A fix is available
APAR status
Closed as program error.
Error description
You use CPSM WLM to route work from routing regions ( TOR ) to target regions ( AOR ). All the AORs are equally favorable. That is, they have the same 'AOR Weight'. When this happens, CPSM should randomize the selection of equally favorable target regions so that the workload gets distributed as evenly as possible. Due to the way the randomization routine is currently designed, this may not always happen. . . Additional Symptom(s) Search Keyword(s): KIXREVSVR z14 upgrade2z14 D/T3906 z15 upgrade2z15 z16 upgrade2z16
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICSPlex SM V5R1M0, V5R2M0, V5R3M0 and * * V5R4M0 Users. * **************************************************************** * PROBLEM DESCRIPTION: After upgrading to a z14 machine, CPSM * * WLM routing distribution patterns from * * routing regions running on the z14 may * * appear different than on previous * * machines. * * * * The different behavior will be more * * apparent when using CPSM Sysplex * * Optimized WLM processing. * **************************************************************** * RECOMMENDATION: After applying the PTF that resolves this * * APAR, all MASes running as CPSM WLM routing * * regions must be recycled to pick up the new * * code. * **************************************************************** When a route request is received in a CPSM WLM routing region, it builds a list of all target regions that are in the scope of the route (Scope Vector), and associates a weight with each target region based upon task load, connection type and health factors, where the lower weight indicates the best available target region for the route. After building the Scope Vector, it is sorted low to high, and the target region with the lowest weight is selected for the route. If more than one target region has the same lowest weight, then CPSM uses a randomization process to select one of the lowest weight tied target regions. This randomization process is performed by method EYU0WASV (WASV), and has been determined to be invalid for use with z14 machine processing, resulting in some tied for lowest weight target regions getting more work than other regions. The worse case scenario is when the same two target regions are tied for lowest weight. In this situation, the same one will most likely be always chosen. While the randomization process does not work properly with z14 machines in all situations, it is more likely to be evident when CPSM Sysplex Optimized WLM is in use, since the task load is a tiered value instead of an absolute value, which can keep a target region's load constant while it receives multiple routes.
Problem conclusion
WASV has been updated to change the randomization process so that it works properly in z14 and earlier machines.
Temporary fix
Comments
APAR Information
APAR number
PI90941
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
00M
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2017-11-30
Closed date
2018-01-31
Last modified date
2022-08-29
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
PI91168 UI53576 UI53577 UI53578 UI53579
Modules/Macros
EYU0WASV
Fix information
Fixed component name
CICS TS Z/OS V5
Fixed component ID
5655Y0400
Applicable component levels
R00M PSY UI53579
UP18/02/01 P F801 ¢
R10M PSY UI53578
UP18/02/01 P F801 ¢
R80M PSY UI53576
UP18/02/02 P F802 ¢
R90M PSY UI53577
UP18/02/02 P F802 ¢
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
29 August 2022