SOS CPU Summary

The CPU Summary Screen

The CPU Summary screen reports the general state of one or more CPUs in graphical and tabular formats.

To access the CPU Summary screen from any SOS display screen:

Type s from the SOS Enter command: prompt to view the Screen Selection Menu screen.

From the Screen Selection Menu screen, enter c (CPU Summary). The CPU Summary screen will display.

Type t to toggle between the graphical and tabular displays.

Examples of the CPU Summary screen are provided in "Graphical Format" (next page) and "Tabular Format".

CPU Summary Display Items

Graphical Format

The graphical CPU Summary screen contains a horizontal bar graph of the CPU utilization statistics for each CPU on the system. Figure 10.1 shows an example of the screen.

Figure 10.1 SOS CPU Summary screen (graphical format)

CPU SUMMARY

Each CPU SUMMARY data item is described in the next table.

Table 10.1 SOS CPU SUMMARY (graphical format) data items

Data Item	Description
CPU	The CPU column contains the sequential identification numbers assigned to the individual CPUs by SOS. For example, if the system uses four processors, the graphical CPU summary would include four lines in the bar graph, and these lines would be numbered 1 through 4 in the CPU column.
Utilization%	The Utilization% values provided in the CPU SUMMARY bar graph represent the percentage of CPU time expended during the current measurement interval on various activities. The CPU Utilization% data in the CPU Summary screen is reported exactly like the CPU% data in the Global Summary screen. For a description of each possible CPU activity, refer to "CPU%".
Busy%	The Busy% value shown on the right portion of the CPU SUMMARY represents the total percentage of time the CPU was busy (not idle) during the current (nnn.n) and elapsed ([nnn]) intervals (if applicable).
Total	The Total value represents the average utilization percentage of all CPUs during the current interval.

Tabular Format

The tabular CPU Summary screen contains CPU utilization information organized into four categories:

Total CPU utilization statistics (CPU SUMMARY).

CPU Run queue statistics (RUNQ STATISTICS).

Miscellaneous CPU statistics (MISC STATISTICS).

CPU utilization statistics for each CPU on the system (PER CPU UTILIZATION).

Figure 10.2 shows an example of the CPU Summary screen in tabular format.

Figure 10.2 SOS CPU Summary screen (tabular format)

CPU SUMMARY

The CPU SUMMARY portion of the tabular CPU Summary screen displays the average percentage of CPU time expended on various activities during the current interval. Cumulative averages for the elapsed interval can also be displayed. For instructions, refer to "Display cumulative stats". Each data item is described in the following table.

Table 10.2 SOS CPU SUMMARY (tabular format) data items

Data Item	Description
BUSY	The total percentage of time the CPU was busy.
USER	The percentage of time the CPU spent executing user program code with a nice value of 20 and without any special priority.
SYS	The percentage of time the CPU spent executing system calls and code (in kernel mode). This value does not include time spent performing context switches or idle time.
WAIT	The percentage of idle time the CPU was waiting for a disk I/O to complete.
IDLE	The percentage of time the CPU was not in use.

RUNQ STATISTICS

The RUNQ STATISTICS portion of the tabular CPU Summary screen contains the CPU run queue statistics for the current interval (and the elapsed interval if cumulative statistics are shown). Each data item is described in the following table.

Table 10.3 SOS RUNQ STATISTICS data items

Data Item	Description
Internal Avg	The average number of processes in the run queue.
1/5/15 Min Avg	The average number of processes in the run queue during the current 1-, 5-, and 15-minute periods, respectively.
Occ %	The percentage of time there was one or more processes in the run queue.

MISC STATISTICS

The MISC STATISTICS portion of the tabular CPU Summary screen provides some miscellaneous CPU statistics for the current and /or elapsed interval(s). Each data item is described in the next table.

Table 10.4 SOS MISC STATISTICS data items

Data Item	Description
Forks	The number of forks per second.
Smtx	The number of CPU mutual exclusion locks per second. 4 Performance Tip CPU mutual exclusion locks are used to limit access to certain kernel structures to one CPU at a time. An excessive rate could indicate the need for faster CPUs. More CPUs will make the problem worse.
C Sws	The number of context switches per second that occurred in the interval.
Intrs	The number of interrupts per second.
Traps	The number of traps per second.
Sys C	The number of system calls per second.

PER CPU UTILIZATION

The PER CPU UTILIZATION portion of the tabular CPU Summary screen displays the same data listed in the CPU SUMMARY portion of the screen for each CPU on the system. Please refer to "CPU SUMMARY" for a description of each data item.