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A Minimum Overhead CPU Utilization Measuring Algorithm

IP.com Disclosure Number: IPCOM000037674D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lamana, MA: AUTHOR

Abstract

A minimum overhead CPU utilization measuring algorithm is disclosed for efficiently measuring how much processor time is spent doing work in an operating software system. In a multiprocessing network, the operating system makes use of an executive service routine which decides if there is any work to be done by particular processors in the network. If there is, the executive dispatch is the appropriate routine or falls back to an idle routine which is part of the executive. The executive uses the time spent in the idle routine as a measure of the CPU utilization for a processor.

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A Minimum Overhead CPU Utilization Measuring Algorithm

A minimum overhead CPU utilization measuring algorithm is disclosed for efficiently measuring how much processor time is spent doing work in an operating software system. In a multiprocessing network, the operating system makes use of an executive service routine which decides if there is any work to be done by particular processors in the network. If there is, the executive dispatch is the appropriate routine or falls back to an idle routine which is part of the executive. The executive uses the time spent in the idle routine as a measure of the CPU utilization for a processor.

The CPU measurement algorithm allows the idle routine to idle away fixed amounts of CPU time before going back to look for more work. As is shown in the figure, a count is kept of the number of idle loops executed and when the count represents a predetermined value N, the processor time-of-day clock is recorded in a table. In this manner, for every time encountered in the table, N units of time were idled away. If a time between two entries is T then the CPU utilization is given by: % = (T-N)/T x 100.

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Disclosed anonymously.

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