UIOSLIC parameter: Difference between revisions
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The CPU time slice allotment, in milliseconds, for non-CPU-bound users</p> | The CPU time slice allotment, in milliseconds, for non-CPU-bound users</p> | ||
<p> | <p> | ||
This parameter determines which requests are considered CPU-bound. A user request is considered IO-bound unless <var>UIOSLIC</var> milliseconds pass without the request voluntarily yielding the CPU. After <var>UIOSLIC</var> milliseconds, the user is considered CPU-bound. From this point, if <var>[[ | This parameter determines which requests are considered CPU-bound. A user request is considered IO-bound unless <var>UIOSLIC</var> milliseconds pass without the request voluntarily yielding the CPU. After <var>UIOSLIC</var> milliseconds, the user is considered CPU-bound. From this point, if <var>[[UCPUSLIC parameter|UCPUSLIC]]</var> milliseconds expire without yielding the CPU, the user is time sliced (forced to yield the CPU to the user with the next highest priority). </p> | ||
<p> | <p> | ||
A user voluntarily yields the CPU by any of the following actions: </p> | A user voluntarily yields the CPU by any of the following actions: </p> | ||
<ul> | <ul> | ||
<li>Executing a [[Full- | <li>Executing a <var>[[Full-screen feature#READ SCREEN statement|READ SCREEN]]</var>, <var>[[Full-screen feature#READ MENU statement|READ MENU]]</var>, or <var>[[$Read]]</var> statement </li> | ||
<li>Requesting I/O to a <var class="product">Model 204</var> file or external sequential file</li> | <li>Requesting I/O to a <var class="product">Model 204</var> file or external sequential file</li> | ||
Latest revision as of 19:34, 16 October 2017
User I/O slice
Summary
- Default value
- 30
- Parameter type
- System
- Where set
- On user's parameter line by system manager
- Related products
- All
- Introduced
- Model 204 V7.1
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 UIOSLIC milliseconds pass without the request voluntarily yielding the CPU. After UIOSLIC milliseconds, the user is considered CPU-bound. From this point, if UCPUSLIC 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.
For more information about Model 204 dynamic dispatching, see Dynamic dispatching.