
Cycle and Response Times
9-2
ET 200S IM 151-7 CPU Interface Module
A5E00058783-04
9.1 Cycle time
Cycle time – a definition
The cycle time is the time that the operating system requires to process a program
cycle – i.e. an OB 1 cycle – as well as all the program sections and system
activities interrupting this cycle.
This time is monitored.
Components of the cycle time
Factors Remarks
Operating system execution time See Table 9-1
Process image transfer time (PII and
PIQ)
See Table 9-2
User program execution time Is calculated from the execution times of the
individual instructions and a CPU-specific factor
(see Table 9-3).
Loading through interrupts See Table 9-4
The following figure shows the components that make up the cycle time:
PII
Operating
system
Cyclic user program
(OB 1)
PIQ
Interrupts
Operating
system
Acyclic user
program (e.g. OB
40/82)
Figure 9-1 Component parts of the cycle time
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