Reduce CPU time and improve performance

Document ID : KB000069163
Last Modified Date : 22/08/2018
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Introduction:

When there are no ASRs for a particular Environment to process, the launch sysparm
can logically disable the environment launches.  This results in reduced CPU time
and improved run time performance. 
 
 

Instructions:
The following sysparms control the launch of the Environments that are used during z/OS data set operations:
 
* SPECIFY N FOR ANY ENVIRONMENTS NOT USED - TO IMPROVE PERFORMANCE  *
PLSACS   (Y)             * LAUNCH ACS      ENVIRONMENT              
PLSLALLO (Y)             * LAUNCH ALLOC    ENVIRONMENT              
PLSLDEF  (Y)             * LAUNCH DEFINE   ENVIRONMENT              
PLSLEOV  (Y)             * LAUNCH EOV      ENVIRONMENT              
PLSLEOVV (Y)             * LAUNCH EOVVSAM  ENVIRONMENT              
PLSLEXT  (Y)             * LAUNCH EXTEND   ENVIRONMENT              
PLSLOLD  (Y)             * LAUNCH OLD      ENVIRONMENT              
PLSLPREA (Y)             * LAUNCH PREALLOC ENVIRONMENT              
PLSLREL  (Y)             * LAUNCH RELEASE  ENVIRONMENT              
PLSLRENM (Y)             * LAUNCH RENAME   ENVIRONMENT              
PLSLSCR  (Y)             * LAUNCH SCRATCH  ENVIRONMENT              
PLSLSPA  (Y)             * LAUNCH SPACE    ENVIRONMENT              

 
The default value of each of the launch sysparms is (Y), which causes each Environment
to launch for applicable allocation requests.  If you have no ASRs that do any processing
in an environment, then you logically disable that environment from launching by specifying
a value of (N) in your sysparm override member.  This command will refresh all Vkgparms:
F vam,PARMREF
Additional Information:
A major financial institution had been doing testing for a possible fix to improve performance. 
L2 asked the user to test the settings of one of these Vkgparms. 
The result of the test was:
 
PLSLPREA (N) - 20% decrease in Catalog CPU usage and a 25% reduction in Catalog I/O,
vs. when this Vkgparm was set to (Y).
 
Please see Knowledge Doc 49846 for information on other Vkgparms
that will improve CA Allocate performance.
 
If you have any questions, please contact CA Technical Support