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Time Data

The Time Data section of the Measurement Session Data report shows all the processor and clock times in one report. The Time Data tab will not be displayed for those profiles with fewer than 100 samples.

Processor Time

  • CPU Time is the amount of time consumed by tasks executing in the measured job step, exclusive of the Strobe measurement task itself, expressed in minutes and seconds to the nearest hundredth. Since you are usually billed for the CPU time used, it is considered the most important measure of system resource time.

  • AS Enclave Time is address space enclave time, the CPU time consumed in a given address space for an enclave that is not included in the CPU field.

  • Independent Enclave Time is the amount of CPU time observed in independent enclaves. An independent enclave represents a complete transaction. Its performance goal is assigned based on the service class to which it is classified when the enclave is created. Each independent enclave starts in period 1 of its service class and switched periods based on the service consumed by dispatchable units belonging to the enclave.

  • Dependent Enclave Time is the amount of CPU time observed in dependent enclaves. A dependent enclave represents the continuation of an existing address space transaction under a new set of dispatchable units. Its performance goal is inherited from the existing address space transaction based on the service class (or PGN) and period being used to manage the address at the instant that the dependent enclave is created. CPU service consumed by a dependent enclave is treated as if it were consumed by the address space transaction, and can cause the address space along with the dependent enclave to switch to later periods.

  • SRB Time is the time, expressed in minutes and seconds to the nearest hundredth, during which the system was executing SRBs. SRBs represent high priority service routines. The Measurement Session Data report provides SRB time for your information and does not detail it in subsequent reports. Because Strobe measures while running as a task, it cannot measure activity running under an SRB. CPU, which is the aggregate task time for all Task Control Blocks (TCBs) in the address space, does not include SRB time. SRB time that is high relative to CPU could indicate an unusual or atypical type of processing and may warrant further investigation with other tools

  • Service Units are the amount of CPU execution activity observed during the measurement session. This measure of service units reflects one or more CPUs that were executing tasks in the measured job step, not including the measurement task itself. A service unit represents a normalized value of CPU power expressed as an instruction execution quantity. For the same amount of CPU time, a more powerful system will have a higher value in this field than a less powerful one.

Clock Time

  • Session Time is is the actual duration of the measurement session, expressed in minutes and seconds to the nearest hundredth. If the sample data set could not be closed properly (for example, because execution of the job in the address space was cancelled), a warning message appears in this area, and several related fields are blank.

  • Execution Time is the amount of run time during the measurement session that one or more CPUs were executing tasks in the measured job step, exclusive of the measurement task itself, expressed in minutes and seconds to the nearest hundredth.

  • Wait Time is the estimated portion of run time that no task within the measured address space was able to make use of the CPU time available to it, expressed in minutes and seconds to the nearest hundredth.

  • Stretch Time is the estimated amount of time that the CPU was unavailable to process programs executing in the address space because of demands by higher-priority address spaces and by SRB processing time for all address spaces. Stretch time may be high when multiple logical partitions (LPARs) are executing on the same complex of processors.

  • Multiprocessor Ratio is the amount of CPU time consumed divided by the execution run time, expressed as a decimal number to the nearest hundredths.