Apparatus and method for conducting load balance to multi-processor system

Abstract

A method, system and apparatus for integrating a system task scheduler with a workload manager are provided. The scheduler is used to assign default priorities to threads and to place the threads into run queues and the workload manager is used to implement policies set by a system administrator. One of the policies may be to have different classes of threads get different percentages of a system's CPU time. This policy can be reliably achieved if threads from a plurality of classes are spread as uniformly as possible among the run queues. To do so, the threads are organized in classes. Each class is associated with a priority as per a use-policy. This priority is used to modify the scheduling priority assigned to each thread in the class as well as to determine in which band or range of priority the threads fall. Then periodically, it is determined whether the number of threads in a band in a run queue exceeds the number of threads in the band in another run queue by more than a pre-determined number. If so, the system is deemed to be load-imbalanced. If not, the system is load-balanced by moving one thread in the band from the run queue with the greater number of threads to the run queue with the lower number of threads.

Description

technical field [0001] The present invention is directed to resource allocation in computer systems. More specifically, the present invention is directed to methods and apparatus for load balancing the resources of a computer system based on certain limits or usage policies set by a system administrator. Background technique [0002] At any given processing time, there may be multiple user processes or threads waiting to execute on a processor or CPU of a computer system. In order to make the best use of the system's CPU, it is necessary to employ an efficient mechanism for properly queuing processes or threads waiting to execute. To accomplish this task, the mechanism adopted by most computer systems is to use a scheduler to complete the task. [0003] Note that a process is a program. When a program executes, it is loosely called a task. In most operating systems, there is a one-to-one relationship between tasks and programs. However, some operating systems allow a pr...

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Problems solved by technology

[0007] However, the problem is that sometimes in a two-processor system with, for example, two classes of processes (each with a different allocation number), it ends up that one processor handles one class of processes in its queue, while the other processor process another class of processes in its queue

When this occurs, the computer system's two processors may not be utilized as efficiently as the system administrator would like

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