For Energy-Efficient HPC, Less is More

By Ian Armas Foster

September 19, 2012

Near-Threshold Voltage, or NTV, has the potential to significantly cut energy requirements for high performance computing. This is becoming especially important for the largest supercomputers, which are already well into the multi-megawatt realm and are expected to hit tens of megawatts in the exascale era.

Intel recently demonstrated their NTV capabilities at ISSCC 2012, operating an x86 microprocessor on only 2 milliWatts of power. The company published three papers on their results, which were analyzed and discussed in an article at Real World Technologies by David Kanter.

The threshold voltage is the voltage required to generate a minimum of current across a transistor. Intel has discovered that the most efficient use of energy would be to operate a circuit near that of its threshold voltage, that is, the amount required to turn a transistor on.

There are a couple of intrinsically tricky things about operating at such a low voltage. The first is limiting dI/dt, the fancy mathematical way of expressing change in current over time. Rapid spikes or drops in current, especially those that would occur as a result of a particular transistor accidentally dropping beneath the threshold, can create computational errors.

Ideally, all transistors would be created equally. Statistically, however, since there sometimes lie billions of transistors on a given chip, some will perform worse that others.

Another challenge to overcome is the resulting power loss. The power available is proportional to the square of the voltage, such that a 10 percent reduction in voltage leads to a 19 percent reduction in power. While this reduced voltage would be a great way to increase efficiency, it would also be a great way to ensure your CPU does not have the juice required to run what it needs to.

Further, NTV significantly decreases frequency. “The 32nm Pentium core,” Kanter said about a core that ran using NTV “increased efficiency by about 5×, by running at slightly under 100MHz. The maximum frequency was 915MHz, so the absolute performance decreased by about an order of magnitude.”

As he notes, NTV would be impractical for general-purpose CPUs, as they are generally used for applications that expect reasonable single-threaded performance. Thus they require the higher voltages needed to drive faster clocks. On the other hand, HPC and its massively parallel computing environment could benefit greatly from NTV.

“Based on our analysis of these papers,” Kanter wrote, “Near-Threshold Voltage computing techniques are most applicable to highly parallel workloads. Generally, NTV is an ideal fit for HPC workloads and works very well for graphics, but not general purpose CPUs.”

Since HPC is highly parallelized and requires backups and fail-safe mechanisms throughout a computation, it can withstand the consequences of a single transistor giving out. HPC computations are also not expected to happen anywhere near real time, making the frequency decrease less of a problem. This is especially true of “throughput” accelerators like GPGPUs and Intel’s Xeon Phi, which are naturally frequency-constrained because of their high core counts.

There is a sense that this technology is being developed to specifically benefit HPC rather than it accidentally doing so. This is not only hinted at by the Intel papers themselves, but is also indirectly supported by the people funding the papers, specifically the US Government. “Perhaps most telling,” Kanter wrote, “US government grants typically focus on areas of national interest. Graphics simply is not vital to the country, whereas HPC is a critical tool for the Departments of Defense, Energy, and any number of intelligence agencies.”

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!

InfiniBand Still Tops in Supercomputing

July 19, 2018

In the competitive global HPC landscape, system and processor vendors, nations and end user sites certainly get a lot of attention--deservedly so--but more than ever, the network plays a crucial role. While fast, perform Read more…

By Tiffany Trader

HPC for Life: Genomics, Brain Research, and Beyond

July 19, 2018

During the past few decades, the life sciences have witnessed one landmark discovery after another with the aid of HPC, paving the way toward a new era of personalized treatments based on an individual’s genetic makeup Read more…

By Warren Froelich

WCRP’s New Strategic Plan for Climate Research Highlights the Importance of HPC

July 19, 2018

As climate modeling increasingly leverages exascale computing and researchers warn of an impending computing gap in climate research, the World Climate Research Programme (WCRP) is developing its new Strategic Plan – and high-performance computing is slated to play a critical role. Read more…

By Oliver Peckham

HPE Extreme Performance Solutions

Introducing the First Integrated System Management Software for HPC Clusters from HPE

How do you manage your complex, growing cluster environments? Answer that big challenge with the new HPC cluster management solution: HPE Performance Cluster Manager. Read more…

IBM Accelerated Insights

Are Your Software Licenses Impeding Your Productivity?

