SOS Memory Summary

The Memory Summary Screen

The Memory Summary screen provides a detailed look at memory and virtual memory performance.

Figure 11.1 SOS Memory Summary screen

To access the Memory 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 m (Memory Summary). The Memory Summary screen will display. Figure 11.1 shows an example of the screen.

Memory Summary Screen Display Items

MEM/VM ALLOCATION

The MEM/VM ALLOCATION portion of the Memory Summary screen shows how RAM and virtual memory are allocated on the system. The data items are described in the following table.

Table 11.1 SOS MEM/VM ALLOCATION data items

Data Item	Statistics	Description
Mem	Size	The amount of RAM (MB) installed on the system.
	Used	The amount of RAM (MB) used during the interval.
	Free	The amount of RAM (MB) free (unused) on the system.
VM	Size	The amount of virtual memory (MB) enabled on the system.
	Used	The amount of virtual memory (MB) used during the interval.
	Free	The amount of virtual memory (MB) free (unused) on the system.

PROC MEM STATUS

The PROC MEM STATUS portion of the Memory Summary screen shows where processes are currently located from a memory viewpoint. Each data item is described in the next table.

Table 11.2 SOS PROC MEM STATUS data items

Data Item	Description
Run	The number of swapped processes that are ready to run. In other words, the length of the CPU run queue.
Sleep	The number of processes that are sleeping.
Total	The total number of processes swapped during the interval.

PAGING

The PAGING portion of the Memory Summary screen displays detailed statistics on paging activity for the interval. Each data item is described in the following table.

Table 11.3 SOS PAGING data items

Data Item	Description
In (/s)	The number of swaps in per second.
Out (/s)	The number of swaps out per second.
In (byte/s)	The number of bytes swapped in per second.
Out (byte/s)	The number of bytes swapped out per second.
#In	The number of swaps in.
#Out	The number of swaps out.

PAGE SCANNER

The PAGE SCANNER portion of the Memory Summary screen displays data the page scanning process for the interval. Each data item is described in Table 11.4.

Table 11.4 SOS PAGE SCANNER data items

Data Item	Description
Page Recs	The number of pages reclaimed per second.
Page Scans	The number of pages scanned by the page scanner per second.
Ave Page Res	The average page residence time in milliseconds. The Ave Page Res value the average amount of time a page is able to stay in memory. The default value is 600, which means that pages are not being forced from memory. Lower numbers indicate that pages are being forced out of memory.

MEMORY MANAGEMENT CONFIG

The MEMORY MANAGEMENT CONFIG portion of the Memory Summary screen displays the values of key memory management variables. Each data item is described in the following table.

Table 11.5 SOS MEMORY MANAGEMENT CONFIG data items

Data Item	Description
lotsfree	The upper bound for paging. Once paging has started, it will continue until free memory (refer to "MEM/VM ALLOCATION") is larger than lotsfree.
desfree	The lower bound for paging. When free memory drops below desfree, paging begins.
minfree	The threshold at which the system considers itself to be out of memory. At this point, the system will start deactivating processes.
throttlefree	The threshold at which any process that attempts to get another page will be suspended until the amount of free memory exceeds desfree.
priority paging	The priority paging value is either 0 (zero) or 1. If 0, priority paging is not enabled. If 1, priority paging is enabled. Priority paging, when enabled, modifies the paging algorithm to page out data pages before text, heap, and stack.
maxpgio	The maximum number of page I/O operations per second that the system will schedule.
page size	The size of pages in bytes.
fastscan	The fastest scan rate in pages per second. This value corresponds to an empty free list.
slowscan	The initial scan rate in pages per second. The initial scan rate is measured when page scanning first starts.