SC13 Research Highlight: COCA Targets Datacenter Costs, Carbon Neutrality

By Shaolei Ren and Yuxiong He

November 16, 2013

The rapid growth of high performance computing and cloud computing services in recent years has contributed to the dramatic increase in the number and scale of data centers, resulting in a huge demand for electricity.

According to recent studies, the combined electricity consumption of global data centers amounts to 623 billion kWh annually and would rank 5th in the world if the data center were a country. As a significant portion of electricity is produced by coal or other carbon-intensive sources, it is often labeled as “brown energy” and the growing trend of the data center electricity consumption has raised serious concerns about its carbon footprint as well as environmental impacts, such as altering global patterns of temperature, rainfall, and creation of drought and flood.

Recently, large data center operators such as Google and Microsoft have been increasingly urged to find effective solutions to reduce their carbon emissions for sustainable computing and ultimately achieve an overall net-zero carbon footprint (i.e., carbon neutrality), as mandated by governments in the form of Kyoto-style protocols, voluntarily for public images, or urged by environmental organizations.

While it is beneficial for sustainability, achieving carbon neutrality presents significant challenges for data center operators, because the best location for building a data center may not be the most desired location for generating sufficient green energies (e.g., solar, wind) to satisfy the data center requirement and using carbon-free electricity directly from utility companies is not yet widely available. Thus, as a practical alternative, carbon-neutral data centers often rely on a bundle of approaches, such as generating off-site green (or renewable) energy and purchasing renewable energy credits (RECs): using renewable energy to indirectly offset electricity usage.

Completely offsetting electricity usage via off-site renewable energy generation for long-term carbon neutrality is desirable yet challenging: data centers need to carefully budget electricity usage over a long timescale (often a year) such that the “unknown” future brown energy consumption can be completely offset by limited renewables. While it seems to be easy to plan the electricity usage over a long timescale based on the future computing demand, a practical challenge is that the far future time-varying workloads or intermittent renewable energy availability cannot be accurately predicted and hence data centers need to decide electricity usage in an online manner.

In our research, we study long-term energy budgeting for a carbon-neutral data center and propose a provably-efficient online resource management algorithm, called COCA (optimizing for COst minimization and CArbon neutrality), for minimizing the operational cost while satisfying carbon neutrality without requiring long-term future information. Both electricity cost and delay performance are incorporated into our optimization objective.

COCA eliminates the requirement of knowing long-term future computing demand information by keeping track of the “carbon deficit” online. As the name implies, carbon deficit indicates how far the current data center operation deviates from carbon neutrality, or more precisely, how much the current electricity usage has exceeded the available renewables. Incorporating the carbon deficit into the optimization objective, COCA progressively adheres to carbon neutrality by adapting the weight of electricity consumption. Specifically, if the carbon deficit is larger, COCA will place more emphasis on reducing electricity consumption by turning down more servers such that the carbon deficit can be offset by future renewables. Thus, COCA works following the philosophy of “if violating carbon neutrality, then use less electricity”.  While the intuition is straightforward, we formally prove by extending the recently-developed Lyapunov optimization that COCA achieves a close-to-minimum operational cost, compared to the optimal offline algorithm with look-ahead information, while bounding the maximum possible carbon deficit.

Large data centers often consist of up to tens of thousands of servers, and distributed server management is highly desirable for scalability. Towards this end, we embed distributed resource management in COCA such that each server autonomously adjusts its processing speed (and hence, power consumption, too) and optimally decides the amount of workloads to process. Specifically, each server can “learn” the optimal decision by sampling a set of possible decisions and eventually choosing the best one with very high probability.

