Welcome!

IBM Cloud Authors: Pat Romanski, Carmen Gonzalez, Elizabeth White, Yeshim Deniz, Jnan Dash

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
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2017 New York. The 20th Cloud Expo and 7th @ThingsExpo will take place on June 6-8, 2017, at the Javits Center in New York City, NY. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Internet to enable us all to im...
Extracting business value from Internet of Things (IoT) data doesn’t happen overnight. There are several requirements that must be satisfied, including IoT device enablement, data analysis, real-time detection of complex events and automated orchestration of actions. Unfortunately, too many companies fall short in achieving their business goals by implementing incomplete solutions or not focusing on tangible use cases. In his general session at @ThingsExpo, Dave McCarthy, Director of Products...
"At ROHA we develop an app called Catcha. It was developed after we spent a year meeting with, talking to, interacting with senior citizens watching them use their smartphones and talking to them about how they use their smartphones so we could get to know their smartphone behavior," explained Dave Woods, Chief Innovation Officer at ROHA, in this SYS-CON.tv interview at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
We are always online. We access our data, our finances, work, and various services on the Internet. But we live in a congested world of information in which the roads were built two decades ago. The quest for better, faster Internet routing has been around for a decade, but nobody solved this problem. We’ve seen band-aid approaches like CDNs that attack a niche's slice of static content part of the Internet, but that’s it. It does not address the dynamic services-based Internet of today. It does...
The many IoT deployments around the world are busy integrating smart devices and sensors into their enterprise IT infrastructures. Yet all of this technology – and there are an amazing number of choices – is of no use without the software to gather, communicate, and analyze the new data flows. Without software, there is no IT. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Dave McCarthy, Director of Products at Bsquare Corporation; Alan Williamson, Principal...
"ReadyTalk is an audio and web video conferencing provider. We've really come to embrace WebRTC as the platform for our future of technology," explained Dan Cunningham, CTO of ReadyTalk, in this SYS-CON.tv interview at WebRTC Summit at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
IoT solutions exploit operational data generated by Internet-connected smart “things” for the purpose of gaining operational insight and producing “better outcomes” (for example, create new business models, eliminate unscheduled maintenance, etc.). The explosive proliferation of IoT solutions will result in an exponential growth in the volume of IoT data, precipitating significant Information Governance issues: who owns the IoT data, what are the rights/duties of IoT solutions adopters towards t...
WebRTC is the future of browser-to-browser communications, and continues to make inroads into the traditional, difficult, plug-in web communications world. The 6th WebRTC Summit continues our tradition of delivering the latest and greatest presentations within the world of WebRTC. Topics include voice calling, video chat, P2P file sharing, and use cases that have already leveraged the power and convenience of WebRTC.
Unsecured IoT devices were used to launch crippling DDOS attacks in October 2016, targeting services such as Twitter, Spotify, and GitHub. Subsequent testimony to Congress about potential attacks on office buildings, schools, and hospitals raised the possibility for the IoT to harm and even kill people. What should be done? Does the government need to intervene? This panel at @ThingExpo New York brings together leading IoT and security experts to discuss this very serious topic.
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
An IoT product’s log files speak volumes about what’s happening with your products in the field, pinpointing current and potential issues, and enabling you to predict failures and save millions of dollars in inventory. But until recently, no one knew how to listen. In his session at @ThingsExpo, Dan Gettens, Chief Research Officer at OnProcess, discussed recent research by Massachusetts Institute of Technology and OnProcess Technology, where MIT created a new, breakthrough analytics model for ...
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
More and more brands have jumped on the IoT bandwagon. We have an excess of wearables – activity trackers, smartwatches, smart glasses and sneakers, and more that track seemingly endless datapoints. However, most consumers have no idea what “IoT” means. Creating more wearables that track data shouldn't be the aim of brands; delivering meaningful, tangible relevance to their users should be. We're in a period in which the IoT pendulum is still swinging. Initially, it swung toward "smart for smar...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
"We build IoT infrastructure products - when you have to integrate different devices, different systems and cloud you have to build an application to do that but we eliminate the need to build an application. Our products can integrate any device, any system, any cloud regardless of protocol," explained Peter Jung, Chief Product Officer at Pulzze Systems, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Internet of @ThingsExpo has announced today that Chris Matthieu has been named tech chair of Internet of @ThingsExpo 2017 New York The 7th Internet of @ThingsExpo will take place on June 6-8, 2017, at the Javits Center in New York City, New York. Chris Matthieu is the co-founder and CTO of Octoblu, a revolutionary real-time IoT platform recently acquired by Citrix. Octoblu connects things, systems, people and clouds to a global mesh network allowing users to automate and control design flo...
In addition to all the benefits, IoT is also bringing new kind of customer experience challenges - cars that unlock themselves, thermostats turning houses into saunas and baby video monitors broadcasting over the internet. This list can only increase because while IoT services should be intuitive and simple to use, the delivery ecosystem is a myriad of potential problems as IoT explodes complexity. So finding a performance issue is like finding the proverbial needle in the haystack.