Performance Management of Address Spaces with Enclaves
This information describes the performance management of address
spaces with enclaves in terms of MPL level, paging, dispatching, and
I/O priorities.
Address spaces with enclaves (dependent enclaves or independent
enclaves) are managed either towards the performance goal of the address
space or towards the performance goal of the enclave depending on
how the program associates the enclave with the address space. In
either case, the enclave's dispatching priority is always managed
towards the performance goal of the enclave.
Table 11. Performance management of address spaces with enclaves| Managing performance towards the performance
goal of the address space | Managing performance towards the performance
goal of the enclave |
|---|
| Address spaces are managed towards the performance
goal of the address space if an enclave SRB
was scheduled to run in this address space without the enclave being
associated to the address space (the SRB did not issue SYSEVENT ENCASSOC).
In
this case, the non-enclave work is also managed
towards the performance goal of the address space.
Note:
An address space must be non-swappable if it has enclave
SRBs dispatched and SYSEVENT ENCASSOC has not been issued. | Address spaces are managed towards the performance
goal of the enclave, if one of the following
is true:
- At least one task of the address space has joined an enclave by
the services IWMEJOIN or IWM4STBG having been issued, or
- At least one enclave SRB was scheduled to run in this address
space that has issued the SYSEVENT ENCASSOC to associate the enclave
with this address space.
Note that the performance management of the non-enclave
work depends on the specification of the IEAOPT parameter ManageNonEclaveWork:
- For ManageNonEnclaveWork=NO and for Releases
earlier than z/OS® R12:
It is assumed that no work consuming significant CPU service is running
in the address space outside of an enclave. The CPU consumption of
work running outside of enclaves is not included when Workload Management
assesses the impact of CPU adjustments for the enclave work.
- For ManageNonEnclaveWork=YES: The
non-enclave work of an address space is performance managed towards
the first service class period of the address space goal. Based on
this expanded performance management it is recommended to verify the
performance goals for the service class of the address spaces which
process enclave work. See Figure 11 for an example.
Refer to z/OS MVS Initialization and Tuning Reference
for further information about the OPT parameter. | Figure 11 shows an example of how the non-enclave
work of Task F is managed towards the first period of the service
class A (SC A) which is the address space goal.
Figure 11. Performance Management of Non-Enclave Work with OPT parameter ManageNonEnclaveWork=YES - Example
|
z/OS MVS Programming: Workload Management Services
Copyright IBM Corporation 1990, 2014