One of the biggest huddles faced by researchers studying algorithms for
massive graphs is the lack of large input graphs that are essential for the
development and test of the graph algorithms. This paper proposes two efficient
and highly scalable parallel graph generation algorithms that can produce
massive realistic graphs to address this issue. The algorithms, designed to
achieve high degree of parallelism by minimizing inter-processor
communications, are two of the fastest graph generators which are capable of
generating scale-free graphs with billions of vertices and edges.