APSYPAGE parameter: Difference between revisions
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<p>Activates the APSY Precompiled Procedures in Storage feature by specifying a number of 4K operating system pages.</p> | <p>Activates the APSY Precompiled Procedures in Storage feature by specifying a number of 4K operating system pages.</p> | ||
<p>For IBM z/OS systems only.</p> | <p>For IBM z/OS systems only.</p> | ||
<p>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 so it is recommended that customers disable the APSYPAGE feature by setting APSYPAGE to 0.</p> | |||
<p>When switching between using and not using APSYPAGE, the number of in-memory CCATEMP pages ([[TEMPPAGE parameter|TEMPPAGE]]) should be adjusted to compensate for the pages used or not used by APSYPAGE. That is, if APSYPAGE is set to zero, TEMPPAGE should be increased by the corresponding amount, and if APSYPAGE is set to a non-zero value, TEMPPAGE can be decreased by the corresponding amount. Note however, that the units for TEMPPAGE are 6184 ([[PAGESZ parameter|PAGESZ]]) bytes while the units for TEMPPAGE are 4096 (hardware page size) bytes so TEMPPAGE units should be multiplied by 1.5 to convert them to APSYPAGE units and APSYPAGE units should be divided by 1.5 to convert them to TEMPAGE units. 4096 times 1.5 actually equals 6144 but that's actually the amount used on each TEMPPAGE page — 40 bytes are used as page trailers and not used to hold actual data.</p> | |||
[[Category:System parameters]] | [[Category:System parameters]] | ||
[[Category:Parameters]] | [[Category:Parameters]] | ||
Revision as of 14:45, 22 September 2014
APSYPAGE is obsolete as of 7.6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 V6.1 or earlier
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 so it is recommended that customers disable the APSYPAGE feature by setting APSYPAGE to 0.
When switching between using and not using APSYPAGE, the number of in-memory CCATEMP pages (TEMPPAGE) should be adjusted to compensate for the pages used or not used by APSYPAGE. That is, if APSYPAGE is set to zero, TEMPPAGE should be increased by the corresponding amount, and if APSYPAGE is set to a non-zero value, TEMPPAGE can be decreased by the corresponding amount. Note however, that the units for TEMPPAGE are 6184 (PAGESZ) bytes while the units for TEMPPAGE are 4096 (hardware page size) bytes so TEMPPAGE units should be multiplied by 1.5 to convert them to APSYPAGE units and APSYPAGE units should be divided by 1.5 to convert them to TEMPAGE units. 4096 times 1.5 actually equals 6144 but that's actually the amount used on each TEMPPAGE page — 40 bytes are used as page trailers and not used to hold actual data.