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 READ SCREEN, READ MENU, or <var>[[$READ|$READ]]</var> statement</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>
<li>
Requesting I/O to a <var class="product">Model&nbsp;204</var> file or external sequential file</li>
Requesting I/O to a <var class="product">Model&nbsp;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 <var class="product">Model&nbsp;204</var> dynamic dispatching, see the <var>Model&nbsp;204 System Manager's Guide</var>. </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>
<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.