gmres_aux.cu

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/*
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#include <stdio.h>
#include "gmres_kernel.h"
#include <device/device_config.h>
#include <device/cuda/check.h>
#include <device/cuda/buffer.h>
 
#ifdef HAVE_NVSHMEM
#include <nvshmem.h>
#include <nvshmemx.h>
#endif
 
extern "C" {
 
#include <math/bcknd/device/device_mpi_reduce.h>
#include <math/bcknd/device/device_mpi_op.h>
 
#ifdef HAVE_NCCL
#include <math/bcknd/device/device_nccl_reduce.h>
#include <math/bcknd/device/device_nccl_op.h>
#endif
 
  cuda_buffer_t gmres_redbuf = CUDA_BUFFER_INIT_SYMM;
 
  real cuda_gmres_part2(void *w, void *v, void *h, void * mult, int *j, int *n) {
 
    const dim3 nthrds(1024, 1, 1);
    const dim3 nblcks(((*n)+1024 - 1)/ 1024, 1, 1);
    const int nb = ((*n) + 1024 - 1)/ 1024;
    const cudaStream_t stream = (cudaStream_t) glb_cmd_queue;
 
    cuda_buffer_reserve(&gmres_redbuf, nb*sizeof(real));
    real *gmres_bf1 = (real *) gmres_redbuf.host;
    real *gmres_bfd1 = (real *) gmres_redbuf.dev;
 
    gmres_part2_kernel<real>
      <<<nblcks, nthrds, 0, stream>>>((real *) w, (real **) v,
                                      (real *) mult,(real *) h,
                                      (real *) gmres_bfd1, *j, *n);
    CUDA_CHECK(cudaGetLastError());
    reduce_kernel<real><<<1, 1024, 0, stream>>>((real *) gmres_bfd1, nb);
    CUDA_CHECK(cudaGetLastError());
 
#ifdef HAVE_NCCL
    device_nccl_allreduce(gmres_bfd1, gmres_bfd1, 1, sizeof(real),
                          DEVICE_NCCL_SUM, stream);
    CUDA_CHECK(cudaMemcpyAsync(gmres_bf1, gmres_bfd1, sizeof(real),
                               cudaMemcpyDeviceToHost, stream));
    cudaStreamSynchronize(stream);
#elif HAVE_NVSHMEM
    if (sizeof(real) == sizeof(float)) {
      nvshmemx_float_sum_reduce_on_stream(NVSHMEM_TEAM_WORLD,
                                           (float *) gmres_bfd1,
                                           (float *) gmres_bfd1, 1, stream);
    }
    else if (sizeof(real) == sizeof(double)) {
      nvshmemx_double_sum_reduce_on_stream(NVSHMEM_TEAM_WORLD,
                                           (double *) gmres_bfd1,
                                           (double *) gmres_bfd1, 1, stream);
    }
    CUDA_CHECK(cudaMemcpyAsync(gmres_bf1, gmres_bfd1, sizeof(real),
                               cudaMemcpyDeviceToHost, stream));
    cudaStreamSynchronize(stream);
#elif HAVE_DEVICE_MPI
    cudaStreamSynchronize(stream);
    device_mpi_allreduce(gmres_bfd1, gmres_bf1, 1, sizeof(real), DEVICE_MPI_SUM);
#else
 
    CUDA_CHECK(cudaMemcpyAsync(gmres_bf1, gmres_bfd1, sizeof(real),
                               cudaMemcpyDeviceToHost, stream));
    cudaStreamSynchronize(stream);
#endif
    return gmres_bf1[0];
  }
}