gtpm1m40 | TPF V4R1 Migration Guide: 3.1 to 4.1 |
This section discusses how to use the program event recording (PER) trace
facility.
If you are running VM instruction (PER) trace on 24-bit file-resident
programs, you may experience addressing problems (the SVM address may not be
the same as the EVM address, which you need for tracing). To run PER on
these programs, you need to temporarily reallocate them as common.
- Before you reallocate the program, enter the ZDPAT prog (where
prog is the program name) command to determine how the
program is currently allocated.
- To change the allocation to common, enter the ZAPAT prog
CLASS-COMMON command.
- Re-IPL the TPF 4.1 system so that the PAT is updated.
- Run PER trace.
- Change the allocation back to what it was before you ran PER (using the
ZAPAT command again)
- Re-IPL the TPF 4.1 system.
You can run the program event recording (PER) trace facility in a native
TPF 4.1 system. However, you should be careful when you use the
PER trace facility on a production system because it can seriously affect
system performance.
The following PER functions are supported for the TPF 4.1
system:
- Storage alteration
- Instruction fetching
- Successful branching (only on IBM ESA/390 processors).
- Note:
- In a test environment under an IBM Virtual Machine (VM) system,
use of the CP TRACE facility is recommended. The functions of the PER
trace facility that are provided in the TPF 4.1 system is a subset of
the ESA PER capability, and PER interrupts do not stop execution of the TPF
4.1 system. In addition, the CP Trace Facility is functionally
more productive.
- Use the ZSPER command to activate, end, and
display the status of the PER trace facility of IBM ESA processors.
- Use the PER user exit to change the output destination and the amount of
output or the format of output captured by a PER interrupt.