OpenACC Expands Community, Reveals Roadmap Details

By Tiffany Trader

November 7, 2016

In advance of the SC16 expo in Salt Lake City next week, the OpenACC standards group today welcomed newest member NSSC-Wuxi and highlighted a number of important developments for the directives-based programming standard. Ahead of the announcement, HPCwire spoke with Michael Wolfe, technical director of OpenACC, and Duncan Poole, OpenACC president and director of platform alliances for accelerated computing at Nvidia.

OpenACC (Open Accelerators) was developed by Cray, CAPS, Nvidia and PGI circa 2011. The standard was designed to simplify parallel programming of heterogenous CPU-GPU machines and has since added support for additional multicore/manycore platforms, while maintaining code portability.

OpenACC’s newest member is the National Supercomputing Center (NSCC) in Wuxi, China, home to the TaihuLight Sunway system, which made its grand TOP500 entrance at ISC 2016, pushing the LINPACK record to 93 petaflops. NSCC-Wuxi runs a custom version of OpenACC developed for the Sunway system’s 260-core Chinese-made processor.

“The OpenACC paradigm was chosen for its better fit to our many-core processor, with a few extensions to better support the efficient utilization of the new hardware features such as the Scratch Pad Memory for each core and DMA instructions,” said Dr. Haohuan Fu, deputy director of the National Supercomputing Center in Wuxi and associate professor Center for Earth System Science at Tsinghua University, in a prepared statement.

TaihuLight’s Sunway manycore processors are composed of four core groups; each core group has one management processing element (MPE) and 64 compute processing elements (CPEs) for a total of 260 cores per CPU. Says Wolfe, who is also a compiler engineer with PGI (Nvidia), “Essentially, there’s a control processor that runs the main application and offloads the parallel region to the compute elements. When they’re using OpenMP the offload model offloads the parallel part to the compute elements and the master thread goes on with the scalar part of the code. NSCC-Wuxi wanted that master thread to participate in the parallel work and thought that would be more natural with the OpenACC model.” Wolfe added that OpenMP also has a lot of synchronization constructs that are challenging to implement on the manycore architecture.

OpenACC was used to parallelize and tune one of three NSCC-Wuxi codes on the short-list to receive the prestigious Gordon Bell prize at SC16. CAM-SE is a “10 million core scalable fully-implicit solver for nonhydrostatic atmospheric dynamics” that contains 530,000 lines of code.

A number of flagship HPC codes are also using OpenACC, notably Gaussian, widely-used in quantum chemistry, and ANSYS Fluent, the popular commercial CFD software. “We build and support Fluent on a wide variety of parallel computing systems, and we need to be able to write a single version of our source code that runs efficiently on all of those systems,” said Sunil Sathe, Fluent lead software developer. “With OpenACC, we were able to quickly enable a key solver for GPU acceleration while keeping the same code base for CPU execution. The OpenACC performance was excellent on NVIDIA GPUs and very competitive on CPUs.”

OpenACC is also being used by five of the thirteen application-readiness codes used to qualify the 200-petaflops Summit supercomputer that is going in at Oak Ridge Labs. “This shouldn’t be a surprise because the Oak Ridge Leadership Computing Facility is a big OpenACC user today,” said Duncan Poole, president of OpenACC and Nvidia executive.openacc-2015-2017

OpenACC also has production support for OpenPower, both multicore OpenPOWER and CPU + GPU implementations. Poole said that support for manycore Xeon CPUs (i.e., the Knight Landing Phi and follow-ons) is on track for 2017. The latter will be key for the Summit supercomputer, which will have some 3,400 nodes comprising multiple Power9 CPUs and multiple NVIDIA Volta GPUs, connected with Nvidia’s second-generation NVLink technology. For more information about how OpenACC is supporting the OpenPower architecture, see our June coverage.

The OpenACC roadmap

OpenACC also previewed features that will be added to its next release (2.6), being targeted for the middle of next year. One of the key features that’s been requested by users for the last couple years is “deep copy.” When we talked with Wolfe last year at this time, he said deep copy was being targeted for the 3.0 release, but now the standards body is planning a sort of interim step, to enable OpenACC to support a manual deep copy.

Wolfe explains, “This is where you have deeply nested data structures with pointers to other data structures that have pointers to other data structures and want to move the whole structure over to the device, which is a different memory space with different addresses and still keep the pointers valid.

“We’ve been struggling with a way to define this in manner that is seamless to use and still performant. We arrived at the decision to make a small change to the specification so that users can do a manual deep copy.”

