Browse Prior Art Database

Monitor Of System Events

IP.com Disclosure Number: IPCOM000048513D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Herrington, KM: AUTHOR [+3]

Abstract

In large systems, especially systems that provide a multi-task environment, it is necessary to be able to understand the relationship and interaction between the various processes. It is necessary to be able to determine the path length of specific sequences of instructions and the frequency of execution of those sequences. It is also necessary to record the history of those events to aid in problem determination in order to see the events that led to the programming error or the like. However, due to the critical performance requirement, the overhead associated with recording these events may be unacceptable in the final product.

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Monitor Of System Events

In large systems, especially systems that provide a multi-task environment, it is necessary to be able to understand the relationship and interaction between the various processes. It is necessary to be able to determine the path length of specific sequences of instructions and the frequency of execution of those sequences. It is also necessary to record the history of those events to aid in problem determination in order to see the events that led to the programming error or the like. However, due to the critical performance requirement, the overhead associated with recording these events may be unacceptable in the final product.

The system monitor is a software tool designed to record significant system events (or user-defined events). When an event occurs, the system monitor gathers pertinent information associated with that event and records that data either in an internal trace table or outputs that data to an externally connected hardware monitor or both. The information output to the hardware monitor is processed by data reduction programs to provide timing information for performance measurement.

The system monitor gains control at selected system interrupts or at user- defined code points. After the data associated with the event has been recorded, the system monitor returns control to the program in such a way that the system monitor processing is transparent to the application being monitored. An event is associated with a system interrupt, there being 8 hardware events, 25 events associated with service routines, and 8 events associated with supervisory routines. During initial system loading, a determination is made whether the system monitor is to be activated or not. If the system monitor is to be activated, then the interrupt vectors for the...