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Apply consistent code formatting across the repo. Add clang-format and pre-commit hooks.

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Rob Armstrong
2025-03-27 10:30:07 -07:00
parent 2cd58fbc9a
commit ceab6e8bcc
782 changed files with 107230 additions and 106548 deletions
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1
Samples/0_Introduction/simpleIPC/README.md
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@@ -34,4 +34,3 @@ Download and install the [CUDA Toolkit 12.5](https://developer.nvidia.com/cuda-d
Make sure the dependencies mentioned in [Dependencies]() section above are installed.
## References (for more details)

486
Samples/0_Introduction/simpleIPC/simpleIPC.cu
View File

@@ -32,6 +32,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include "helper_cuda.h"
#include "helper_multiprocess.h"
static const char shmName[] = "simpleIPCshm";
@@ -39,7 +40,7 @@ static const char shmName[] = "simpleIPCshm";
// For NVSWITCH connected peers like DGX-2, simultaneous peers are not limited
// in the same way.
#define MAX_DEVICES (32)
#define DATA_SIZE (64ULL << 20ULL) // 64MB
#define DATA_SIZE (64ULL << 20ULL) // 64MB
#if defined(__linux__)
#define cpu_atomic_add32(a, x) __sync_add_and_fetch(a, x)
@@ -49,281 +50,280 @@ static const char shmName[] = "simpleIPCshm";
#error Unsupported system
#endif
typedef struct shmStruct_st {
size_t nprocesses;
int barrier;
int sense;
int devices[MAX_DEVICES];
cudaIpcMemHandle_t memHandle[MAX_DEVICES];
cudaIpcEventHandle_t eventHandle[MAX_DEVICES];
typedef struct shmStruct_st
{
size_t nprocesses;
int barrier;
int sense;
int devices[MAX_DEVICES];
cudaIpcMemHandle_t memHandle[MAX_DEVICES];
cudaIpcEventHandle_t eventHandle[MAX_DEVICES];
} shmStruct;
__global__ void simpleKernel(char *ptr, int sz, char val) {
int idx = blockIdx.x * blockDim.x + threadIdx.x;
for (; idx < sz; idx += (gridDim.x * blockDim.x)) {
ptr[idx] = val;
}
__global__ void simpleKernel(char *ptr, int sz, char val)
{
int idx = blockIdx.x * blockDim.x + threadIdx.x;
for (; idx < sz; idx += (gridDim.x * blockDim.x)) {
ptr[idx] = val;
}
}
static void barrierWait(volatile int *barrier, volatile int *sense,
unsigned int n) {
int count;
static void barrierWait(volatile int *barrier, volatile int *sense, unsigned int n)
{
int count;
// Check-in
count = cpu_atomic_add32(barrier, 1);
if (count == n) // Last one in
*sense = 1;
while (!*sense)
;
// Check-in
count = cpu_atomic_add32(barrier, 1);
if (count == n) // Last one in
*sense = 1;
while (!*sense)
;
// Check-out
count = cpu_atomic_add32(barrier, -1);
if (count == 0) // Last one out
*sense = 0;
while (*sense)
;
// Check-out
count = cpu_atomic_add32(barrier, -1);
if (count == 0) // Last one out
*sense = 0;
while (*sense)
;
}
static void childProcess(int id) {
volatile shmStruct *shm = NULL;
cudaStream_t stream;
sharedMemoryInfo info;
size_t procCount, i;
int blocks = 0;
int threads = 128;
cudaDeviceProp prop;
std::vector<void *> ptrs;
std::vector<cudaEvent_t> events;
std::vector<char> verification_buffer(DATA_SIZE);
static void childProcess(int id)
{
volatile shmStruct *shm = NULL;
cudaStream_t stream;
sharedMemoryInfo info;
size_t procCount, i;
int blocks = 0;
int threads = 128;
cudaDeviceProp prop;
std::vector<void *> ptrs;
std::vector<cudaEvent_t> events;
std::vector<char> verification_buffer(DATA_SIZE);
if (sharedMemoryOpen(shmName, sizeof(shmStruct), &info) != 0) {
printf("Failed to create shared memory slab\n");
exit(EXIT_FAILURE);
}
shm = (volatile shmStruct *)info.addr;
procCount = shm->nprocesses;
printf("Process %d: Starting on device %d...\n", id, shm->devices[id]);
checkCudaErrors(cudaSetDevice(shm->devices[id]));
checkCudaErrors(cudaGetDeviceProperties(&prop, shm->devices[id]));
checkCudaErrors(cudaStreamCreateWithFlags(&stream, cudaStreamNonBlocking));
checkCudaErrors(cudaOccupancyMaxActiveBlocksPerMultiprocessor(
&blocks, simpleKernel, threads, 0));
blocks *= prop.multiProcessorCount;
// Open and track all the allocations and events created in the master
// process for use later
for (i = 0; i < procCount; i++) {
void *ptr = NULL;
cudaEvent_t event;
// Notice, we don't need to explicitly enable peer access for
// allocations on other devices.
