add device memory MPI_Put

one_sided_gpu.cpp

@@ -0,0 +1,61 @@
+#include <mpi.h>
+#include <cuda_runtime.h>
+#include <iostream>
+
+inline void checkCuda(cudaError_t result, const char *file, const int line) {
+  if (result != cudaSuccess) {
+    fprintf(stderr, "%s:%d: CUDA Runtime Error %d: %s\n", file, line, int(result), cudaGetErrorString(result));
+    exit(-1);
+  }
+}
+#define CUDA_RUNTIME(stmt) checkCuda(stmt, __FILE__, __LINE__);
+
+int main(int argc, char **argv) {
+
+  MPI_Init(&argc, &argv);
+
+  int *a{};
+  MPI_Win win;
+  {
+    MPI_Aint size = sizeof(int);
+    int disp_unit = sizeof(int);
+    CUDA_RUNTIME(cudaMalloc(&a, size));
+    MPI_Win_create(a, size, disp_unit, MPI_INFO_NULL, MPI_COMM_WORLD, &win);
+  }
+
+  int rank, size;
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+  MPI_Comm_size(MPI_COMM_WORLD, &size);
+
+  // expect our a to be set by the left
+  int source;
+  if (0 == rank) {
+    source = size - 1;
+  } else {
+    source = rank - 1;
+  }
+
+  int target; // set the right
+  if (rank == size - 1) {
+    target = 0;
+  } else {
+    target = rank + 1;
+  }
+
+  // start exposure of window
+  MPI_Win_fence(0, win);
+
+  // send our rank to the target window
+  std::cout << "rank " << rank << " put to " << target << std::endl << std::flush;
+  MPI_Put(&rank, 1, MPI_INT, target, 0, 1, MPI_INT, win);   
+
+  // end exposure of window
+  MPI_Win_fence(0, win);
+
+  int err = 0;          
+
+  MPI_Win_free(&win);
+  MPI_Finalize();
+  std::cout << "rank " << rank << " completed" << std::endl << std::flush;
+  return err;
+}