seen = UINT64_MAX;
int frames_received = 0;
int torn_frames = 0;
int skipped_frames = 0;
auto t_start = std::chrono::steady_clock::now();
while (frames_received < args.count) {
uint64_t seq = __atomic_load_n(&shared->global_seq, __ATOMIC_ACQUIRE);
if (seq == last_seen ||
(last_seen == UINT64_MAX && seq == 0 &&
__atomic_load_n(&shared->slots[0].producer_seq, __ATOMIC_ACQUIRE) == 0)) {
std::this_thread::sleep_for(std::chrono::microseconds(50));
continue;
}
if (last_seen != UINT64_MAX && seq > last_seen + 1) {
skipped_frames += (seq - last_seen - 1);
}
last_seen = seq;
const int slot_idx = seq % RING_SIZE;
const int64_t pts_ns = __atomic_load_n(&shared->slots[slot_idx].pts_ns,
__ATOMIC_ACQUIRE);
// *** КЛЮЧЕВОЕ ***
// Если используем events — wait на producer's event перед kernel'ом.
// Если stream-only sync — НЕ ждём (consumer не знает producer's stream).
if (use_events) {
CHECK_CUDA(cudaStreamWaitEvent(consumer_stream, producer_event, 0));
}
// Reset bad_count + verify kernel на consumer_stream
CHECK_CUDA(cudaMemsetAsync(d_bad_count, 0, sizeof(int), consumer_stream));
verify_pattern<<<grid, block, 0, consumer_stream>>>(
static_cast<const uint8_t*>(slot_ptrs[slot_idx]),
width, height, pitch_y, seq, d_bad_count);
// Получить result (это синхронизирует consumer_stream)
int bad_count = 0;
CHECK_CUDA(cudaMemcpyAsync(&bad_count, d_bad_count, sizeof(int),
cudaMemcpyDeviceToHost, consumer_stream));
CHECK_CUDA(cudaStreamSynchronize(consumer_stream));
const int64_t recv_ns = now_ns();
const int64_t latency_ns = recv_ns - pts_ns;
if (bad_count > 0) {
torn_frames++;
// Записать в SHM чтобы producer тоже видел
__atomic_fetch_add(&shared->torn_frame_count, 1, __ATOMIC_RELEASE);
}
latencies_ns.push_back(latency_ns);
frames_received++;
}
auto t_end = std::chrono::steady_clock::now();
double duration_sec = std::chrono::duration<double>(t_end - t_start).count();
for (int i = 0; i < RING_SIZE; ++i) {
CHECK_CUDA(cudaIpcCloseMemHandle(slot_ptrs[i]));
}
if (producer_event) cudaEventDestroy(producer_event);
cudaFree(d_bad_count);
cudaStreamDestroy(consumer_stream);
munmap(shared, sizeof(SharedHeader));
std::sort(latencies_ns.begin(), latencies_ns.end());
auto pct = [&](double p) -> int64_t {
return latencies_ns[static_cast<size_t>(latencies_ns.size() * p)];
};
int64_t sum = 0;
for (auto v : latencies_ns) sum += v;
std::cout << "\n=== cuframes spike-v2 summary ===\n";
std::cout << "scenario: " << (use_events ? "B (event sync)" : "A (stream sync)") << "\n";
std::cout << "frames received: " << frames_received << "\n";
std::cout << "duration: " << duration_sec << " s\n";
std::cout << "effective fps: " << frames_received / duration_sec << "\n";
std::cout << "skipped (caught up): " << skipped_frames << "\n";
std::cout << "TORN FRAMES: " << torn_frames
<< " ← " << (torn_frames == 0 ? "✓ clean" : "✗ DATA RACE!") << "\n";
std::cout << "\nlatency consumer-receive-to-kernel-done (microseconds):\n";
std::cout << " mean: " << sum / 1000 / latencies_ns.size() << " us\n";
std::cout << " p50: " << pct(0.50) / 1000 << " us\n";
std::cout << " p95: " << pct(0.95) / 1000 << " us\n";
std::cout << " p99: " << pct(0.99) / 1000 << " us\n";
std::cout << " max: " << latencies_ns.back() / 1000 << " us\n";
return torn_frames == 0 ? 0 : 2;
}
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// spike-v2 producer.
//
// В отличие от spike v1: pattern зависит от (seq, row) — каждая строка пишется
// своим значением. Если у consumer'а проявятся torn frames, они будут видны
// как «строки с разным seq» в одном кадре.