checkCudaErrors(
cudaIpcOpenMemHandle(&ptr, *(cudaIpcMemHandle_t *)&shm->memHandle[i],
cudaIpcMemLazyEnablePeerAccess));
checkCudaErrors(cudaIpcOpenEventHandle(
&event, *(cudaIpcEventHandle_t *)&shm->eventHandle[i]));
ptrs.push_back(ptr);
events.push_back(event);
}
// At each iteration of the loop, each sibling process will push work on
// their respective devices accessing the next peer mapped buffer allocated
// by the master process (these can come from other sibling processes as
// well). To coordinate each process' access, we force the stream to wait for
// the work already accessing this buffer asynchronously through IPC events,
// allowing the CPU processes to continue to queue more work.
for (i = 0; i < procCount; i++) {
size_t bufferId = (i + id) % procCount;
// Wait for the buffer to be accessed to be ready
checkCudaErrors(cudaStreamWaitEvent(stream, events[bufferId], 0));
// Push a simple kernel on it
simpleKernel<<<blocks, threads, 0, stream>>>((char *)ptrs[bufferId],
DATA_SIZE, id);
checkCudaErrors(cudaGetLastError());
// Signal that this buffer is ready for the next consumer
checkCudaErrors(cudaEventRecord(events[bufferId], stream));
// Wait for all my sibling processes to push this stage of their work
// before proceeding to the next. This prevents siblings from racing
// ahead and clobbering the recorded event or waiting on the wrong
// recorded event.
barrierWait(&shm->barrier, &shm->sense, (unsigned int)procCount);
if (id == 0) {
printf("Step %lld done\n", (unsigned long long)i);
if (sharedMemoryOpen(shmName, sizeof(shmStruct), &info) != 0) {
printf("Failed to create shared memory slab\n");
exit(EXIT_FAILURE);
}
}
shm = (volatile shmStruct *)info.addr;
procCount = shm->nprocesses;
// Now wait for my buffer to be ready so I can copy it locally and verify it
checkCudaErrors(cudaStreamWaitEvent(stream, events[id], 0));
checkCudaErrors(cudaMemcpyAsync(&verification_buffer[0], ptrs[id], DATA_SIZE,
cudaMemcpyDeviceToHost, stream));
// And wait for all the queued up work to complete
checkCudaErrors(cudaStreamSynchronize(stream));
printf("Process %d: Starting on device %d...\n", id, shm->devices[id]);
printf("Process %d: verifying...\n", id);
checkCudaErrors(cudaSetDevice(shm->devices[id]));
checkCudaErrors(cudaGetDeviceProperties(&prop, shm->devices[id]));
checkCudaErrors(cudaStreamCreateWithFlags(&stream, cudaStreamNonBlocking));
checkCudaErrors(cudaOccupancyMaxActiveBlocksPerMultiprocessor(&blocks, simpleKernel, threads, 0));
blocks *= prop.multiProcessorCount;
// The contents should have the id of the sibling just after me
char compareId = (char)((id + 1) % procCount);
for (unsigned long long j = 0; j < DATA_SIZE; j++) {
if (verification_buffer[j] != compareId) {
printf("Process %d: Verification mismatch at %lld: %d != %d\n", id, j,
(int)verification_buffer[j], (int)compareId);
// Open and track all the allocations and events created in the master
// process for use later
for (i = 0; i < procCount; i++) {
void *ptr = NULL;
cudaEvent_t event;
// Notice, we don't need to explicitly enable peer access for
// allocations on other devices.
