IBM MQ for z/OS and offloading to specialty processors
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What are specialty processors?
From the IBM System z9 server, IBM introduced 2 types of specialty processors, zIIP and zAAP.
The IBM z Systems Integrated Information Processor (zIIP) is designed to help free-up general computing capacity and lower the overall total cost of computing for select data and transaction processing workloads for business intelligence (BI), ERP and CRM, and select network encryption workloads on the mainframe.
The IBM z Systems Application Assist Processors (zAAP) are designed to provide an environment for web-based applications and SOA-based technologies such as Java™.
From the IBM z13, zIIP specialty engines will also run workloads that are eligible to run on zAAP specialty engines.
zIIPs and zAAPs are designed to work asynchronously with the general processors to execute Java programming under control of the IBM Java Virtual Machine (JVM), and this can help reduce capacity requirements on general purpose processors, which in turn may be available for reallocation to other mainframe workloads.
The amount of general purpose processor savings will vary based on the amount of Java application code executed by zAAPs (or zIIPs).
How does MQ benefit from zIIP (or zAAP)?
Typically the queue manager, channel initiator or AMS address spaces will not directly benefit from zIIP or zAAP availability - instead it is the applications connecting to MQ that can benefit from being offloaded to the specialty processors.
Of course, this offloading does potentially reduce the load on the general purpose processors which can have a positive effect on those address spaces that are unable to use specialty processors.
Within MQ there are some areas which can exploit specialty processors:
Anything else to consider?
Not all of the Java/JMS workload will always be offloaded - some of the work may not be eligible, or there may not be a suitable specialty processor available.
For example, if the zIIP(s) are busy, your zIIP-eligible workload may be run on a general purpose processor, although there are 3 IEAOPTxx parameters which may be of interest
IBM's System z z13 introduced the use of simultaneous multi-threading (SMT) to execute 2 instruction streams (or threads) on a processor core for zIIP-eligible workload. The CICS redbook "IBM