I got this from Prof. Toyotaro Suzumura from the Tokyo Institute of Technology. ScaleGraph is a graph processing system written using X10 distributed programming language. ScaleGraph is open source software using Eclipse License.
From their website: "Recently large-scale graphs with billions of vertices and edges have emerged in a variety of domains and disciplines especially in the forms of social networks, web link graphs, internet topology graphs, etc. Mining these graphs to discover hidden knowledge requires particular middleware and software libraries that can harness the full potential of large-scale computing infrastructures such as super computers.
ScaleGraph is a graph library based on the highly productive X10 programming language. The goal of ScaleGraph is to provide large-scale graph analysis algorithms and efficient distributed computing framework for graph analysts and for algorithm developers, respectively."
I have invited ScaleGraph to present at our 3rd GraphLab conference.