Converting space shared resources into intermittent resources for use in bag-of-tasks grids

Grid computing is turning from promise into reality. Naturally, however, this is not happening for all applications at once. Bag-of-tasks (BoT) applications (those parallel applications whose tasks are independent) are, due to their simplicity, the first class of applications to be massively executed on grids (e.g. SETI@home). BoT applications are especially amendable for grid execution because they can run on intermittent resources (i.e. resources with no guarantees on availability or reliability). In this scenario, good performance and reliable results are provided by eager schedulers, which rely on replication to overcome unfortunate task-to-processor assignments. A little surprisingly, however, eager schedulers are not prepared to use space-shared resources (e.g. parallel supercomputers). This happens because using a space-shared resource involves submitting a detailed request to the resource scheduler, specifying the number of processors needed and the amount of time these processors are to be allocated - information that eager schedulers are not prepared to provide. This is unfortunate because space-shared computers are the most powerful computing resources available today and thus could greatly improve the execution time of BoT applications. This work proposes an automatic way to craft such requests in order to convert space-shared resources into intermittent ones, therefore rendering them naturally usable by eager schedulers. Such conversion is based on adaptive heuristics and allows eager schedulers use such powerful computing resources without modifications.