System trace tables reside in fixed storage on each processor.
The default trace table size is
1 MB per processor, but you
can change it using the TRACE ST command. You might, however, want
to increase the size of the system trace table from the default
1
MB when:
- You find that the system trace does not contain tracing from a
long enough time period.
- You want to trace branch instructions (using the BR=ON option
on the TRACE ST command when you start tracing).
Do the following to increase the size of the trace table:
- Enter the TRACE ST command to change the size of the system trace
table. For example, to restart system tracing and increase the size
of the trace table from the default 1 megabyte per processor to
2 megabytes per processor:
TRACE ST,2M
- Enter the TRACE ST command with the BUFSIZE (or BUFSIZ) parameter
to change the total size of the system trace table allocated. For
example, in a system that has 10 processors, to restart system tracing
and increase the size of the trace table from the default of 10
megabytes (1 megabytes per processor) to 20 megabytes (2 megabytes
per processor):
TRACE ST,BUFSIZ=20M
Remember: Choose a reasonable value for the system trace
storage after considering the available central storage and the actual
storage required for system trace. Increasing the system trace storage
to a large value amount may cause shortage of pageable storage in
the system.