To validate COCA, we perform an extensive simulation study modeling the one-year operation of a large data center. Using real-world production traces to drive the simulation, we first compare COCA against state-of-the-art prediction-based method in terms of the average hourly operational cost. In particular, PerfectHP (Perfect Hourly Prediction heuristic), which perfectly predicts 48-hour-ahead workloads and allocates the carbon budget in proportion to the hourly workloads, is chosen as the benchmark. As shown in the figure, COCA is more cost effective compared to PerfectHP with a cost saving of more than 25% over one year. COCA achieves the benefit because even though the workload spikes and carbon neutrality is temporarily violated, it can focus on cost minimization while carbon deficit will then later guide the data center operation towards carbon neutrality. By contrast, without foreseeing the long-term future, short-term prediction-based PerfectHP may over-allocate the carbon budget at inappropriate time slots and thus have to set a stringent budget for certain time slots when the workload is high.


Next, we show that, under different electricity usage budgets, the operational cost of COCA is always fairly close to the minimum value achieved by the optimal offline algorithm with complete future information. Operational cost and electricity usage are normalized with respect to the carbon-unaware algorithm that disregards carbon neutrality and purely minimizes the operational cost. It can be seen that with a normalized electricity usage of 0.9 (i.e., saving 10% electricity usage compared to the carbon-unaware algorithm), COCA only increases the operational cost by less than 3% compared to both the carbon-unaware algorithm and the optimal offline algorithm that has the complete future information. This demonstrates a strong applicability of COCA in real systems due to its good performance and online execution without complete offline information.


To summarize, COCA addresses carbon neutrality, an emerging issue in data centers: it enables data centers to achieve a low operational cost while satisfying carbon neutrality in the absence of long-term future information. The distinguishing feature of online and distributed implementation makes COCA an appealing candidate for autonomously managing computing resources in large data centers.

SESSION: Performance Management of HPC Systems


TIME: Tuesday, 11:30AM – 12:00PM

ROOM: 401/402/403

Shaolei Ren received his Ph.D. from University of California, Los Angeles, in 2012 and is currently with Florida International University as an Assistant Professor. His research focuses on sustainability and emerging topics in cloud computing such as water usage effectiveness.

Yuxiong He is a researcher at Microsoft Research.  Her research interests include resource management, algorithms, modeling and performance evaluation of parallel and distributed systems.  Her recent work focuses on improving responsiveness, quality and throughput of large-scale interactive cloud services such as web search.  Yuxiong received her Ph.D. in Computer Science from Singapore-MIT Alliance in 2008.

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

European HPC Summit Week and PRACEdays 2018: Slaying Dragons and SHAPEing Futures One SME at a Time

June 20, 2018

The University of Ljubljana in Slovenia hosted the third annual EHPCSW18 and fifth annual PRACEdays18 events which opened May 29, 2018. The conference was chaired by PRACE Council Vice-Chair Sergi Girona (Barcelona Super Read more…

By Elizabeth Leake (STEM-Trek for HPCwire)

An Overview of ‘OpenACC for Programmers’ from the Book’s Editors

June 20, 2018

In an era of multicore processors coupled with manycore accelerators in all kinds of devices from smartphones all the way to supercomputers, it is important to train current and future computational scientists of all dom Read more…

By Sunita Chandrasekaran and Guido Juckeland

Cray Introduces All Flash Lustre Storage Solution Targeting HPC

June 19, 2018

Citing the rise of IOPS-intensive workflows and more affordable flash technology, Cray today introduced the L300F, a scalable all-flash storage solution whose primary use case is to support high IOPS rates to/from a scra Read more…

By John Russell

HPE Extreme Performance Solutions

HPC and AI Convergence is Accelerating New Levels of Intelligence

Data analytics is the most valuable tool in the digital marketplace – so much so that organizations are employing high performance computing (HPC) capabilities to rapidly collect, share, and analyze endless streams of data. Read more…

IBM Accelerated Insights

Preview the World’s Smartest Supercomputer at ISC 2018

Introducing an accelerated IT infrastructure for HPC & AI workloads Read more…

Lenovo to Debut ‘Neptune’ Cooling Technologies at ISC

June 19, 2018

Lenovo today announced a set of cooling technologies, dubbed Neptune, that include direct to node (DTN) warm water cooling, rear door heat exchanger (RDHX), and hybrid solutions that combine air and liquid cooling. Lenov Read more…

