checkgpus/bw.cpp at main · dylanjude/checkgpus · GitHub

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#include <cstdio>
#include <cstdlib>
#include <string>
#include "mpi.h"
#include "cuda_runtime.h"
#include "helper.h"

#define WIN_SIZE      64
#define DEVICE_BUFFER 1

//
// this code is mostly copied from osu_bw
//

void bwtest(int size0, int size1){

  int myid, numprocs, i, j;
  double t_start = 0.0, t_end = 0.0, t = 0.0;
  int size;
  int namelen;

  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
  MPI_Comm_rank(MPI_COMM_WORLD, &myid);

  char *s_buf;
  char *r_buf;

#ifdef DEVICE_BUFFER
  HANDLE_ERROR(cudaMalloc(&s_buf, size1));
  HANDLE_ERROR(cudaMalloc(&r_buf, size1));
#else
  s_buf = new char[size1];
  r_buf = new char[size1];
#endif

  MPI_Request request[WIN_SIZE];
  MPI_Status  reqstat[WIN_SIZE];

  if(numprocs < 2){
    return;
  }

  if(myid == 0){
    printf("\n ----- Checking bandwidth from rank 0 to all other ranks ------- \n\n");
  }

  // loop over the proc that will receive data
  for(int p=1; p<numprocs; p++){
    // loop over packet size
    for(size = size0; size<=size1; size*=4){

      if(myid == 0){

        t_start = MPI_Wtime();
        for(j = 0; j < WIN_SIZE; j++){
          MPI_Isend(s_buf, size, MPI_CHAR, p, 100, MPI_COMM_WORLD, request + j);
        }
        MPI_Waitall(WIN_SIZE, request, reqstat);
        MPI_Recv(r_buf, 4, MPI_CHAR, p, 101, MPI_COMM_WORLD,&reqstat[0]);

        t_end = MPI_Wtime();
        t = t_end - t_start;

      } else if(myid == p){
        for(j = 0; j < WIN_SIZE; j++) {
          MPI_Irecv(r_buf, size, MPI_CHAR, 0, 100, MPI_COMM_WORLD,request+j);
        }

        MPI_Waitall(WIN_SIZE, request, reqstat);
        MPI_Send(s_buf, 4, MPI_CHAR, 0, 101, MPI_COMM_WORLD);

      }

      if(myid == 0) {
        double tmp = size / 1e9 * WIN_SIZE;
        printf("N=%10d   |  0 -> %3d  |  %7.4f GB/s\n", size, p, tmp/t);
        fflush(stdout);
      }
    }
    if(myid==0){
      printf("----\n");
    }
  }

  if(myid == 0){
    printf("------------------------------------------\n");
  }

#ifdef DEVICE_BUFFER
  HANDLE_ERROR(cudaFree(s_buf));
  HANDLE_ERROR(cudaFree(r_buf));
#else
  delete[] s_buf;
  delete[] r_buf;
#endif

}