IOSLICE parameter
CPU slice - IO
Summary
- Default value
- 30
- Parameter type
- System
- Where set
- On User 0's parameter line or reset by system manager
- Related products
- All
- Introduced
- Model 204 V6.1 or earlier
Description
The CPU time slice allotment, in milliseconds, for non-CPU-bound users
This parameter determines which requests are considered CPU-bound. A user request is considered IO-bound unless IOSLICE milliseconds pass without the request voluntarily yielding the CPU. After IOSLICE milliseconds of CPU have been consumed, the user is considered CPU-bound. From this point, if CPUSLICE milliseconds expire without yielding the CPU, the user is time sliced (forced to yield the CPU to the user with the next highest priority).
A user voluntarily yields the CPU by any of the following actions:
- Executing a READ SCREEN, READ MENU, or $READ statement
- Requesting I/O to a Model 204 file or external sequential file
- Going into a wait for a record or resource lock
Decreasing IOSLICE causes more requests to be considered CPU-bound, and increasing it causes fewer requests to be classed as CPU-bound.
Increasing this parameter diminishes the impact of dynamic dispatching, thus allowing CPU-bound requests to monopolize the CPU. Decreasing this parameter heightens the effect of dynamic dispatching, resulting in increased scheduler overhead.
See the following section for more information about dynamic dispatching.