how to use 100% cpu for running parallel codes
I am using open mpi to run a parallel code. I am using an 8 core AMD processor. The code that i have made has a limitation that it can be run only on odd no. of processors. So when i run the code on 7 processors, all the cores show 100% usage (i.e. total cpu usage=87.5%). But when i run 2 codes using 5 and 3 cores respectively, the performance falls to 50% of 6 of the cores i.e. (total cpu usage =63.5%). Can someone suggest how to improve the performance of the cores?