Received dump TITLE CA/XMANAGER 20.0 PXMQMGCC in Xmanager

Products

• Detector for DB2 for z/OS
• Subsystem Analyzer for DB2 for z/OS
• Database Management for DB2 for z/OS - Performance Suite

Issue/Introduction

What is the cause the following dump noted for Database Management for Db2 for z/OS Xmanager:
TITLE=CA/XMANAGER 20.0 PXMQMGCC FAILURE DIAG/DUMP

Resolution

This concern appears to be related to an Xmanager dispatching issue.  There was no evidence of a loop.

The Xmanager address spaces dispatching priority is set to X’F0’ the Db2 address spaces are set to x’F8’.  The Xmanager dispatching priority needs
to have a dispatching priority the same or higher than the Db2 address spaces.  This is especially true when using the Detector collection tasks.

The hlq.CDBAPARM collection tasks are set up to run on a zIIP.  The documentation shows that the zIIPs utilization is 100% and the general purpose CPUs are at 66%.
The IEAOPT parameters appear to be set to allow the collection task to fall back and run on a CPU but that did not occur in a timely manner. 
The work dispatched on the zIIPs is probably a higher dispatching priority than the Xmanager address space.

The recommendation is to increase the dispatching priority of the Xmanager address space to be the same or higher than the Db2 address spaces.