By John Russell

European HPC Summit Week and PRACEdays 2018: Slaying Dragons and SHAPEing Futures One SME at a Time

June 20, 2018

The University of Ljubljana in Slovenia hosted the third annual EHPCSW18 and fifth annual PRACEdays18 events which opened May 29, 2018. The conference was chair Read more…

By Elizabeth Leake (STEM-Trek for HPCwire)

Cray Introduces All Flash Lustre Storage Solution Targeting HPC

June 19, 2018

Citing the rise of IOPS-intensive workflows and more affordable flash technology, Cray today introduced the L300F, a scalable all-flash storage solution whose p Read more…

By John Russell

Sandia to Take Delivery of World’s Largest Arm System

June 18, 2018

While the enterprise remains circumspect on prospects for Arm servers in the datacenter, the leadership HPC community is taking a bolder, brighter view of the x86 server CPU alternative. Amongst current and planned Arm HPC installations – i.e., the innovative Mont-Blanc project, led by Bull/Atos, the 'Isambard’ Cray XC50 going into the University of Bristol, and commitments from both Japan and France among others -- HPE is announcing that it will be supply the United States National Nuclear Security Administration (NNSA) with a 2.3 petaflops peak Arm-based system, named Astra. Read more…

By Tiffany Trader

The Machine Learning Hype Cycle and HPC

June 14, 2018

Like many other HPC professionals I’m following the hype cycle around machine learning/deep learning with interest. I subscribe to the view that we’re probably approaching the ‘peak of inflated expectation’ but not quite yet starting the descent into the ‘trough of disillusionment. This still raises the probability that... Read more…

By Dairsie Latimer

Xiaoxiang Zhu Receives the 2018 PRACE Ada Lovelace Award for HPC

June 13, 2018

Xiaoxiang Zhu, who works for the German Aerospace Center (DLR) and Technical University of Munich (TUM), was awarded the 2018 PRACE Ada Lovelace Award for HPC for her outstanding contributions in the field of high performance computing (HPC) in Europe. Read more…

By Elizabeth Leake

U.S Considering Launch of National Quantum Initiative

June 11, 2018

Sometime this month the U.S. House Science Committee will introduce legislation to launch a 10-year National Quantum Initiative, according to a recent report by Read more…

By John Russell

ORNL Summit Supercomputer Is Officially Here

June 8, 2018

Oak Ridge National Laboratory (ORNL) together with IBM and Nvidia celebrated the official unveiling of the Department of Energy (DOE) Summit supercomputer toda Read more…

By Tiffany Trader

Exascale USA – Continuing to Move Forward

June 6, 2018

The end of May 2018, saw several important events that continue to advance the Department of Energy’s (DOE) Exascale Computing Initiative (ECI) for the United Read more…

By Alex R. Larzelere

MLPerf – Will New Machine Learning Benchmark Help Propel AI Forward?

May 2, 2018

Let the AI benchmarking wars begin. Today, a diverse group from academia and industry – Google, Baidu, Intel, AMD, Harvard, and Stanford among them – releas Read more…

By John Russell

How the Cloud Is Falling Short for HPC

March 15, 2018

The last couple of years have seen cloud computing gradually build some legitimacy within the HPC world, but still the HPC industry lies far behind enterprise I Read more…

By Chris Downing

US Plans $1.8 Billion Spend on DOE Exascale Supercomputing

April 11, 2018

On Monday, the United States Department of Energy announced its intention to procure up to three exascale supercomputers at a cost of up to $1.8 billion with th Read more…

By Tiffany Trader

Deep Learning at 15 PFlops Enables Training for Extreme Weather Identification at Scale

March 19, 2018

Petaflop per second deep learning training performance on the NERSC (National Energy Research Scientific Computing Center) Cori supercomputer has given climate Read more…

By Rob Farber

Lenovo Unveils Warm Water Cooled ThinkSystem SD650 in Rampup to LRZ Install

February 22, 2018

This week Lenovo took the wraps off the ThinkSystem SD650 high-density server with third-generation direct water cooling technology developed in tandem with par Read more…

