Welcome!

IBM Cloud Authors: XebiaLabs Blog, Liz McMillan, Dana Gardner, Pat Romanski, Elizabeth White

Related Topics: IBM Cloud

IBM Cloud: Article

WebSphere Application Server for z/OS and zAAP: Manage Costs While Gaining Benefits

Take advantage of QoS features such as reliability, availability, scalability, and serviceability

Running applications in WAS for z/OS lets you take advantage of the z/OS built-in Quality of Service features such as reliability, availability, scalability, and serviceability. However, the solution could be very expensive.

J2EE applications and WAS for z/OS are very CPU-intensive workloads on z/OS. They consume a lot more CPU cycles than the traditional workloads running on z/OS, especially when processing big XML files.

Normally the CPU utilization of an application running on z/OS is measured in MIPS. An application consuming more CPU cycles means that the MIPS number for the application is higher. To provide more MIPS to run your application, more CPUs are needed. However, adding more CPUs to a zSeries server causes virtually all software license fees to go up because of the zSeries's software license model, which by the machine's CPU horsepower.

This is not a new story. Companies have been using different ways to manage the software cost on the zSeries platform for years. When the J2EE applications start running in WAS for z/OS, it's harder to manage the software cost than before.

To reduce the overall cost of enabling Java on zSeries platform, IBM introduced zAAP for Java workloads on z/OS. The following sections describe what a zAAP is, how it works, and how to use it.

What Is zAAP?
zAAP stands for zSeries Application Assist Processor, also known as the Integrated Facility for Application processor (IFA). It's a specialized processing unit (PU a k a CPU on open systems) available on the zSeries 990 (z990), 890 (z890), and z9. It provides a strategic z/OS Java execution environment for customers who want the powerful integration advantages and traditional QoS of the zSeries platform.

Conceptually, zAAP is just a co-processor like your old PC's floating-point co-processor. Instead of working as a standalone general processing unit (CP), it only assists the general-purpose CPs to execute Java programming under the control of the IBM JVM. For this reason, zAAP's capacity doesn't incur IBM or third-party software charges. So you can buy additional processing power exclusively for Java application execution without affecting the machine model designation that's used to determine zSeries software cost.

zAAP has been designed to operate asynchronously with general CPs to execute Java programming under control of the Java Virtual Machine (JVM). Executing IBM JVM processing cycles on a zAAP is a function of the IBM Software Developer Kit (SDK) for z/OS Technology Edition V1.4, z/OS V1R6, and the Processor Resource/System Manager (PR/SM).

Figure 1 is a z/OS Logical Partition with zAAP. One zAAP can be configured per general processor in a Central Electronic Complex (CEC).

zAAP is enabled by IBM's innovative zSeries PR/SM virtualization technology. It can be virtualized into logical zAAPs and assigned to different LPARs. But zAAPs and general CPs should exist in the same z/OS LPAR. On z990s or z890s, zAAPs are grouped in the ICF/IFL/zAAP processor pool. The ICF/IFL/zAAP processor pool appears on the hardware console as ICF processors. The number of ICFs shown is the sum of IFL, ICF, and zAAP processors characterized on the server.

To exploit a zAAP, the operating system must be migrated to the following levels of software:

  • z/OS V1R6
  • IBM JDK V1.4 with a PTF for APAR PQ 86689
  • For WAS for z/OS Java workloads, WAS for z/OS version 5.1 above
WAS for z/OS version 5.1 and above provide support for IBM's JDK 1.4. It makes WAS for z/OS one of the key workloads that can take advantage of zAAPs.

The z/OS exploitation of zAAP capabilities provides the following added values:

  • Simplifies and reduces server infrastructures by integrating e-business Java Web applications next to mission-critical data for QoS.
  • Maximizes the value of zSeries investment through increased system productivity, achieved by reducing the demands and capacity requirements on general CPs, which can be reallocated to other workloads.
  • With WAS for z/OS, your application can exploit the z/OS Workload Manager (WLM), which can guarantee service levels for specific kinds of customers and workloads defined by business needs.
In summary, zAAP is a special PU on the zSeries server that the Java workload can be off-loaded to. The applications you have running in WAS for z/OS can still leverage the QoS features provided by z/OS.

How Does zAAP Work?
When a z/OS logical partition is configured, both CPs and zAAPs are necessary to support the planned Java and non-Java workloads. Normally a Web application running in WAS for z/OS consists of both Java and non-Java workloads.

Figure 2 is the zAAP workflow. It essentially explains how the zAAP works. The IBM JDK V1.4 JVM, parts of Language Environment (LE) runtime, and z/OS Supervisor are needed to support JVM execution on zAAP.

