z/OS Memory Objects

The z/OS Memory Objects report appears when Strobe encounters z/OS memory objects. It identifies memory objects created by an application that are present when measurement takes place. This report will never contain more than 40 memory objects.

Report details

The following terms define the content of each column in the report.

Source shows from where or how the limit was set.
Job Memory Limit shows the maximum amount of virtual storage (megabytes) that can be allocated in the address space.

Observed tab

First: Lists the memory objects Strobe first detects during measurement.
Highest Usable Memory: If Strobe detects a higher count of memory objects between the first and last observations, data for these memory objects is shown here
Last: Lists the memory objects Strobe detects during its last measurement observation.

For each of these types of memory objects, the report shows:

High Water Mark (MB) shows the largest amount of 64-bit storage that has been allocated in the measured address space from address space creation. This value may not reflect observed values for the address space during the measurement session. This value is not reported for batch jobs because it may not accurately reflect the actual 64-bit storage use of the current batch job.
Size (MB) shows how many megabytes were allocated to the object.
Guard Bytes (MB) shows in megabytes the amount of storage used as a reserve for future use, or protection from inadvertent overlays originating from adjacent objects. This amount is not accessible unless subsequently changed. Loc indicates the location of the guarded bytes.
Usable Memory (MB) shows in megabytes the amount of memory available after subtracting the guard bytes from the size of the object.

Click next to an Observation to view additional detail for each memory object:

Origin Address shows the originating address of the memory object.
User or Creator indicates if the request to create the object came from the measured address space, i.e. the Creator ASID is that of the measured address space. User indicates the measured address space did not create the object.
Requestor shows the source of the object allocation.
- Name shows the name of the program which issued the request to allocate the memory object.
- Offset shows the displacement in the program of the request to allocate the memory object.
Creator ASID shows the address space identifier from which the request to allocate the object came.
Status indicates the state of the caller that made the call.
User Token shows the user token value that can be used to group memory objects on a DETACH request.
- Type indicates the type of token passed.
- Name shows the value used on the USRTKN (or TTOKEN?) parameter
Storage Protection shows the protection attributes of the object.
- Key shows the storage protection key required to read and write data in the object.
- FP indicates if the PSW key must match the storage key in order to reference (read) data in the object.
SVC Dump shows whether the memory object storage will be dumped when SVC dump SDATA includes RGN.
Usable Memory (MB) shows the amount of usable memory available for the object.

The Delta Section shows the differences between the summary values among the time frames:

First to last
First to highest usable
Highest usable to last