Comparison between Independent, Dependent and Work-dependent Enclaves

You use independent, dependent and work-dependent enclaves for different purposes, as follows:

• Independent Enclaves

  Use an independent enclave to represent a new transaction. The TYPE=INDEPENDENT parameter on IWM4ECRE is the default. An independent enclave must be classified into a service class or performance group when it is created, so the caller must provide classification qualifiers as input to IWM4ECRE. The home address space when IWM4ECRE is issued is the owner of an independent enclave. CPU service consumed by the enclave is accumulated in the SMF 30 record of the owning address space and the SMF 72 record of the enclave's service class or performance group period.

  For an independent enclave, the connect token provided with the CLSFY keyword of macro IWM4ECRE must not be associated with a user key (as specified with the CONNTKNKEY parameter of IWM4CON, or IWMCONN).

  For examples showing how to use independent enclaves, see Scheduling an SRB in an Independent Enclave and Joining Tasks to an Independent Enclave.

• Dependent Enclaves

  Use a dependent enclave when you have an existing address space defined with its own performance goal that you wish to extend to programs running under dispatchable units in other address spaces. For a dependent enclave that is created with TYPE=DEPENDENT specified on IWM4ECRE, the owner will become the home address space at the time the service is invoked. The owner address space of a dependent enclave, resulting from IWM4ECRE with TYPE=WORKDEPENDENT specified, will be the creating enclave's (that is, the enclave the TCB/SRB was running in when it called IWM4ECRE) owner. A dependent enclave derives its performance goal from the owning address space, and all CPU service consumed by the enclave is accumulated in the SMF 30 record of the owning address space and the SMF 72 record of the owning address space's service class or performance group period.

  The TYPE=MONENV parameter creates a dependent enclave owned by the address space of a specified monitoring environment. Note that this dependent enclave is managed to the goal established for the owning address space, not the response time goal that might have been established for the monitoring environment.

  For an example showing how to use dependent enclaves, see Using Dependent Enclaves.

• Work-dependent Enclaves

  Use a work-dependent enclave to extend an existing independent enclave's transaction. A work-dependent enclave inherits its classification and its owner address space from the independent enclave it extends. CPU service consumed by the enclave is accumulated in the SMF 30 record of the owning address space and the SMF72 record of the enclave's service class.

For more specific differences between independent, work-dependent and dependent enclaves, see Table 12.