Parallelizing the MARS15 Code with MPI for Shielding Applications
  The MARS15 Monte Carlo code capabilities to deal with time-consuming deep penetration shielding problems and other computationally tough tasks in accelerator, detector and shielding applications, have been enhanced by a parallel processing option. It has been developed, implemented and tested on the Fermilab Accelerator Division Linux cluster and network of Sun workstations. The code uses MPI. It is scalable and demonstrates good performance. The general architecture of the code, specific uses of message passing, and effects of a scheduling on the performance and fault tolerance are described. 
M. A. Kostin and N. V. Mokhov