Introduction If you are installing a system program update tape, use this
publication in conjunction with the "emo to Users supplied on the PUT. If you wish to install the Remote Spooling Communications Subsystem (RSCS) do so after running the IVP. After you generate VM/370 (CP, CMS, IPCS, and, optionally, RSCS), you can generate the 3704/3705 Control
Program. Information about this program is found in Part 4 of this manual.
6 IBM VM/370 Planning and System Generation Guide

Performance Guidelines
Performance Guidelines The performance characteristics of an operating system when it is run in
a virtual machine environment are difficult to predict. This
unpredictability is a result of many factors: • The System/370 model used • The system environment used (uniprocessor or attached processor) • The total number of virtual machines executing • The type of work being done by each virtual machine • The speed, capacity, and number of the paging devices • The amount of real storage available • The degree of channel and control unit contention, as well as arm
contention, affecting the paging device • The type and number of VK/370 performance options in use by one or
more virtual machines • The availability of VM/370 hardware assist • The favored priority and V=R options in effect
Also, the virtual machine's channel mode, block multiplexer or selector,
has an effect on the virtual machine's performance. !Qig: The performance of an KSS being accessed by
and shared with other systems depends on the total
contention.
Performance Measurement and Analysis
the operating system KSS utilization and
The VK/370 control program has two commands that measure system
performance and, thus, help you identify problem areas. The MONITOR command collects system measurement data offline for the system operator
or system analyst, while the INDICATE command displays system
measurement data online for the system operator, system analyst or
gen eral user.
The MONITOR command controls the collection of performance data and
writing it to system spool files or tapes. Both summary and trace data
can be collected. The classes of data collected may be specified using
either the operands of the MONITOR command or those of the SYSMON macro
instruction. The classes selected depend on the nature of the analysis
to be performed. The IBM Field Developed Program (FOP) VM/370: Performance/"onitor Analysis Program can be used to reduce the data
collected. The guidelines for using this program provide the user with
information that will aid him in determining the overall load
environment and performance profile of his system. The VM/370 Performance/Monitor Analysis Program should enable him to analyze the
utilization of and contention for the major system resources such as the CPU, storage, and I/O paging subsystems. Part 1. Planning for System Generation 7