US 4,145,735 AGranted

Monitor for priority level of task in information processing system

AssigneeNippon Steel Corporation

InventorHiromu Soga

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Abstract

The present invention is a monitor for the priority level of tasks in a computer in which priority levels are assigned to tasks in such a manner that a higher priority level is assigned with a shorter time. During the period when a task assigned with an optional priority level is processed, its processing time is measured and recorded by means of a level timer. In case a second task with a high priority level interrupts the first task and the processing is suspended, the measuring and recording of time are stopped, and the measured and recorded values are stored. When the processing of the second task is completed and the processing of the first task is started again, measuring and recording are started again from the stored values. When the processing time of the first task exceeds the processing time assigned to its priority level, the processing of the first task is suspended and a warning is issued.

Claims5

Dependent claims

In a data processing where a number of tasks share a central processing unit according to a plurality of priority levels, a priority level monitor comprising:

a control register coupled to said central processing unit for receiving from said central processing unit signals indicating the beginning of the execution of a task, the completion of the execution of that task and the priority level associated with that task and for storing said signals;
a priority level timer connected to said control register for measuring the execution time of each task processed by said central processing unit and for generating an overflow signal when the execution time of a task exceeds a predetermined permissible execution time allowed to tasks having the priority level of said task;
and
an interrupt signal generator connected to said priority level timer and said central processing unit for generating an interrupt signal and transmitting said interrupt signal to said central processing unit when said priority level timer generates said overflow signal, whereby said apparatus monitors the execution time of tasks assigned to each priority level and causes a task to be aborted when the execution time of the task exceeds a predetermined permissible execution time allowed to tasks of that priority level.

1 more element

Dependencies are inferred from the claim text.