HP 3000 Manuals HP 3000 Manuals
Appendix A Multiprocessor Systems In addition to single-processor systems, MPE now supports multiprocessor systems--systems that have more than one processor (CPU) board. To determine if you have a multiprocessor system, examine the banner line of the GlancePlus Global screen. If more than one processor is configured, the total number of configured processors will be displayed in the area to the right of the word "Global." If this area is blank, your system has only one processor configured. The following is an overview of how GlancePlus presents CPU metrics on a multiprocessor system. Global CPU bars and their associated percentages are presented relative to all processors on the system. Any process CPU metric is presented relative to a single processor. For example, if a two- processor system has only one active process that constantly consumes CPU, then the Interesting Process section of the Global screen will show 100% CPU for that process. The Global CPU bar will display 50% (100% divided by the number of processors). If that same system had two processes constantly consuming the CPU, then each process would show 100% CPU and the Global CPU bar would display 100% (100% plus 100%, divided by the number of processors). Screens that represent groups of processes (the Job, Session, Filter, and Workload screens) present their data as follows: CPU bars and their associated percentages are displayed relative to all processors. CPU-seconds are displayed relative to a single processor. For example, a Job screen showing a job with one process constantly using the CPU would display the JOB CPU bar at 50% (just like the Global bar). The CPU total-seconds would increment at the same rate as clock time. The process in this display would still show CPU usage at 100% since it is displayed relative to a single processor. These choices of design for presenting CPU usage represent tradeoffs. It is useful to present process CPU usage relative to a single processor since other MPE sources such as the system log files, the REPORT command, the SHOWME command, and log-off statistics also present CPU usage relative to a single processor. It is advantageous to represent CPU-seconds on the Job, Session, and Filter screens relative to a single processor so they can be compared properly to other MPE sources. In addition, it is useful to scale the CPU bars between 0 and 100% of the total processing power of the system, or relative to all processors. By doing this, 100% means that the total CPU power of the system is utilized completely, regardless of the number of processors utilized. The tradeoff for these advantages is the need to be able to understand that it is reasonable for a two-processor system to have a Global CPU bar showing 100% usage and two processes in the interesting process section each using 100% (of a single processor). The user must understand the difference between Global CPU bar and individual process presentations. Once this is understood, the user need not consider the number of CPUs in use to easily understand how CPU-intensive each process is and how much total processing power is in use.