zAAPs are designed to operate asynchronously with the general purpose CPs to execute Java programming under control of the IBM Java Virtual Machine (JVM). This can help reduce the demands and capacity requirements on general purpose CPs which may then be available for real- location to other zSeries workloads. The amount of general purpose CP savings may vary based on the amount of Java application code executed by zAAP(s). And best
of all, IBM JVM processing cycles can be executed on the confi gured zAAPs with no anticipated modifi cations to the Java application(s). Execution of the JVM process- ing cycles on a zAAP is a function of the IBM Software Developer’s Kit (SDK) for z/OS Java 2 Technology Edition, z/OS 1.6 (or z/OS.e 1.6) and the innovative Processor Resource/Systems Manager™ (PR/SM™).
Notably, execution of the Java applications on zAAPs, within the same z/OS SMP LPAR as their associated database subsystems, can also help simplify the server infrastructures and improve operational effi ciencies. For example, use of zAAPs to strategically integrate Java Web applications with backend databases could reduce the number of TCP/IP programming stacks, fi rewalls, and physical interconnections (and their associated process- ing) that might otherwise be required when the application servers and their database servers are deployed on sepa- rate physical server platforms.
Essentially, zAAPs allow customers to purchase additional processing power exclusively for z/OS Java application execution without affecting the total MSU rating or machine
model designation. Conceptually, zAAPs are very similar to a System Assist Processor (SAP); they cannot execute an Initial Program Load and only assist the general purpose CPs for the execution of Java programming. Moreover, IBM does not impose software charges on zAAP capacity. Additional IBM software charges will apply when additional general purpose CP capacity is used.
Customers are encouraged to contact their specifi c ISVs/ USVs directly to determine if their charges will be affected.
z890 has a single model, the A04, and will support a wide performance range from sub uni models through to a 4- way multiprocessor. There will be a total of 28 capacity settings which will offer outstanding granularity for custom- ers' workload and cost management. The A04 model will provide up to four processor units (PUs) that can be char- acterized as either Central Processors (CPs), Integrated Facility for Linux (IFLs), Internal Coupling Facilities (ICFs) or zAAPs. This model will be offered as a new build and as upgrades from designated models of the z800.
With the introduction of the z890 customers can expect to see the following performance improvements with z/OS 1.4:
Number of CPs | Base | Estimated Ratio |
1 | z800 | 2.0 |
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2 | z800 | 2.1 |
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3 | z800 | 2.1 |
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4 | z800 | 2.1 |
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The Large System Performance Reference (LSPR) should be referenced when considering performance on the z890. Visit: ibm.com/servers/eserver/zseries/lspr/ for more infor- mation on LSPR.
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