This paper presents GRIDHPC, a decentralized environment dedicated to high performance computing. It relies on the reconfigurable multi network protocol RMNP to support data exchange between computing nodes on multi network systems with Ethernet, Infiniband, Myrinet, and on OpenMP for the exploitation of computing resources of multicore CPU. We report on scalability of several parallel iterative schemes of computation combined with GRIDHPC. In particular, the experimental results show that GRIDHPC scales up when combined with asynchronous iterative schemes of computation.