Method for load balancing a per processor affinity scheduler wherein processes are strictly affinitized to processors and the migration of a process from an affinitized processor to another available processor is limited

摘要

An improved affinity process scheduling method for a multiprocessor computer system, wherein a process previously executed on a processor within the computer system is affined to the processor on which it previously executed, and will be scheduled for execution by the affined processor during subsequent requests for execution of the affined process. The improved affinity process scheduling method monitors the length of time the affined process resides on the system run queue awaiting execution by its affined processor; and schedules the affined process for execution with another available processor when the length of time the affined process has been waiting for execution exceeds a predetermined "steal-age" threshold. The improved affinity process scheduling method also monitors the processing load borne by the affined processor, determines therefrom a headroom parameter for the affined processor, the headroom parameter indicating the remaining load capacity of the affined processor; and schedules the affined process for execution with another available processor when the headroom of the affined processor is less than a predetermined "low-headroom" threshold.