In my previous article, Improving chip yield rates with cognitive manufacturing, I highlighted the costs associated with semiconductor manufacturing, and how cognitive methods can yield benefits in both design and manufacture.  Read more…

U.S. Exascale Computing Project Releases Software Technology Progress Report

July 19, 2018

As is often noted the race to exascale computing isn’t just about hardware. This week the U.S. Exascale Computing Project (ECP) released its latest Software Technology (ST) Capability Assessment Report detailing progress so far. Read more…

By John Russell

InfiniBand Still Tops in Supercomputing

July 19, 2018

In the competitive global HPC landscape, system and processor vendors, nations and end user sites certainly get a lot of attention--deservedly so--but more than Read more…

By Tiffany Trader

HPC for Life: Genomics, Brain Research, and Beyond

July 19, 2018

During the past few decades, the life sciences have witnessed one landmark discovery after another with the aid of HPC, paving the way toward a new era of perso Read more…

By Warren Froelich

D-Wave Breaks New Ground in Quantum Simulation

July 16, 2018

Last Friday D-Wave scientists and colleagues published work in Science which they say represents the first fulfillment of Richard Feynman’s 1982 notion that Read more…

By John Russell

AI Thought Leaders on Capitol Hill

July 14, 2018

On Thursday, July 12, the House Committee on Science, Space, and Technology heard from four academic and industry leaders – representatives from Berkeley Lab, Argonne Lab, GE Global Research and Carnegie Mellon University – on the opportunities springing from the intersection of machine learning and advanced-scale computing. Read more…

By Tiffany Trader

HPC Serves as a ‘Rosetta Stone’ for the Information Age

July 12, 2018

In an age defined and transformed by its data, several large-scale scientific instruments around the globe might be viewed as a ‘mother lode’ of precious data. With names seemingly created for a ‘techno-speak’ glossary, these interferometers, cyclotrons, sequencers, solenoids, satellite altimeters, and cryo-electron microscopes are churning out data in previously unthinkable and seemingly incomprehensible quantities -- billions, trillions and quadrillions of bits and bytes of electro-magnetic code. Read more…

By Warren Froelich

Tsinghua Powers Through ISC18 Field

July 10, 2018

Tsinghua University topped all other competitors at the ISC18 Student Cluster Competition with an overall score of 88.43 out of 100. This gives Tsinghua their s Read more…

By Dan Olds

HPE, EPFL Launch Blue Brain 5 Supercomputer

July 10, 2018

HPE and the Ecole Polytechnique Federale de Lausannne (EPFL) Blue Brain Project yesterday introduced Blue Brain 5, a new supercomputer built by HPE, which displ Read more…

By John Russell

Pumping New Life into HPC Clusters, the Case for Liquid Cooling

July 10, 2018

High Performance Computing (HPC) faces some daunting challenges in the coming years as traditional, industry-standard systems push the boundaries of data center Read more…

By Scott Tease

Leading Solution Providers

SC17 Booth Video Tours Playlist

Altair @ SC17

Altair

AMD @ SC17

AMD

ASRock Rack @ SC17

ASRock Rack

CEJN @ SC17

CEJN

DDN Storage @ SC17

DDN Storage

Huawei @ SC17

Huawei

IBM @ SC17

IBM

IBM Power Systems @ SC17

IBM Power Systems

Intel @ SC17

Intel

Lenovo @ SC17

Lenovo

Mellanox Technologies @ SC17

Mellanox Technologies

Microsoft @ SC17

Microsoft

Penguin Computing @ SC17

Penguin Computing

Pure Storage @ SC17

Pure Storage

Supericro @ SC17

Supericro

Tyan @ SC17

Tyan

Univa @ SC17

Univa

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