As a sharing ecosystem, the Open Science Grid (OSG) doesn’t ‘own’ any computing resources. Open Science Grid consortium members connect their resources to perform computations for their own experiments, and to make available unused resources for other OSG members’ experiments. The shared compute cycles are called opportunistic.
These opportunistic cycles are helping US researchers accomplish science. The OSG plays a role, to be sure, but the virtual organizations (VOs) that own the sites with computing resources are key to this sharing success. Researchers are enabling other researchers. This sharing culture enables science in new ways. The sites that provide opportunistic access are the unsung heroes in this success, and they deserve a big thank you for sharing around 80 million computing hours to enable US research.
In July 2013, Dr. Meenakshi Narain—principal investigator of Brown University’s experimental particle physics group (which played a prominent role in the Higgs boson discovery) and coordinator of the Fermilab LHC Physics Center (LPC)—gave a glimpse into the roles of the OSG and the group. “The OSG brings the community together in a seamless way and helps us forge collaborations,” she said. Instead of duplicating each other’s work, researchers can compare data and models and share common tools. These collaborative efforts will help influence the design of future detectors at hadron colliders. Without the OSG’s culture of sharing, the Snowmass group’s critical role in the discovery of the Higgs boson might not have been possible.
This sharing culture enables peak management among the VOs. Anything not in use is made available to other researchers in the US. In total about 80 million hours of opportunistic cycles became available in 2013. One VO that benefited the most from these opportunistic resources is the OSG VO. It doesn’t own any computing resources and was created with one purpose in mind: Scavenging what is currently unused in the OSG ecosystem, and making it available for other US researchers to get work done. But this sharing is really a team sport in OSG. Other regional teams such as GLOW, Engage, HCC, and other VOs are enabling a broad set of US researchers. Across the OSG, over 50 researchers were supported in 2013 and this continues to grow.
Researchers can get complex scientific computation done in a much shorter timeframe because of the large pool of resources that the OSG makes available. The University of Wisconsin–Madison’s de Pablo Research Group, for example, captures the details of how DNA molecules interact with histone proteins using OSG compute power. They can run in excess of 3,000 simulations simultaneously, something they cannot do in their lab. They can also break very long simulations into trivially parallel simulations that don’t need to communicate with each other. As a result, their productivity has skyrocketed.
Opportunistic hours on the OSG in the last year amounted to more than 80 million, or about 1.5 million per week. If buying CPU time costs 5 cents per hour, that’s about $4 million. Aside from the monetary value, this sharing makes it possible for researchers to get their work done on compressed intervals that would be impossible without access to such a resource. The only ‘cost’ for researchers is acknowledging and citing the OSG, which is supported by the US National Science Foundation and the US Department of Energy’s Office of Science.
In a grid with over 100 sites, there is a good chance that—at any point in time—some sites will have unused capacity. The challenge is detecting availability in a timely fashion and matching it with the needs of researchers. OSG is currently working to improve their ability to identify and harvest these opportunistic resources. They are also increasing their efforts to reach out to US campuses to identify more researchers who can benefit from access to distributed high-throughput computing resources.