Processor Allocation Policies for Message-Passing Parallel Computers

When multiple jobs compete for processing resources on a parallel computer, the operating system kernel's processor allocation policy determines how many and which processors to allocate to each. In this paper we investigate the issues involved in constructing a processor allocation policy for large scale, message-passing parallel computers supporting a scientific workload. We make four specific contributions: ffl We define the concept of efficiency preservation as a characteristic of processor allocation policies . Efficiency preservation is the degree to which the decisions of the processor allocator degrade the processor efficiencies experienced by individual applications relative to their efficiencies when run alone. ffl We identify the interplay between the kernel processor allocation policy and the application load distribution policy as a determinant of efficiency preservation. ffl We specify the details of two families of processor allocation policies, called Equipartition a..