This is the third installment in a series of articles to give you a z Systems perspective on InterConnect 2015. This article will focus on Java V8 performance on new z13 hardware WebSphere Application Server performance on z/OS and news related to specialty engines on z Systems.

The fourth and last article in this series will cover WebSphere Liberty on z/OS WAS Liberty and Java Batch CICS Transaction Server & Transaction Gateway announcements and z/OS Connect.

For other z Systems news out of InterConnect check out Part 1, Part 2 and Part 4 of this series. 

Why You Should Rethink Java on z

This year I had the pleasure and privilege to co-present at InterConnect with Marcel Mitran (IBM) during session ASZ-2026 "Reasons to Love IBM Java and WebSphere Application Server on z Systems.” This was one of the most well-attended z Systems breakout sessions.

Mitran outlined the latest in innovation and performance with IBM z13 and Java 8. I presented HCSC’s (the largest customer-owned health insurer in the U.S.) WAS on z/OS V8.5.5 x performance data using Java V6.0.1 and Java V7.1 lessons learned and best practices information.

Mitran explained how Java is a critically important language for IBM z Systems. For data serving and transaction serving which are traditional strengths of z Systems Java has become foundational. For instance WebSphere applications written in Java and running on z Systems provide a key advantage through co-location better response times greater throughput and reduced system complexity when driving CICS IMS and DB2 transactions. Beyond this as clients seek to extend and modernize their business logic Java has become a language of choice for CICS IMS and DB2 transactions.  

At HCSC we took advantage of co-location performance benefits on z Systems with tight integration with DB2 MQ and CICS. We observed 3X to 4X performance improvement for one of our largest WebSphere on z/OS applications which was moved from WAS on distributed platform to WAS on z/OS.

Java is also critical for enabling next-generation workloads in cloud analytics mobile and security. Cloud and mobile applications can access data and transactions on z/OS using z/OS Connect and other WebSphere solutions which are all inherently Java based. IBM Operational Decision Manager is written in Java. ODM is a platform for managing and executing business rules and business events to help make decisions faster improve responsiveness minimize risks and seize opportunities. The IBM MobileFirst Platform Developer Edition formerly known as IBM Worklight Developer Edition provides developers with the tools to quickly deploy mobile solutions using Java. Java on z Systems also provides a full set of cryptographic functions to implement secure solutions.

 

Here is a summary of HCSC’s experience with WAS on z/OS upgrading to V8.5.5.x –

• Migrating from WAS on z/OS V7.0 to V8.5.5.x using Java V6.0.1 resulted in up to 30 percent CPU saving depending on what functionally your application is using
• Applications with the small Heap size benefited running in 31 bit mode vs 64 bit mode
• Taking advantage of Pageable Large Page Support and Flash Express we saw a 4.4 percent CPU reduction           
• Tuning our JVMs for optimum performance we saw over a 10 percent CPU reduction 
• Upgrading to WAS on z/OS V8.5.5.2 and  taking advantage of Java V7.1 we observed a 20percent throughput improvement and a 10-12percent CPU reduction
• We analyze GC performance with PMAT and watch out for Java OOM conditions which can increase CPU usage considerably due to excessive GC overhead

The great performance improvements HCSC took advantage of do not stop with Java V7.1.  IBM has made significant performance improvements in Java V8 on z13 which were just announced on March 6. A key strength of Java applications is the ability to immediately benefit from the latest hardware performance improvements using the Just In-Time compiler in the latest Java SDK release. The chart below shows a significant set of new hardware features in z13 that are co-designed with Java. 

 

Mitran presented very impressive performance data comparing Java V7.0 V7.1 and V8 on zEC12 and z13 hardware showing a 2.6X improvement in throughput comparing Java 7 SR4 on zEC12 to Java 8 on z13 using SMT shown below.

 

Find out more in this related article “Java performance on IBM z Systems: IBM z13 and IBM Java SDK 8” written by IBM’s Clark Goodrich Marcel Mitran and Bob St John.

Specialty Engines on z Systems

You can take advantage of the following specialty engines on z Systems:

• zAAP (Application Assist Processor) -  Specialized processing engine that provides a strategic z/OS Java and is used by WebSphere Application server running on z/OS.

• zIIP (Integrated Information Processors) - Provides an execution environment that accepts eligible work from z/OS. Workload Manager on z/OS (WLM) manages and directs the work between the General Purpose (CP) processor and zIIP specialty engines. DB2 for z/OS exploits the zIIP capability for portions of eligible workloads.  

• IFL (Integrated Facility for Linux) - Allows you to purchase additional processing capacity for Linux on z Systems workloads without increasing IBM software charges for the existing z Systems environment.

The benefits of using specialty engines:

• Much lower acquisition and maintenance costs when compared with CP
• zAAP/zIIP engines run at full-rated CP speed
• Offload work (CPU) from CP engines provides more CP for other work
• Offload of work to specialty engines is transparent to applications
• No cost for sub-capacity eligible IBM software
• Lowers the overall cost of computing for WebSphere Application Server and other Java technology-based applications through hardware software and maintenance savings

IBM has modified the ratio of zIIP/zAAPs to CPs to be 2:1 for a zEC12 and/or zBC12. For z196 and z114 and older a zIIP to CP ratio is still of no more than 1:1; the number of zIIPs cannot exceed the number of CPs. 

IBM zEC12 and zBC12 are planned to be the last z Systems servers to offer support for zAAP specialty engine processors. IBM intends to continue support for running zAAP workloads on zIIP processors (zAAP on zIIP). Consider planning for further use of zIIPs or alternatively zAAPs on zIIPs.

Beginning with z/OS V1.11 z/OS added a capability that can enable zAAP-eligible workloads to run on zIIPs so that you can run both zIIP- and zAAP-eligible workloads on the zIIP. You also need to be aware that if you are using zAAP engines now and turn off crossover to CP you will lose the ability to disable crossover when using zAAP on zIIP.

If you are looking to upgrade to new z13 hardware you will be able to reduce TCO for specialty engines. IBM continues the practice of advantageously pricing specialty engines that are carried forward in an upgrade at 30 percent of the street price for a new specialty engine when upgrading from a zEC12 (n-1) and at 60 percent when upgrading from a z196 (n-2). Assuming that the street price does not change i.e. from $55000 and $100000 for an IFL and zIIP respectively the upgrade price for an IFL will be $16500 and $33000 when upgrading from a zEC12 and a z196 respectively. Given the additional performance of the IFL and the zIIP on the z13 this is an extremely aggressive price/performance ratio for the incremental capacity.

This presentation can be downloaded from Chicago North-West Integration and Cloud Computing WebSphere User Group site here. Related information on z13 can found in the Clipper Group report "The IBM z Systems and the New IBM z13  - Ready to Transform Your Enterprise."