Has anyone else experienced a similar problem?
This abend is a result of the z/VM Control Program (CP) being unable to acquire the IPTE Interlock in a reasonable time. The IPTE Interlock can be acquired by both CP and by Guests (running under SIE). The approach CP uses to acquire the lock is to try once every 50-100 microseconds for up to 10,000 attempts. If not acquired at the end of that, the LCK009 abend is taken. We have validated that the abend was not a result of the Guest holding the interlock indefinitely, but rather the rare timing that different vCPUs of the guest in question would acquire it in between CP's attempts to acquire it. The following are factors contributing to the possibility of resulting in the abend: 1. The rate at which the Guest is doing IPTEs. The higher the rate, the greater the possibility of the abend. 2. The number of virtual CPUs configured for a given virtual machine. Since IPTE can be issued by any of the virtual CPUs, the greater the number the greater the possibility. 3. The number of logical processors. Just having multiple virtual CPUs is not enough, but being able to run them concurrently increases the possibility. 4. Load on the system by other guests. The lighter the load overall, the more likely multiple vCPUs of the same guest could be dispatched at once and the greater the possibility. 5. Frequency at which CP attempts to acquire the lock. Currently 50-100 microseconds. The less frequently CP attempts to acquire the lock, the more likely CP misses an opportunity where the lock was available. -- George Henke (C) 845 401 5614 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
