Welcome!

Websphere Authors: Pat Romanski, Carmen Gonzalez, Yeshim Deniz, Elizabeth White, Sanjeev Sharma

Related Topics: Websphere

Websphere: 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
The 3rd International Internet of @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
An entirely new security model is needed for the Internet of Things, or is it? Can we save some old and tested controls for this new and different environment? In his session at @ThingsExpo, New York's at the Javits Center, Davi Ottenheimer, EMC Senior Director of Trust, reviewed hands-on lessons with IoT devices and reveal a new risk balance you might not expect. Davi Ottenheimer, EMC Senior Director of Trust, has more than nineteen years' experience managing global security operations and assessments, including a decade of leading incident response and digital forensics. He is co-author of t...
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges. In his session at @ThingsExpo, Jeff Kaplan, Managing Director of THINKstrategies, will examine why IT must finally fulfill its role in support of its SBUs or face a new round of...
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, described an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device experiences grounded in people's real needs and desires.
Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps, abiding by privacy concerns and making the concept a reality. These challenges can't be addressed w...
The Domain Name Service (DNS) is one of the most important components in networking infrastructure, enabling users and services to access applications by translating URLs (names) into IP addresses (numbers). Because every icon and URL and all embedded content on a website requires a DNS lookup loading complex sites necessitates hundreds of DNS queries. In addition, as more internet-enabled ‘Things' get connected, people will rely on DNS to name and find their fridges, toasters and toilets. According to a recent IDG Research Services Survey this rate of traffic will only grow. What's driving t...
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, examined three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics is e...
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
We are reaching the end of the beginning with WebRTC, and real systems using this technology have begun to appear. One challenge that faces every WebRTC deployment (in some form or another) is identity management. For example, if you have an existing service – possibly built on a variety of different PaaS/SaaS offerings – and you want to add real-time communications you are faced with a challenge relating to user management, authentication, authorization, and validation. Service providers will want to use their existing identities, but these will have credentials already that are (hopefully) i...
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it's a mix of architectural styles ...
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water, are pursuing SmartGrid initiatives that represent one of the more mature examples of SAE. We have s...
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at @ThingsExpo, Robin Raymond, Chief Architect at Hookflash, will walk through the shifting landscape of traditional telephone and voice services ...
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example t...
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Architect for the Internet of Things and Intelligent Systems at Red Hat, described how to revolutioniz...
Bit6 today issued a challenge to the technology community implementing Web Real Time Communication (WebRTC). To leap beyond WebRTC’s significant limitations and fully leverage its underlying value to accelerate innovation, application developers need to consider the entire communications ecosystem.
The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from hardware to software, or as we like to say, it’s an Internet of many different things. The difference ...
Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, phone and digital TV services to consumers primarily in rural areas.