INCORPORATING JOB SIZES IN DISTRIBUTED LOAD BALANCING

The load index most frequently used for load balancing in distributed systems is the job queue length. This work examines some of the implic ations of scheduling jobs according to an additional abstract dimensio n attribute called job size. The load balancing algorithm is supported by a virtual ring structure which organises the network nodes in grou ps and defines the information-gathering activities to take place with in and between such groups. A two-phase approach to information gather ing and decision making is adopted. This enables the selection of jobs for transfer to be delayed until as close as possible to the moment o f transfer. The operation of the protocol is described for each phase and synchronisation of the parallel activities in the virtual rings is discussed. The schedule length performance of the distributed algorit hm is examined in a series of closed-system tests.