The svmon command

The svmon command provides a more in-depth analysis of memory usage. It is more informative, but also more intrusive, than the vmstat and ps commands. The svmon command captures a snapshot of the current state of memory. However, it is not a true snapshot because it runs at the user level with interrupts enabled.

# lslpp -lI bos.perf.tools

The svmon command can only be executed by the root user.

If an interval is used, which is the -i option, statistics will be displayed until the command is killed or until the number of intervals, which can be specified right after the interval, is reached.

You can use the following different reports to analyze the displayed information:

Global (-G)

Displays statistics describing the real memory and paging space in use for the whole system.

Process (-P)

Displays memory usage for the specified active processes. If no list of processes is supplied, the memory usage statistics display all active processes.

Segment (-S)

Displays memory usage for the specified segments. If no list of segments is supplied, memory usage statistics display all defined segments.

Detailed Segment (-D)

Displays detailed information on specified segments.

User (-U)

Displays memory usage statistics for the specified login names. If no list of login names is supplied, memory usage statistics display all defined login names.

Command (-C)

Displays memory usage statistics for the processes specified by command name.

Workload Management Class (-W)

Displays memory usage statistics for the specified workload management classes. If no classes are supplied, memory usage statistics display all defined classes.

Frame (-F)

Displays information about frames. When no frame number is specified, the percentage of used memory is reported. The only frames that are taken into account are the ones where the reference bit is set. During the processing period, all reference bits are reset. So, when the -f option is used a second time, the svmon command reports the percentage of real memory that has been accessed since the previous time the -f option was used. If a reserved pool is defined on the system, the percentage of memory used in each defined pool is reported.

Tier (-T)

Displays information about tiers, such as the tier number, the superclass name when the -a flag is used, and the total number of pages in real memory from segments belonging to the tier.