checkCudaErrors(
cudaIpcOpenMemHandle(&ptr, *(cudaIpcMemHandle_t *)&shm->memHandle[i], cudaIpcMemLazyEnablePeerAccess));
checkCudaErrors(cudaIpcOpenEventHandle(&event, *(cudaIpcEventHandle_t *)&shm->eventHandle[i]));
ptrs.push_back(ptr);
events.push_back(event);
}
}
// Clean up!
for (i = 0; i < procCount; i++) {
checkCudaErrors(cudaIpcCloseMemHandle(ptrs[i]));
checkCudaErrors(cudaEventDestroy(events[i]));
}
// At each iteration of the loop, each sibling process will push work on
// their respective devices accessing the next peer mapped buffer allocated
// by the master process (these can come from other sibling processes as
// well). To coordinate each process' access, we force the stream to wait for
// the work already accessing this buffer asynchronously through IPC events,
// allowing the CPU processes to continue to queue more work.
for (i = 0; i < procCount; i++) {
size_t bufferId = (i + id) % procCount;
// Wait for the buffer to be accessed to be ready
checkCudaErrors(cudaStreamWaitEvent(stream, events[bufferId], 0));
// Push a simple kernel on it
simpleKernel<<<blocks, threads, 0, stream>>>((char *)ptrs[bufferId], DATA_SIZE, id);
checkCudaErrors(cudaGetLastError());
// Signal that this buffer is ready for the next consumer
checkCudaErrors(cudaEventRecord(events[bufferId], stream));
// Wait for all my sibling processes to push this stage of their work
// before proceeding to the next. This prevents siblings from racing
// ahead and clobbering the recorded event or waiting on the wrong
// recorded event.
barrierWait(&shm->barrier, &shm->sense, (unsigned int)procCount);
if (id == 0) {
printf("Step %lld done\n", (unsigned long long)i);
}
}
checkCudaErrors(cudaStreamDestroy(stream));
// Now wait for my buffer to be ready so I can copy it locally and verify it
checkCudaErrors(cudaStreamWaitEvent(stream, events[id], 0));
checkCudaErrors(cudaMemcpyAsync(&verification_buffer[0], ptrs[id], DATA_SIZE, cudaMemcpyDeviceToHost, stream));
// And wait for all the queued up work to complete
checkCudaErrors(cudaStreamSynchronize(stream));
printf("Process %d complete!\n", id);
printf("Process %d: verifying...\n", id);
// The contents should have the id of the sibling just after me
char compareId = (char)((id + 1) % procCount);
for (unsigned long long j = 0; j < DATA_SIZE; j++) {
if (verification_buffer[j] != compareId) {
printf("Process %d: Verification mismatch at %lld: %d != %d\n",
id,
j,
(int)verification_buffer[j],
(int)compareId);
}
}
// Clean up!
for (i = 0; i < procCount; i++) {
checkCudaErrors(cudaIpcCloseMemHandle(ptrs[i]));
checkCudaErrors(cudaEventDestroy(events[i]));
}
checkCudaErrors(cudaStreamDestroy(stream));
printf("Process %d complete!\n", id);
}
static void parentProcess(char *app) {
sharedMemoryInfo info;
int devCount, i;
volatile shmStruct *shm = NULL;
std::vector<void *> ptrs;
std::vector<cudaEvent_t> events;
std::vector<Process> processes;
static void parentProcess(char *app)
{
sharedMemoryInfo info;
int devCount, i;
volatile shmStruct *shm = NULL;
std::vector<void *> ptrs;
std::vector<cudaEvent_t> events;
std::vector<Process> processes;
checkCudaErrors(cudaGetDeviceCount(&devCount));
checkCudaErrors(cudaGetDeviceCount(&devCount));
if (sharedMemoryCreate(shmName, sizeof(*shm), &info) != 0) {
printf("Failed to create shared memory slab\n");
exit(EXIT_FAILURE);
}
shm = (volatile shmStruct *)info.addr;
memset((void *)shm, 0, sizeof(*shm));
// Pick all the devices that can access each other's memory for this test
// Keep in mind that CUDA has minimal support for fork() without a
// corresponding exec() in the child process, but in this case our
// spawnProcess will always exec, so no need to worry.