By Tiffany Trader

ORNL Summit Supercomputer Is Officially Here

June 8, 2018

Oak Ridge National Laboratory (ORNL) together with IBM and Nvidia celebrated the official unveiling of the Department of Energy (DOE) Summit supercomputer toda Read more…

By Tiffany Trader

Nvidia Responds to Google TPU Benchmarking

April 10, 2017

Nvidia highlights strengths of its newest GPU silicon in response to Google's report on the performance and energy advantages of its custom tensor processor. Read more…

By Tiffany Trader

Hennessy & Patterson: A New Golden Age for Computer Architecture

April 17, 2018

On Monday June 4, 2018, 2017 A.M. Turing Award Winners John L. Hennessy and David A. Patterson will deliver the Turing Lecture at the 45th International Sympo Read more…

By Staff

Leading Solution Providers

SC17 Booth Video Tours Playlist

Altair @ SC17


AMD @ SC17


ASRock Rack @ SC17

ASRock Rack



DDN Storage @ SC17

DDN Storage

Huawei @ SC17


IBM @ SC17


IBM Power Systems @ SC17

IBM Power Systems

Intel @ SC17


Lenovo @ SC17


Mellanox Technologies @ SC17

Mellanox Technologies

Microsoft @ SC17


Penguin Computing @ SC17

Penguin Computing

Pure Storage @ SC17

Pure Storage

Supericro @ SC17


Tyan @ SC17


Univa @ SC17


Google Chases Quantum Supremacy with 72-Qubit Processor

March 7, 2018

Google pulled ahead of the pack this week in the race toward "quantum supremacy," with the introduction of a new 72-qubit quantum processor called Bristlecone. Read more…

By Tiffany Trader

Google I/O 2018: AI Everywhere; TPU 3.0 Delivers 100+ Petaflops but Requires Liquid Cooling

May 9, 2018

All things AI dominated discussion at yesterday’s opening of Google’s I/O 2018 developers meeting covering much of Google's near-term product roadmap. The e Read more…

By John Russell

Nvidia Ups Hardware Game with 16-GPU DGX-2 Server and 18-Port NVSwitch

March 27, 2018

Nvidia unveiled a raft of new products from its annual technology conference in San Jose today, and despite not offering up a new chip architecture, there were still a few surprises in store for HPC hardware aficionados. Read more…

By Tiffany Trader

Pattern Computer – Startup Claims Breakthrough in ‘Pattern Discovery’ Technology

May 23, 2018

If it weren’t for the heavy-hitter technology team behind start-up Pattern Computer, which emerged from stealth today in a live-streamed event from San Franci Read more…

By John Russell

Part One: Deep Dive into 2018 Trends in Life Sciences HPC

March 1, 2018

Life sciences is an interesting lens through which to see HPC. It is perhaps not an obvious choice, given life sciences’ relative newness as a heavy user of H Read more…

By John Russell

Intel Pledges First Commercial Nervana Product ‘Spring Crest’ in 2019

May 24, 2018

At its AI developer conference in San Francisco yesterday, Intel embraced a holistic approach to AI and showed off a broad AI portfolio that includes Xeon processors, Movidius technologies, FPGAs and Intel’s Nervana Neural Network Processors (NNPs), based on the technology it acquired in 2016. Read more…

By Tiffany Trader

Google Charts Two-Dimensional Quantum Course

April 26, 2018

Quantum error correction, essential for achieving universal fault-tolerant quantum computation, is one of the main challenges of the quantum computing field and it’s top of mind for Google’s John Martinis. At a presentation last week at the HPC User Forum in Tucson, Martinis, one of the world's foremost experts in quantum computing, emphasized... Read more…

By Tiffany Trader

Cray Rolls Out AMD-Based CS500; More to Follow?

April 18, 2018

Cray was the latest OEM to bring AMD back into the fold with introduction today of a CS500 option based on AMD’s Epyc processor line. The move follows Cray’ Read more…

By John Russell

  • arrow
  • Click Here for More Headlines
  • arrow
Do NOT follow this link or you will be banned from the site!
Share This