This thesis describes demand-based c oscheduling, a new approach t o s c heduling parallel computations on multiprogrammed multiprocessors. In demand-based coscheduling, rather than making the pessimistic assumption that all the processes constituting a parallel job must be simultaneously scheduled in order to achieve good performance, information about which processes are communicating is used in order to coschedule only these; the resulting scheme is well-suited to implementation on a w orkstation cluster because it is naturally decentralized. I present an analytical model and simulations of demand-based coscheduling, an implementation on a cluster of workstations connected by a high-speed network, and a set of experimental results. An analysis of the results shows that demand-based coscheduling successfully coschedules parallel processes in a timeshared workstation cluster, signi cantly reducing the response times of parallel computations.
AbstractThis thesis describes demand-based c oscheduling, a new approach t o s c heduling parallel computations on multiprogrammed multiprocessors. In demand-based coscheduling, rather than making the pessimistic assumption that all the processes constituting a parallel job must be simultaneously scheduled in order to achieve good performance, information about which processes are communicating is used in order to coschedule only these; the resulting scheme is well-suited to implementation on a w orkstation cluster because it is naturally decentralized. I present an analytical model and simulations of demand-based coscheduling, an implementation on a cluster of workstations connected by a high-speed network, and a set of experimental results. An analysis of the results shows that demand-based coscheduling successfully coschedules parallel processes in a timeshared workstation cluster, signi cantly reducing the response times of parallel computations. Acknowledgments 1Sometimes when looking through a thesis I nd that it contains a very long acknowledgments section, which more often than not proves upon examination to be a very personal document. When the writer is a friend, I enjoy reading the acknowledgments, especially if my name is mentioned. When the writer is someone I know only professionally, m y reaction is typically embarassment tinged with distaste. I am reminded of a Peanuts cartoon I read when I wa s a c hild, in which Snoopy s a w a dog riding in a car with its head out the window and its tongue apping in the breeze. Snoopy thought that if he were in a car he would never behave in so undigni ed a manner; rather, he would sit up straight and wear a seat belt. It will be clear, then, that in order to maintain a digni ed posture and spare the reader embarassment, I should like to write a brief and formal acknowledgments section, but when I look back on the work that has occupied me for most of three years, I realize that that I am so indebted to colleagues, family, and friends, that to do so would be out of the question. Thus to the reader who does not kno...