for (i = 0; i < devCount; i++) {
bool allPeers = true;
cudaDeviceProp prop;
checkCudaErrors(cudaGetDeviceProperties(&prop, i));
// CUDA IPC is only supported on devices with unified addressing
if (!prop.unifiedAddressing) {
printf("Device %d does not support unified addressing, skipping...\n", i);
continue;
if (sharedMemoryCreate(shmName, sizeof(*shm), &info) != 0) {
printf("Failed to create shared memory slab\n");
exit(EXIT_FAILURE);
}
// This sample requires two processes accessing each device, so we need
// to ensure exclusive or prohibited mode is not set
if (prop.computeMode != cudaComputeModeDefault) {
printf("Device %d is in an unsupported compute mode for this sample\n",
i);
continue;
shm = (volatile shmStruct *)info.addr;
memset((void *)shm, 0, sizeof(*shm));
// Pick all the devices that can access each other's memory for this test
// Keep in mind that CUDA has minimal support for fork() without a
// corresponding exec() in the child process, but in this case our
// spawnProcess will always exec, so no need to worry.
for (i = 0; i < devCount; i++) {
bool allPeers = true;
cudaDeviceProp prop;
checkCudaErrors(cudaGetDeviceProperties(&prop, i));
// CUDA IPC is only supported on devices with unified addressing
if (!prop.unifiedAddressing) {
printf("Device %d does not support unified addressing, skipping...\n", i);
continue;
}
// This sample requires two processes accessing each device, so we need
// to ensure exclusive or prohibited mode is not set
if (prop.computeMode != cudaComputeModeDefault) {
printf("Device %d is in an unsupported compute mode for this sample\n", i);
continue;
}
for (int j = 0; j < shm->nprocesses; j++) {
int canAccessPeerIJ, canAccessPeerJI;
checkCudaErrors(cudaDeviceCanAccessPeer(&canAccessPeerJI, shm->devices[j], i));
checkCudaErrors(cudaDeviceCanAccessPeer(&canAccessPeerIJ, i, shm->devices[j]));
if (!canAccessPeerIJ || !canAccessPeerJI) {
allPeers = false;
break;
}
}
if (allPeers) {
// Enable peers here. This isn't necessary for IPC, but it will
// setup the peers for the device. For systems that only allow 8
// peers per GPU at a time, this acts to remove devices from CanAccessPeer
for (int j = 0; j < shm->nprocesses; j++) {
checkCudaErrors(cudaSetDevice(i));
checkCudaErrors(cudaDeviceEnablePeerAccess(shm->devices[j], 0));
checkCudaErrors(cudaSetDevice(shm->devices[j]));
checkCudaErrors(cudaDeviceEnablePeerAccess(i, 0));
}
shm->devices[shm->nprocesses++] = i;
if (shm->nprocesses >= MAX_DEVICES)
break;
}
else {
printf("Device %d is not peer capable with some other selected peers, "
"skipping\n",
i);
}
}
for (int j = 0; j < shm->nprocesses; j++) {
int canAccessPeerIJ, canAccessPeerJI;
checkCudaErrors(
cudaDeviceCanAccessPeer(&canAccessPeerJI, shm->devices[j], i));
checkCudaErrors(
cudaDeviceCanAccessPeer(&canAccessPeerIJ, i, shm->devices[j]));
if (!canAccessPeerIJ || !canAccessPeerJI) {
allPeers = false;
break;
}
}
if (allPeers) {
// Enable peers here. This isn't necessary for IPC, but it will
// setup the peers for the device. For systems that only allow 8
// peers per GPU at a time, this acts to remove devices from CanAccessPeer
for (int j = 0; j < shm->nprocesses; j++) {
checkCudaErrors(cudaSetDevice(i));
checkCudaErrors(cudaDeviceEnablePeerAccess(shm->devices[j], 0));
checkCudaErrors(cudaSetDevice(shm->devices[j]));
checkCudaErrors(cudaDeviceEnablePeerAccess(i, 0));
}
shm->devices[shm->nprocesses++] = i;
if (shm->nprocesses >= MAX_DEVICES) break;
} else {
printf(
"Device %d is not peer capable with some other selected peers, "
"skipping\n",
i);
}
}
if (shm->nprocesses == 0) {
printf("No CUDA devices support IPC\n");
exit(EXIT_WAIVED);
}
// Now allocate memory and an event for each process and fill the shared
// memory buffer with the IPC handles to communicate
for (i = 0; i < shm->nprocesses; i++) {
void *ptr = NULL;
cudaEvent_t event;
checkCudaErrors(cudaSetDevice(shm->devices[i]));
checkCudaErrors(cudaMalloc(&ptr, DATA_SIZE));
checkCudaErrors(
cudaIpcGetMemHandle((cudaIpcMemHandle_t *)&shm->memHandle[i], ptr));
checkCudaErrors(cudaEventCreate(
&event, cudaEventDisableTiming | cudaEventInterprocess));
checkCudaErrors(cudaIpcGetEventHandle(
(cudaIpcEventHandle_t *)&shm->eventHandle[i], event));
ptrs.push_back(ptr);
events.push_back(event);
}
// Launch the child processes!
