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Resource Preemption for Priority Scheduling

IP.com Disclosure Number: IPCOM000080267D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Edel, TR: AUTHOR [+2]

Abstract

Resource allocation is involved with granting resources to requestors on the basis of different algorithms, namely FIF0, priority, etc. When resources become available, they are allocated to the requestors according to the particular algorithm selected. This description extends this concept, by preempting held resources when a higher priority requestor issues a request for those resources. This can be used to honor requests for resources at a particular time, as well as to dynamically obtain resources based on the current execution environment.

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Resource Preemption for Priority Scheduling

Resource allocation is involved with granting resources to requestors on the basis of different algorithms, namely FIF0, priority, etc. When resources become available, they are allocated to the requestors according to the particular algorithm selected. This description extends this concept, by preempting held resources when a higher priority requestor issues a request for those resources. This can be used to honor requests for resources at a particular time, as well as to dynamically obtain resources based on the current execution environment.

This permits a higher degree of resource utilization and is in direct contrast to "reserving" a resource, in order to insure availability.

For example, a request for resource X may be made several hours in advance of its actual use. However, the system may continue to honor requests for resource X during that period, knowing that the system will fulfill its prior commitment by preemption.

Thus, if a request is made to run Job A at 3:00 P. M. requiring held resources, those resources would be preempted from their current owner, in order to be given to Job A, if Job A has a higher priority. In order to achieve this, an external criteria (i.e., priority) must be maintained on the basis of requesting user identification. Examples of preemptable resources are:

--CPU execution (note that this is currently available

on mainline system)

--I/O device

--Data.

Developed to its fullest exten...