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Standard Performance Evaluation Corporation

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Klaus-Dieter Lange, SPECpower chair,
on measuring server efficiency

Klaus-Dieter Lange is the founding chair of the Standard Performance Evaluation Corporation's SPECpower committee, a consortium of leading industry vendors, researchers and scientists committed to developing and implementing new standards for measuring server efficiency.

The latest product from the SPECpower committee is version 2 of the Server Efficiency Rating Tool (SERT) suite, which rates energy efficiency of single- and multi-node servers across a broad span of configurations.

In this interview, Lange discusses the origin of SERT, the challenges of creating an international standard, the prospect of continued improvements in server efficiency, and his own personal growth in leading a diverse group of technologists.

The SPECpower committee started developing SERT about five years ago. Why did you think this type of standard was needed?

At that time, the SPECpower committee had been working already for about six years to develop standards for reporting system power usage for servers. In December 2007, we released SPECpower_ssj2008, the first industry-standard benchmark that measures power consumption in relation to performance for server-class computers. Government agencies, especially the U.S. Environmental Protection Agency (EPA), were interested in using the benchmark. But SPECpower_ssj2008 covers only one specific type of workload; we realized the EPA needed a tool that would cover a much wider spectrum.

We advised the EPA that SPECpower_ssj2008 was probably not the best thing to use for regulatory purposes and we offered to develop a tool that would be really useful for regulatory agencies.

The challenge with SERT is that you have to address the entire server configuration spectrum: As an industry-standard regulatory tool, it has to cover everything from the entry-level system to the state-of-the-art system that would exist three to five years in the future.

SERT testing is a mandatory part of the U.S. EPA's ENERGY STAR for Computer Servers specification and it's under consideration by other international agencies. What is SPEC doing to make SERT a worldwide standard?

After the EPA adopted SERT, other agencies around the world started to reach out to us, saying that they heard we had something and they might want to utilize it. We have responded to specific requests by traveling to different countries to present the program and allow agencies to see and work with it in a hands-on way. In 2016, we held server efficiency symposiums in the United States, Europe and China.

SERT is being considered by the European Union's DG ENTR Lot 9 Ecodesign Directive for enterprise servers, the Chinese National Institute of Standardization (CNIS), and Japan's Ministry of Economy, Trade & Industry's (METI) Top Runner energy efficiency program. We seek input from these and other regulatory agencies globally to ensure that SERT will fit their needs.

What are the challenges you face in trying to establish SERT as an international standard?

Obviously, language is a major one. We've translated the SERT user guide, for example, into Chinese for the vast number of potential users in that market. We also have to work across different cultures, political systems, regulations, and decision-making processes that are sometimes quite different in various regions.

What are the advantages for standards bodies from different regions across the globe to adopt SERT?

SERT has been in continuous development and testing for five years, or more than a decade if you count the research and development that has gone into SPECpower_ssj2008. It has been on the market as a product for four years and its metric is fully established. Many different organizations in addition to SPEC have validated SERT and ascertained that it has a high degree of relevance to their server energy programs.

The basic value of SERT is that it is one holistic tool that can be used in a wide variety of computing and social environments to rate server efficiency and therefore reduce the cost of testing. This allows vendors, agencies and users to concentrate resources on the most important thing: improving server efficiency.

Why is SPEC a good organization to develop a standard such as SERT?

You could not create SERT within one company; so an industry consortium like SPEC is really necessary, providing the foundation for this kind of incubator of new ideas.

One of the core attributes of SPEC is that we have a very diverse representation of industry specialists -- CPU, storage, networking, software, hardware, power measurement -- who have an incredible amount of experience in developing fair and consistent standards for measuring performance and power. We also have a wide geographical distribution of members who have experience with regional and international standards agencies.

Then there are the philosophy and operating procedures ingrained in SPEC that encourage cooperation and fairness among diverse and competitive organizations. Decisions are made by consensus and based on reality, where experimental results carry more weight than opinion. Data and demonstration overrule assertion. And, tools and benchmarks must always be architecture-neutral and portable across computing platforms.

Do you need to get different people involved in developing a tool such as SERT compared to developing a benchmark?

You need a more diverse team of people -- researchers, visionaries, programmers, tech writers, QA experts, program leaders, etc. You need the people who are familiar with different regions and can connect with the government agencies in those regions.

The development process needs to be more open to accommodate government involvement. There's much more sharing of data and input from a wider variety of organizations.

You have to step up your development and testing efforts to take into consideration a lot of different usage patterns and system configurations.

SERT 2.0 was released on March 28, 2017. What are the most important aspects of this new release?

There are three major developments in SERT 2.0 that will benefit vendors, users and agencies.

The major item is the single SERT metric, something agencies really needed. We worked with the SPEC RG Power Working Group to take into consideration all the data points that are measured with SERT and create a single metric that is easy to understand and applicable across multiple platforms.

Secondly, we requested and received a lot of customer feedback leading up to this release and incorporated many improvements under the hood in areas like usability, automation and support of new platforms and power measurement devices.

Thirdly, we've reduced the run time from about four-and-a-half hours to about two. This helps customers do more testing during the course of a day and to generate much more data to analyze and improve upon.


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SERT is built on the experience gained in developing the SPECpower_ssj2008 benchmark, for which scores posted on the SPEC website have increased by more than 17 times over the last nine years. Do you think those kind of improvements are sustainable?

It's a tricky question, and different companies would likely give you different answers. I've been working on server design for the last 20 years and the industry is constantly evolving, improving current technologies and introducing new ones to further improve server efficiency.

We're continuing to see that users can do more with less power and vendors are achieving higher efficiency at every power level -- from peak, to midrange, down to idle. In storage, for example, you might have similar power values over time but you will have much more storage capacity for those values.

SERT is developed with that in mind, as the design of each SERT worklet is architecture-agnostic, and will support downloadable updates for future platform support.

The other thing to consider is energy improvement in the data centers themselves -- not just the server, but the entire environment -- tooling, insulation, cooling and things like power capping. The overall data center environment is something that will need to be addressed by future energy measurement tools.

How has your experience with SPECpower contributed to your personal growth?

I'm very grateful I've had the opportunity to serve as SPECpower chair for the last decade; it has enabled my personal effectiveness to grow quite a bit. You have to learn to lead a diverse team, with people from different companies, different cultural backgrounds, different languages, and different geographical areas. I've learned a lot from leading those experts with expertise in many diverse areas.

Probably the most important thing I've learned is that you cannot make everybody happy. So my goal as chairman is to make everybody equally unhappy in order to ensure that no company has an unfair advantage.