Browse Prior Art Database

Load Level Scheduler

IP.com Disclosure Number: IPCOM000120645D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 4 page(s) / 115K

Publishing Venue

IBM

Related People

Brown, CL: AUTHOR [+2]

Abstract

This article discloses a function that can control system resources (CPU, storage, paging and I/O) for batch processing automatically, rather than the manual controls currently provided. This program allows each installation the ability to define and measure performance and suspend/resume jobs based on system performance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Load Level Scheduler

      This article discloses a function that can control system
resources (CPU, storage, paging and I/O) for batch processing
automatically, rather than the manual controls currently provided.
This program allows each installation the ability to define and
measure performance and suspend/resume jobs based on system
performance.

      System contention is measured by keeping a running average of
the length of the CP Queues, as measured by the CP INDICATE QUEUES
command -*-.  Measurements are taken every three seconds, and the
average over the last five measurements constitutes a "Measured
Contention Value" (MCV) (see Fig. 1).  An MCV is maintained for each
of the following four resources:
     MCV-CPU reflects the averaged count of users in CPU wait (status
QN - from IND Q)
     MCV-PG reflects the averaged count of users in Page wait (status
QN PG from IND Q)
     MCV-IO reflects the averaged count of users in IO wait (status
QN IO from IND Q)
     MCV-ST reflects the averaged count of users in Storage wait
(status En from IND Q,n = 1 to 3)

      Each site can initially define, and dynamically modify, system
contention values for each of the four resources:
    the Suspend Contention Value (SCV); such that when the MCV
exceeds the SCV for the resource, the LLS acts to decrease the batch
workload in the area of that resource.
     the Resume Contention Value (RCV); such that when the MCV falls
below the RCV for the resource, the LLS acts to restore the batch
workload in the area of that resource
     The Resume Contention Decrement (RCD); such that if a thrashing
of LLS suspend/resume activity for a resource occurs, the LLS will
automatically decrement the RCV by the RCD for the resource, to
prevent further thrashing.

      When a job is submitted for batch processing, it is defined to
be either subject to Load Level Scheduler (LLS) control or
independent of it.  Job subjection to LLS is defined by class and may
be overridden by individual jobs.

      When a new job subject to LLS is selected for dispatch and
contention for any resource exists or resolution is required, the job
is not dispatched; otherwise, the job is dispatched (see Fig. 2).  In
this way, the lo...