Walfredo Cirne is with Google's infrastructure group in California, USA. He is on leave of his faculty position at the Universidade Federal de Campina Grande, in Brazil. Dr. Cirne holds a Ph.D. from the University of California San Diego. Since 1997, he researches Grids and Resource Management, having led the OurGrid project from 2001 to 2006.

In order to submit a job for execution in most parallel supercomputers, one has to specify the number of processors to be allocated to the job. However, most parallel jobs in production today are moldable, i.e. it can run on a variety of number of processors, although such a number has to be fixed before the job starts. Consequently, users have to decide how many processors to request whenever they submit a moldable job. We here show that the request that submits a moldable job can be automatically selected in a way that often reduces the job s turn-around time. More precisely, we will introduce and evaluate SA, an application scheduler that chooses which request to use to submit a moldable job on behalf of the user. The user provides SA with a set of possible requests that can be used to submit a given moldable job. SA estimates the turn-around time of each request based on the current state of the supercomputer, and then forwards to the supercomputer the request with the smallest expected turn-around time.