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>
 
extern "C" {
 
#include <math/bcknd/device/device_mpi_reduce.h>
#include <math/bcknd/device/device_mpi_op.h>
  
  real * gmres_bf1 = NULL;
  real * gmres_bfd1 = NULL;
  int gmres_bf_len = 0;
 
  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;
    
    if (gmres_bf1 != NULL && gmres_bf_len < nb) {
      CUDA_CHECK(cudaFreeHost(gmres_bf1));
      CUDA_CHECK(cudaFree(gmres_bfd1));
      gmres_bf1 = NULL;
    }
 
    if (gmres_bf1 == NULL){
      CUDA_CHECK(cudaMallocHost(&gmres_bf1, nb*sizeof(real)));
      CUDA_CHECK(cudaMalloc(&gmres_bfd1, nb*sizeof(real)));
      gmres_bf_len = nb;
    }
     
    gmres_part2_kernel<real>
      <<<nblcks, nthrds, 0, stream>>>((real *) w, (real **) v,
                                      (real *) mult,(real *) h,
                                      gmres_bfd1, *j, *n);
    CUDA_CHECK(cudaGetLastError());
    reduce_kernel<real><<<1, 1024, 0, stream>>>(gmres_bfd1, nb);
    CUDA_CHECK(cudaGetLastError());
 
#ifdef 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];
  }
}