One-sided Communication

• Basic idea:
  task can directly access memory of other tasks (similar to shared memory model)
  owner of a memory area must allow access
  several synchronisation methods available
• Application areas:
  irregularly distributed data (f.i. sparse matrices)
  dynamical load balancing with strongly varying task sizes (e.g. in computational chemistry)
• Important functions:
  MPI_Alloc_mem

  • allocation of suitable memory
  MPI_Win_create, MPI_Win_free

  • creates/destroys a window = memory area which can be accessed by tasks of the same group
  MPI_Get, MPI_Put, MPI_Accumulate

  • remote memory access: read, write, sum/multiply etc.
  MPI_Win_lock, MPI_Win_unlock

  • access synchronisation with locking mechanism (mutual exclusion)
  MPI_Win_fence

  • synchronisation by access "barrier"
• Example program