What is a service unit (SU)?

Time on TeraGrid resources is allocated in service units, or SUs, which are the basic units of TeraGrid accounting. SUs are used to make fair comparisons and allocations of resources of different types, speeds, and capacities. A TeraGrid SU originally represented one CPU-hour on the IA-64 clusters that were available during phase I of the Distributed TeraScale Facility (DTF). SUs on other computational systems are calculated using a normalization factor based on benchmark results relative to the phase I DTF cluster.

Since the TeraGrid has expanded to provide a variety of resources in addition to computing cycles, not all TeraGrid allocations are requested in SUs. For example, requests for storage are now made directly in terabytes, rather than converted to SUs. Based on estimates of the cost to provide resources and services, non-computational resources are also categorized into developmental, medium, and large requests, which are reviewed by different committees.

This document was developed with support from the National Science Foundation (NSF) under Grant No. 0503697 to the University of Chicago and subcontracted to Indiana University. Additional support was provided by IU through its participation in the TeraGrid, which is supported by the NSF under Grants No. 0833618, SCI451237, SCI535258, and SCI504075. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.

Also see:

• How do I apply for a new TeraGrid allocation?
• On the TeraGrid, how do I convert service units on one platform to the equivalent amount on another platform?