Some of the JVM tasks are dispatched to general CPs. Basically these tasks do the following:

  • Determine if the program code is eligible to run on zAAP
  • Signal the z/OS dispatcher of the zAAP work
  • Handle the program code that's ineligible to run on zAAP
Other JVM tasks are dispatched to zAAPs. These tasks:
  • Determine if the program code is eligible to run on zAAP
  • Run the zAAP eligible program code
  • Signal z/OS dispatcher of non-zAAP work
Whenever a Java unit of work is executed, it's initially dispatched on a general CP. Before the Java code gets executed in the JVM, the JVM determines if the work is eligible to run on the zAAP. If so, the JVM signals the dispatcher that the current unit of work is zAAP-eligible. Then the dispatcher puts the current unit of work in the zAAP dispatcher queue. When a zAAP processor becomes available, the dispatcher selects the highest-priority work from the zAAP work queue and dispatches it on the zAAP processor.

A zAAP-eligible unit of work can be executed on a zAAP. zAAP work inherits the dispatching priority from the execution on the general CP. When the JVM finishes Java code processing, it signals the dispatcher that the current unit of work is not zAAP-eligible any more. The unit of work release control puts it back in the general logical processor work queue.

If the application is a pure Java application, the entire application should be run on the zAAP. Unfortunately, most applications that run in WAS for z/OS use various native libraries implicitly. For example, the JDBC type II driver, MQ batch adapter, and CTG for CICS Access are all Java code wrapprd around native codes. WAS for z/OS itself has other native code to exploit the z/OS environment. So you might see the dispatcher switch the work back and forth between the zAAP and the general CP. You can see in Figure 3 the zAAP integration at work. Switching the works back and forth causes overhead. Using zAAP reduces the MIPS number on general CPs, but the total MIPS number is higher than before.

More Stories By Linfeng Yu

Linfeng Yu is a software architect with ISO, Inc. He has extensive experiences in developing large-scale, complex enterprise-wide architectures and corss platform software development. He has been working with WebSphere for both distributed platform and z/OS since version 3.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
The IETF draft standard for M2M certificates is a security solution specifically designed for the demanding needs of IoT/M2M applications. In his session at @ThingsExpo, Brian Romansky, VP of Strategic Technology at TrustPoint Innovation, explained how M2M certificates can efficiently enable confidentiality, integrity, and authenticity on highly constrained devices.
In today's uber-connected, consumer-centric, cloud-enabled, insights-driven, multi-device, global world, the focus of solutions has shifted from the product that is sold to the person who is buying the product or service. Enterprises have rebranded their business around the consumers of their products. The buyer is the person and the focus is not on the offering. The person is connected through multiple devices, wearables, at home, on the road, and in multiple locations, sometimes simultaneously...
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
"We've discovered that after shows 80% if leads that people get, 80% of the conversations end up on the show floor, meaning people forget about it, people forget who they talk to, people forget that there are actual business opportunities to be had here so we try to help out and keep the conversations going," explained Jeff Mesnik, Founder and President of ContentMX, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
I wanted to gather all of my Internet of Things (IOT) blogs into a single blog (that I could later use with my University of San Francisco (USF) Big Data “MBA” course). However as I started to pull these blogs together, I realized that my IOT discussion lacked a vision; it lacked an end point towards which an organization could drive their IOT envisioning, proof of value, app dev, data engineering and data science efforts. And I think that the IOT end point is really quite simple…
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 19th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo Silicon Valley Call for Papers is now open.
You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
WebRTC is bringing significant change to the communications landscape that will bridge the worlds of web and telephony, making the Internet the new standard for communications. Cloud9 took the road less traveled and used WebRTC to create a downloadable enterprise-grade communications platform that is changing the communication dynamic in the financial sector. In his session at @ThingsExpo, Leo Papadopoulos, CTO of Cloud9, discussed the importance of WebRTC and how it enables companies to focus...
"My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
SYS-CON Events announced today that LeaseWeb USA, a cloud Infrastructure-as-a-Service (IaaS) provider, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LeaseWeb is one of the world's largest hosting brands. The company helps customers define, develop and deploy IT infrastructure tailored to their exact business needs, by combining various kinds cloud solutions.
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
ReadyTalk has expanded the capabilities of the FoxDen collaboration platform announced late last year to include FoxDen Connect, an in-room video collaboration experience that launches with a single touch. With FoxDen Connect, users can now not only engage in HD video conferencing between iOS and Android mobile devices or Chrome browsers, but also set up in-person meeting rooms for video interactions. A host’s mobile device automatically recognizes the presence of a meeting room via beacon tech...
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
It’s 2016: buildings are smart, connected and the IoT is fundamentally altering how control and operating systems work and speak to each other. Platforms across the enterprise are networked via inexpensive sensors to collect massive amounts of data for analytics, information management, and insights that can be used to continuously improve operations. In his session at @ThingsExpo, Brian Chemel, Co-Founder and CTO of Digital Lumens, will explore: The benefits sensor-networked systems bring to ...