SOS Memory Detail
The Memory Detail Screen is useful when you want to analyze memory activity from either a
tabular or graphic view point.
To access the Memory Detail Screen from the global 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 Detail Screen). The Memory Detail Screen will display.
These screens are designed to give you a specialized look at memory management activities.
You can look at these events via a graphic display or in a tabular format by pressing the
appropriate function key. The tabular format provides more detail along with cumulative numbers.
The graphic format is easier to observe over time.
Memory Detail Screen Keys
All of the Memory Detail Screen keys are identical with the keys of the CPU Detail Screen. See
"CPU Detail Screen Keys" for details.
Memory Detail Screen Display Items
The Memory Detail screen can be displayed in two formats. Examples of the Memory Detail
Screen are provided in
"Graphical Format" (next page) and
"Tabular Format".To toggle between a
Graphic and Tabular display format press the G key or press the F4 function key.
Graphical Format
Figure 15.1 shows an example of the Memory Detail screen in graphical format.
Figure 15.1 SOS Memory Detail screen (graphical format)
Memory Detail (graphical format)
Each character on the graphic bar represents approximately two events per second. All values
are expressed in number of events per second. The key to each graphic bar and tabular column is
shown in the next table.
Table 15.1 SOS Memory Detail screen keys
|
Key
|
Description
|
|
C
|
Native mode and compatibility mode code segments (NM code and CM code).
|
|
D
|
Transient and permanent data segments (Tran Data and Perm Data).
|
|
F
|
File object faults (all types: Image, KSAM, etc.).
|
|
L
|
Native mode and compatibility mode system libraries such as XL.PUB.SYS, SL.PUB.SYS, etc. (NM Sys and M Sys).
|
|
S
|
Native mode and compatibility mode data stacks (NM stack and CM stack).
|
|
X
|
Compatibility mode extra data segments (CM Xds).
|
The Memory Detail data items are described in the following table.
Table 15.2 SOS Memory Detail data items
|
Data Item
|
Description
|
|
Page Faults
|
This event represents the number of memory page faults occurring per second. A page fault occurs when an object necessary for a process to continue to run is not present in memory.
|
|
Overlay Candidates
|
This event represents the number of memory overlay candidates occurring per second. An overlay candidate is a memory object that has been flagged as temporarily non-essential, thus expendable to overwrite. This frees up memory for more urgent requests.
|
|
Posts
|
This event represents the number of times processes request memory pages to be posted to disc. This can be for file pieces, etc.
|
|
Pre-fetches
|
This event represents the total number of pre-fetch reads on behalf of processes. This event is similar to MPE V disc caching. More data is brought into memory than is essential so that future trips to disc can be avoided. Additionally, cumulative counters are available on the Tabular screen. You should watch these numbers over time to determine interpreting guidelines.
|
Tabular Format
The Tabular screen (
Figure 15.2) further breaks down memory events that occur on the system
by supplying cumulative values ([nn]) along with current interval statistics.
Figure 15.2 SOS Memory Detail screen (tabular format)
Memory Detail (tabular format)
The data items in the Memory Detail screen are described in the following table. The events are
those described in
Table 15.2.
Table 15.3 SOS Memory Detail data items
|
Data Item
|
Description
|
|
Tran Data
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by Transient Data.
|
|
Perm Data
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by Permanent Data.
|
|
NM Stack
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by a native mode stack.
|
|
CM Stack
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by a compatibility mode stack.
|
|
NM Code
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by a native mode programming code.
|
|
CM Code
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by compatibility mode programming code.
|
|
File Obj
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by File.
|
|
CM Xds
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by a CM_POST.
|
|
NM Sys
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by a native mode system task.
|
|
CM Sys
|
The number of events (within the current interval and cumulative) caused by memory waiting to complete for this process by a compatibility mode system task.
|
