Gang scheduling for the IBM SP-2 workstation cluster

The IBM SP2 is a workstation cluster that executes IBM's version of standard UNIX (AIX) on each processor and provides interprocessor communication via MPI or IP using the SP2 high performance switch. The objective of the scheduling system for the SP2 cluster is to (a) overcome the single process per processor restriction without compromising performance, reliability or security as accustomed to in the dedicated mode, and (b) to provide a general framework to implement flexible scalable scheduling policies based on the principle of gang scheduling. The structure of the scheduler framework consists of three collaborating modules: (1) a global scheduler, (2) a local scheduler and (3) an interface to efficiently interact with the communication subsystem.