EXSPATxx (excessive spin condition actions)

The EXSPATxx member allows an installation to specify actions to be taken to recover from excessive spin conditions without operator involvement. A system routine might be spinning because it cannot obtain a resource held by another processor. EXSPATxx allows you to specify the action or actions to be taken to end the spin loop if the excessive spin is detected while spinning for one of the following:

A RISGNL response
A spin lock to be released
A successful BIND BREAK completion
The RESTART resource
An address space to quiesce
An INTSECT release
A CPU in the stopped state.

EXSPATxx does not support actions for spin loops that are caused by SIGP failures.

The IBM-supplied defaults for the system are appropriate in a normal environment. In a test environment, however, you might want to specify particular actions to be taken.

In addition to recovery actions, EXSPATxx allows you to specify a timeout interval. If an excessive spin continues beyond the timeout interval, the system automatically issues a SPIN action before taking any recovery action specified in an EXSPATxx member. If the excessive spin continues until the timeout interval is reached again, then the recovery actions specified in the EXSPATxx member are taken.

For more information about handling excessive spin conditions, see z/OS MVS Setting Up a Sysplex