Detecting LOOPs with SYSVIEW

Products

• SYSVIEW Performance Management

Issue/Introduction

Is it possible to detect LOOP using SYSVIEW?

Also, are there any metrics or features that detect loops?

Environment

OS : z/OS

Release : All

Resolution

We can accomplish loop detecting in one of few ways.

(1) It is possible to use the Total CPU% metric (MVS_JOB_CpuTotalPct).  This metric represents the CPU% consumed by a job during the collection interval times the number of CPUs. A value of 150% for example indicates that the job use the equivalent one and a half CPUs during the data collection interval. 

(2) Using Conditions, it is possible to use fields CPUT% and JSACT% from the ACTSUM display. The JSACT% represents the percentage of time during the collection interval the job was active on the processor. For example, ValueOf CPUT% > 100% AND ValueOf  JSACT% > 80 indicates that the job used one full processor and was active 80% of the time during the collection interval. This may be in indication that the job is looping. 

(3) Using the CPU% and I/O rate as we can pointed out.