APSYPAGE parameter: Difference between revisions

From m204wiki
Jump to navigation Jump to search
No edit summary
Line 21: Line 21:
<p>
<p>
<var>APSYPAGE</var> was implemented to take advantage of the <code>MVPG</code> machine language instruction which moved an entire hardware page (4K) with a single instruction and which, at the time, had significantly better performance than the stream-oriented moves used by standard APSY load. However, recent hardware models actually seem to have better performance for the stream-oriented moves.</p>
<var>APSYPAGE</var> was implemented to take advantage of the <code>MVPG</code> machine language instruction which moved an entire hardware page (4K) with a single instruction and which, at the time, had significantly better performance than the stream-oriented moves used by standard APSY load. However, recent hardware models actually seem to have better performance for the stream-oriented moves.</p>
<p>Therefore, it is now recommended that customers using the APSYPAGE parameter <var class="term">disable the APSYPAGE feature</var> by setting <var>APSYPAGE</var> to 0.</p>
<p>Therefore, it is now recommended that customers who have been using the <var>APSYPAGE</var> parameter <var class="term">disable the APSYPAGE feature</var> by setting <var>APSYPAGE</var> to 0. Then set the <var>[[RESPAGE parameter|RESPAGE]]</var> parameter to the former value of APSYPAGE.</p>


<p>When switching between using and not using <var>APSYPAGE</var>, the number of in-memory CCATEMP pages (<var>[[TEMPPAGE parameter|TEMPPAGE]]</var>) should be adjusted to compensate for the pages used or not used by <var>APSYPAGE</var>. That is, if <var>APSYPAGE</var> is set to zero, <var>TEMPPAGE</var> should be increased by the corresponding amount, and if <var>APSYPAGE</var> is set to a non-zero value, <var>TEMPPAGE</var> can be decreased by the corresponding amount. </p>
The units for both <var>RESPAGE</var> and <var>APSYPAGE</var> are 4096 (hardware page size) bytes.
 
<blockquote class="note"><b>Note:</b> The units for <var>TEMPPAGE</var> are 6184 (<var>[[PAGESZ parameter|PAGESZ]]</var>) bytes while the units for <var>APSYPAGE</var> are 4096 (hardware page size) bytes.
 
Multiply <var>APSYPAGE</var> units by 1.5 to convert them to <var>TEMPPAGE</var> units.
Divide <var>TEMPPAGE</var> units by 1.5 to convert them to <var>APSYPAGE</var> units.
 
(4096 times 1.5 equals 6144, but that is actually the amount used on each <var>TEMPPAGE</var> page &mdash; 40 bytes are used as page trailers and not used to hold actual data.)</blockquote>


[[Category:System parameters]]
[[Category:System parameters]]
[[Category:Parameters]]
[[Category:Parameters]]

Revision as of 20:10, 13 January 2016

APSYPAGE is obsolete as of 7.6

Summary

Default value
0
Parameter type
System
Where set
On User 0's parameter line
Related products
All
Introduced
Model 204 V5.1

Description

Activates the APSY Precompiled Procedures in Storage feature by specifying a number of 4K operating system pages.

For IBM z/OS systems only.

APSYPAGE was implemented to take advantage of the MVPG machine language instruction which moved an entire hardware page (4K) with a single instruction and which, at the time, had significantly better performance than the stream-oriented moves used by standard APSY load. However, recent hardware models actually seem to have better performance for the stream-oriented moves.

Therefore, it is now recommended that customers who have been using the APSYPAGE parameter disable the APSYPAGE feature by setting APSYPAGE to 0. Then set the RESPAGE parameter to the former value of APSYPAGE.

The units for both RESPAGE and APSYPAGE are 4096 (hardware page size) bytes.

Retrieved from "https://m204wiki.rocketsoftware.com/index.php?title=APSYPAGE_parameter&oldid=82364"