//
// Опция --sync=stream → cudaStreamSynchronize (Scenario A, текущий дизайн)
// Опция --sync=event → cudaIpcEvent (Scenario B, предлагаемый fix)
//
// Usage:
// ./producer --key A --width 1920 --height 1080 --fps 60 --sync stream
// ./producer --key B --width 1920 --height 1080 --fps 60 --sync event
#include "common.h"
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <chrono>
#include <iostream>
#include <string>
#include <thread>
using namespace cuframes_spike_v2;
// Kernel: каждая строка получает значение pattern_value(seq, row)
__global__ void fill_pattern(uint8_t* y, int width, int height, int pitch_y,
uint64_t seq) {
int x = blockIdx.x * blockDim.x + threadIdx.x;
int row = blockIdx.y * blockDim.y + threadIdx.y;
if (x < width && row < height) {
uint8_t v = pattern_value(seq, row);
y[row * pitch_y + x] = v;
}
}
struct Args {
std::string key = "A";
int width = 1920;
int height = 1080;
int fps = 60;
int duration_sec = 0;
std::string sync = "stream"; // "stream" | "event"
};
static Args parse_args(int argc, char** argv) {
Args a;
for (int i = 1; i < argc; ++i) {
std::string arg = argv[i];
auto next = [&] { return std::string(argv[++i]); };
if (arg == "--key") a.key = next();
else if (arg == "--width") a.width = std::stoi(next());
else if (arg == "--height") a.height = std::stoi(next());
else if (arg == "--fps") a.fps = std::stoi(next());
else if (arg == "--duration") a.duration_sec = std::stoi(next());
else if (arg == "--sync") a.sync = next();
}
return a;
}
int main(int argc, char** argv) {
Args args = parse_args(argc, argv);
bool use_events = (args.sync == "event");
std::cout << "[producer] key=" << args.key
<< " " << args.width << "x" << args.height
<< " @ " << args.fps << " fps"
<< " sync=" << args.sync << "\n";
CHECK_CUDA(cudaSetDevice(0));
const int pitch_y = args.width;
const size_t y_bytes = static_cast<size_t>(pitch_y) * args.height;
void* slot_ptrs[RING_SIZE];
cudaIpcMemHandle_t slot_handles[RING_SIZE];
for (int i = 0; i < RING_SIZE; ++i) {
CHECK_CUDA(cudaMalloc(&slot_ptrs[i], y_bytes));
CHECK_CUDA(cudaIpcGetMemHandle(&slot_handles[i], slot_ptrs[i]));
}
// Create event for cross-process sync (Scenario B)
cudaEvent_t event = nullptr;
cudaIpcEventHandle_t event_handle = {};
if (use_events) {
CHECK_CUDA(cudaEventCreateWithFlags(&event,
cudaEventDisableTiming | cudaEventInterprocess));
CHECK_CUDA(cudaIpcGetEventHandle(&event_handle, event));
std::cout << "[producer] cuda event for IPC sync created\n";
}
// POSIX shm
std::string shm_path = "/dev/shm/cuframes-v2-" + args.key;
int fd = open(shm_path.c_str(), O_CREAT | O_RDWR, 0666);
if (fd < 0 || ftruncate(fd, sizeof(SharedHeader)) < 0) {
perror("[producer] shm");
return 1;
}
auto* shared = static_cast<SharedHeader*>(
mmap(nullptr, sizeof(SharedHeader), PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0));
if (shared == MAP_FAILED) {
perror("[producer] mmap");
return 1;
}
std::memset(shared, 0, sizeof(SharedHeader));
shared->magic = MAGIC;
shared->version = VERSION;
shared->use_events = use_events ? 1 : 0;
if (use_events) shared->event_handle = event_handle;
shared->meta = {args.width, args.height, pitch_y};
for (int i = 0; i < RING_SIZE; ++i) {
shared->slots[i].mem_handle = slot_handles[i];
}
__atomic_thread_fence(__ATOMIC_RELEASE);
std::cout << "[producer] shm ready at " << shm_path << "\n";
cudaStream_t stream;
CHECK_CUDA(cudaStreamCreate(&stream));
const auto frame_interval = std::chrono::nanoseconds(1'000'000'000LL / args.fps);
auto next_frame = std::chrono::steady_clock::now();
dim3 block(32, 8);
dim3 grid((args.width + block.x - 1) / block.x,
(args.height + block.y - 1) / block.y);
uint64_t seq = 0;
const int64_t end_ns = args.duration_sec > 0
? now_ns() + args.duration_sec * 1'000'000'000LL : 0;
while (true) {
if (end_ns && now_ns() > end_ns) break;
const int slot_idx = seq % RING_SIZE;
// Заполнить slot pattern'ом
fill_pattern<<<grid, block, 0, stream>>>(
static_cast<uint8_t*>(slot_ptrs[slot_idx]),
args.width, args.height, pitch_y, seq);
// Sync: либо stream sync (Scenario A), либо event record (Scenario B)
if (use_events) {
CHECK_CUDA(cudaEventRecord(event, stream));
// НЕ делаем cudaStreamSynchronize — consumer сам wait'нет event
} else {
CHECK_CUDA(cudaStreamSynchronize(stream));
}
// Publish (атомарный seq bump после sync/record)
__atomic_store_n(&shared->slots[slot_idx].producer_seq, seq, __ATOMIC_RELEASE);
__atomic_store_n(&shared->slots[slot_idx].pts_ns, now_ns(), __ATOMIC_RELEASE);
__atomic_store_n(&shared->global_seq, seq, __ATOMIC_RELEASE);
if (seq % 300 == 0 && seq > 0) {
uint64_t torn = __atomic_load_n(&shared->torn_frame_count, __ATOMIC_ACQUIRE);
std::cout << "[producer] seq=" << seq << " torn_frames_so_far=" << torn << "\n";
}
seq++;
next_frame += frame_interval;
std::this_thread::sleep_until(next_frame);
}
uint64_t torn_final = __atomic_load_n(&shared->torn_frame_count, __ATOMIC_ACQUIRE);
std::cout << "[producer] FINAL: published=" << seq
<< " torn_frames=" << torn_final << "\n";
for (int i = 0; i < RING_SIZE; ++i) CHECK_CUDA(cudaFree(slot_ptrs[i]));
if (event) cudaEventDestroy(event);
munmap(shared, sizeof(SharedHeader));
close(fd);
unlink(shm_path.c_str());
return 0;
}