Characterizing MPI and Hybrid MPI+Threads Applications at Scale: Case Study with BFS - Amer, Abdelhalim; Lu, Huiwei; Balaji, Pavan; Matsuoka, Satoshi (2015 15th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing, Cluster, Cloud and Grid Computing (CCGrid), 2015 15th IEEE/ACM International Symposium on, 2015)