Welcome!

Linux Containers Authors: Pat Romanski, Elizabeth White, Liz McMillan, Vaibhaw Pandey, Yeshim Deniz

Related Topics: Linux Containers

Linux Containers: Article

Preparing for the Revolution

Dual-core technology for HPC Clusters

MPI (Message Passing Interface)
In the high-performance computing market, parallelism is often expressed using the MPI programming interface. In contrast to threaded approaches, MPI uses messages to copy memory from one process space (program) to another. This approach is very effective when the processors don't share local memory (e.g., they're located on another motherboard in the HPC cluster). It can be used, however, for multi-core programming as well. And there are many programs that have already been ported to MPI that can take advantage of multiple-cores without any re-programming.

In our cash register analogy the "MPI cashier:" would call other stores on the phone and tick off the items in the shopping cart that they have to tabulate. The advantage here is that the size (scale) of the order can get very big and exceed the capacity of the cash registers of any one store (computer). MPI is available as a library for most languages (C/C++ and Fortran) and is available in both commercial and Open Source packages. For Linux HPC clusters, hybrid methods that employ both OpenMP (intra-motherboard communication) and MPI (inter-motherboard communication) are now being studied.

Debugging Methods
There's an old joke that goes "Every program works just fine, getting it to work the way you want it to is the trick." Parallel programs like their sequential program cousins are no exception. In fact, parallel programs represent a much harder proposition because unlike serial programs there's the notion of synchronization and data sharing. These properties can make it hard to fully understand program behavior in a real-world environment where program execution may not be easily replicated.

The choice of debugger can be critical to the success of any multi-core programming project. Without the ability to see what the program is doing in real-time, multi-core applications can be impossible to develop in any meaningful timeframe.

Recommendations
The multi-core revolution forces software developers to evaluate their codes in terms of multi-core performance now and as the cores increases in the future. In particular, many Linux HPC clusters can easily see a doubling of CPU cores simply by upgrading the processor. The following recommendations are designed to help aid in the transition to multi-core architectures:

  • Assess the level of concurrency in your application: Concurrency isn't present (or necessary) in all applications. Some applications, by virtue of their algorithms, can only be executed in a serial fashion. Examining the algorithm is the only effective way to access of the presence of concurrency in your application. Careful attention to memory access patterns by various parts of the program is important since dependencies will inhibit the ability to operate concurrently.
  • Assess, if possible, whether concurrency will improve performance: If you can identify concurrent parts of your application, look carefully to see if executing them in parallel will result in application speed-up (reduced execution time). There are often parts of your program that could be executed concurrently, but have no effect on execution time. There's no point in spending time on these sections of code. Typically you should focus your attention on the computationally heavy parts of your application.
  • Assess the scalability of your applications: Another important question to ask is how scalable your application is. As more processors are added, parallel execution will always hit the point of diminishing returns. This means that creating more threads won't improve performance (it may actually hurt performance). If you find that your application can be scaled to a large number of processors then using MPI may be a good choice. If, however, you don't envision using more than four processors then pthreads or OpenMP is probably your best choices.
  • Make sure there's an adequate tool chain for your application: This last recommendation is critical to the your application's success. There are many ways of using multiple processors, but not all of them have tool chains that provide the professional support and capabilities needed to produce software in a reasonable period of time and at a reasonable cost. Research projects should be avoided and the use of mainstream compilers, debugger, and profiles should be a high priority.
Conclusion
Taking advantage of multi-core technologies is the next step in software development and HPC cluster performance. Once a plan and infrastructure are in place the benefits of dual-core processors can be realized by customers and users alike. A commitment to parallel computing will provide solid and sustained performance growth into the future.

References
These sources can be consulted for general information about multi-core hardware and software.

Hardware

Programming Issues pthreads OpenMP MPI
  • Using MPI - 2nd Edition: Portable Parallel Programming with the Message Passing Interface, William Gropp, Ewing Lusk, Anthony Skjellum, ISBN: 0262571323
  • MPI Web site: www-unix.mcs.anl.gov/mpi/

More Stories By Douglas Eadline

Dr. Douglas Eadline has over 25 years of experience in high-performance computing. You can contact him through Basement Supercomputing (http://basement-supercomputing.com).

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
"Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that Conference Guru has been named “Media Sponsor” of the 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. A valuable conference experience generates new contacts, sales leads, potential strategic partners and potential investors; helps gather competitive intelligence and even provides inspiration for new products and services. Conference Guru works with conference organizers to pass great deals to gre...
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 develop...
In his Opening Keynote at 21st Cloud Expo, John Considine, General Manager of IBM Cloud Infrastructure, led attendees through the exciting evolution of the cloud. He looked at this major disruption from the perspective of technology, business models, and what this means for enterprises of all sizes. John Considine is General Manager of Cloud Infrastructure Services at IBM. In that role he is responsible for leading IBM’s public cloud infrastructure including strategy, development, and offering m...
"Evatronix provides design services to companies that need to integrate the IoT technology in their products but they don't necessarily have the expertise, knowledge and design team to do so," explained Adam Morawiec, VP of Business Development at Evatronix, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
Large industrial manufacturing organizations are adopting the agile principles of cloud software companies. The industrial manufacturing development process has not scaled over time. Now that design CAD teams are geographically distributed, centralizing their work is key. With large multi-gigabyte projects, outdated tools have stifled industrial team agility, time-to-market milestones, and impacted P&L stakeholders.
"Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
"IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
22nd International Cloud Expo, taking place June 5-7, 2018, at the Javits Center in New York City, NY, and co-located with the 1st DXWorld Expo 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 ...
"Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
"MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
"There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
It is of utmost importance for the future success of WebRTC to ensure that interoperability is operational between web browsers and any WebRTC-compliant client. To be guaranteed as operational and effective, interoperability must be tested extensively by establishing WebRTC data and media connections between different web browsers running on different devices and operating systems. In his session at WebRTC Summit at @ThingsExpo, Dr. Alex Gouaillard, CEO and Founder of CoSMo Software, presented ...