InfiniTensor/test/cuda/test_nccl_comm.cc

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#ifdef INFINI_USE_NCCL
#include "cuda/cuda_runtime.h"
#include "cuda/nccl_communicator.h"
#include "test.h"
static int WORLD_SIZE = 2;
namespace infini {
void allReduceSum(float *data, int deviceId) {
// Create Runtime and setup communication
CudaRuntimeObj *cuda_runtime = new CudaRuntimeObj(deviceId);
int rank = deviceId;
cuda_runtime->initComm("test_nccl_comm", WORLD_SIZE, rank);
ncclComm_t comm =
dynamic_cast<NcclCommunicatorObj &>(cuda_runtime->getCommunicator())
.getNcclComm();
// Copy data
float *data_gpu;
checkCudaError(cudaMalloc(&data_gpu, sizeof(float)));
checkCudaError(
cudaMemcpy(data_gpu, data, sizeof(float), cudaMemcpyHostToDevice));
// Do AllReduce
checkNcclError(
ncclAllReduce(data_gpu, data_gpu, 1, ncclFloat, ncclSum, comm, 0));
// Copy data back and sync device
checkCudaError(
cudaMemcpy(data, data_gpu, sizeof(float), cudaMemcpyDeviceToHost));
checkCudaError(cudaDeviceSynchronize());
}
// Setup communication between 2 threads, each controlling 1 GPU.
// Do AllReduce Sum on {1.0, 4.0}. Results should be {5.0, 5.0}.
TEST(NCCL, multi_gpu_communication) {
int num_threads = WORLD_SIZE;
float data[] = {1.0, 4.0};
std::vector<std::thread> threads;
for (int gpu = 0; gpu < num_threads; ++gpu) {
threads.emplace_back(allReduceSum, &data[gpu], gpu);
}
for (auto &thread : threads) {
thread.join();
}
for (int i = 0; i < num_threads; ++i) {
ASSERT_EQ(data[i], 5.0f);
}
}
} // namespace infini
#endif