for (i = 0; i < shm->nprocesses; i++) {
char devIdx[12]; // Increased size to ensure enough space for formatted integer
char *const args[] = {app, devIdx, NULL};
Process process;
snprintf(devIdx, sizeof(devIdx), "%d", i);
if (spawnProcess(&process, app, args)) {
printf("Failed to create process\n");
exit(EXIT_FAILURE);
if (shm->nprocesses == 0) {
printf("No CUDA devices support IPC\n");
exit(EXIT_WAIVED);
}
processes.push_back(process);
}
// Now allocate memory and an event for each process and fill the shared
// memory buffer with the IPC handles to communicate
for (i = 0; i < shm->nprocesses; i++) {
void *ptr = NULL;
cudaEvent_t event;
// And wait for them to finish
for (i = 0; i < processes.size(); i++) {
if (waitProcess(&processes[i]) != EXIT_SUCCESS) {
printf("Process %d failed!\n", i);
exit(EXIT_FAILURE);
checkCudaErrors(cudaSetDevice(shm->devices[i]));
checkCudaErrors(cudaMalloc(&ptr, DATA_SIZE));
checkCudaErrors(cudaIpcGetMemHandle((cudaIpcMemHandle_t *)&shm->memHandle[i], ptr));
checkCudaErrors(cudaEventCreate(&event, cudaEventDisableTiming | cudaEventInterprocess));
checkCudaErrors(cudaIpcGetEventHandle((cudaIpcEventHandle_t *)&shm->eventHandle[i], event));
ptrs.push_back(ptr);
events.push_back(event);
}
}
// Clean up!
for (i = 0; i < shm->nprocesses; i++) {
checkCudaErrors(cudaSetDevice(shm->devices[i]));
checkCudaErrors(cudaEventSynchronize(events[i]));
checkCudaErrors(cudaEventDestroy(events[i]));
checkCudaErrors(cudaFree(ptrs[i]));
}
// Launch the child processes!
for (i = 0; i < shm->nprocesses; i++) {
char devIdx[12]; // Increased size to ensure enough space for formatted integer
char *const args[] = {app, devIdx, NULL};
Process process;
sharedMemoryClose(&info);
snprintf(devIdx, sizeof(devIdx), "%d", i);
if (spawnProcess(&process, app, args)) {
printf("Failed to create process\n");
exit(EXIT_FAILURE);
}
processes.push_back(process);
}
// And wait for them to finish
for (i = 0; i < processes.size(); i++) {
if (waitProcess(&processes[i]) != EXIT_SUCCESS) {
printf("Process %d failed!\n", i);
exit(EXIT_FAILURE);
}
}
// Clean up!
for (i = 0; i < shm->nprocesses; i++) {
checkCudaErrors(cudaSetDevice(shm->devices[i]));
checkCudaErrors(cudaEventSynchronize(events[i]));
checkCudaErrors(cudaEventDestroy(events[i]));
checkCudaErrors(cudaFree(ptrs[i]));
}
sharedMemoryClose(&info);
}
int main(int argc, char **argv) {
int main(int argc, char **argv)
{
#if defined(__arm__) || defined(__aarch64__)
printf("Not supported on ARM\n");
return EXIT_WAIVED;
printf("Not supported on ARM\n");
return EXIT_WAIVED;
#else
if (argc == 1) {
parentProcess(argv[0]);
} else {
childProcess(atoi(argv[1]));
}
return EXIT_SUCCESS;
if (argc == 1) {
parentProcess(argv[0]);
}
else {
childProcess(atoi(argv[1]));
}
return EXIT_SUCCESS;
#endif
}