IOSLICE parameter: Difference between revisions
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<dd><var class="product">Model 204 V6.1</var> or earlier | <dd><var class="product">Model 204 V6.1</var> or earlier | ||
</dl> | </dl> | ||
==Description== | ==Description== | ||
<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 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 <var>[[CPUSLICE_parameter|CPUSLICE]]</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> | The CPU time slice allotment, in milliseconds, for non-CPU-bound users</p> | ||
<p>A user voluntarily yields the CPU by any of the following actions: </p> | <p> | ||
This parameter determines which requests are considered CPU-bound. A user request is considered IO-bound unless <var>IOSLICE</var> milliseconds pass without the request voluntarily yielding the CPU. After <var>IOSLICE</var> milliseconds of CPU have been consumed, the user is considered CPU-bound. From this point, if <var>[[CPUSLICE_parameter|CPUSLICE]]</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> | |||
A user voluntarily yields the CPU by any of the following actions: </p> | |||
<ul> | <ul> | ||
<li> | <li> | ||
Executing a <var>[[Full- | 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> | <li> | ||
Requesting I/O to a <var class="product">Model 204</var> file or external sequential file</li> | Requesting I/O to a <var class="product">Model 204</var> file or external sequential file</li> | ||
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Going into a wait for a record or resource lock</li> | Going into a wait for a record or resource lock</li> | ||
</ul> | </ul> | ||
<p>Decreasing IOSLICE causes more requests to be considered CPU-bound, and increasing it causes fewer requests to be classed as CPU-bound.</p> | <p> | ||
<p>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. </p> | Decreasing <var>IOSLICE</var> causes more requests to be considered CPU-bound, and increasing it causes fewer requests to be classed as CPU-bound.</p> | ||
<p>For more information about | <p> | ||
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. </p> | |||
<p> | |||
For more information about CPU access, see [[Controlling system operations (CCAIN)#Dynamic dispatching|dynamic dispatching]]. </p> | |||
[[Category:Scheduler parameters]] | [[Category:Scheduler parameters]] | ||
[[Category:System parameters]] | [[Category:System parameters]] | ||
[[Category:Parameters]] | [[Category:Parameters]] | ||
Latest revision as of 21:18, 27 May 2016
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.
For more information about CPU access, see dynamic dispatching.