Manual deep copy gives users the behavior that they want although it’s not as conventient as they would like, Wolfe commented. The standards group is looking for someone to do an implementation of the true deep copy before it is hardened into the specification. Wolfe wouldn’t speculate on a timeline: “If we can get a prototype implementation, our hope is that that may shake out potential problems, but we cannot predict how many of those there might me.”

Additional features planned for OpenACC include Device Query Routines, Error Callback Routine, Polymorphic Routine Compilation, Serial Compute Construct, and Array Reductions.

These are all highly requested by users, the actual people working on programs, said Wolfe.


OpenACC doesn’t have a calendar-based release cadence. Instead, they collect requests and push out a new release when they have a critical mass to constitute a new release.

“What we want to work on is the big items, things like true deep copy or a seamless way to spread parallel regions across multiple devices, or load balancing across the GPU and the CPU and how do you manage that. Those are big items; those are what users really want,” said Wolfe.

He added, “Last summer I was visiting CSCS in Lugano, Switzerland, and each node of the cluster they host for the weather forecasting service MateoSwiss has four K80s, so eight GPUs per node. Well how do you manage that? Is it easy or is there a way to make it even easier, that’s a big challenge, and we’re ready to take it on.”

Community engagement and education

Via partnerships with Oak Ridge National Laboratory and other member orgs, OpenACC continues to offer hackathons around the world. More info is at Oak Ridge and OpenACC will also be conducting a series of free two and half day workshops starting next year. These are designed to introduce developers to the framework and are a new addition to OpenACC’s training and education program.

SC16 activities include:

OpenACC Birds of a Feather, Wed. Nov. 16th 5:30–7:00PM in room 155-C. Discussion will include such topics as “Should OpenACC and OpenMP ever merge”.

Free “Parallel Programming with OpenACC” books will be signed by author Rob Farber Monday, November 14 from 7:00 to 9:00 pm in the OpenACC booth #634.

Bringing About HPC Open-Standards World Peace, Nov. 16th, 10:30 am 255-BC

Members will be available for questions in the OpenACC booth #634.

Visit for a list of all OpenACC member activities.

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!

Insights from Optimized Codes on Cineca’s Marconi

February 15, 2019

What can you do with 381,392 CPU cores? For Cineca, it means enabling computational scientists to expand a large part of the world’s body of knowledge from the nanoscale to the astronomic, from calculating quantum effe Read more…

By Ken Strandberg

What Will IBM’s AI Debater Learn from Its Loss?

February 14, 2019

The utility of IBM’s latest man-versus-machine gambit is debatable. At the very least its Project Debater got us thinking about the potential uses of artificial intelligence as a way of helping humans sift through al Read more…

By George Leopold

ClusterVision in Bankruptcy, Fate Uncertain

February 13, 2019

ClusterVision, European HPC specialists that have built and installed over 20 Top500-ranked systems in their nearly 17-year history, appear to be in the midst of bankruptcy proceedings. According to Dutch news site Drimb Read more…

By Tiffany Trader

HPE Extreme Performance Solutions

HPE Systems With Intel Omni-Path: Architected for Value and Accessible High-Performance Computing

Today’s high-performance computing (HPC) and artificial intelligence (AI) users value high performing clusters. And the higher the performance that their system can deliver, the better. Read more…

IBM Accelerated Insights

Medical Research Powered by Data

“We’re all the same, but we’re unique as well. In that uniqueness lies all of the answers….”

  • Mark Tykocinski, MD, Provost, Executive Vice President for Academic Affairs, Thomas Jefferson University

Getting the answers to what causes some people to develop diseases and not others is driving the groundbreaking medical research being conducted by the Computational Medicine Center at Thomas Jefferson University in Philadelphia. Read more…

South African Weather Service Doubles Compute and Triples Storage Capacity of Cray System

February 13, 2019

South Africa has made headlines in recent years for its commitment to HPC leadership in Africa – and now, Cray has announced another major South African HPC expansion. Cray has been awarded contracts with Eclipse Holdings Ltd. to upgrade the supercomputing system operated by the South African Weather Service (SAWS). Read more…

By Oliver Peckham

Insights from Optimized Codes on Cineca’s Marconi

February 15, 2019

What can you do with 381,392 CPU cores? For Cineca, it means enabling computational scientists to expand a large part of the world’s body of knowledge from th Read more…

By Ken Strandberg

ClusterVision in Bankruptcy, Fate Uncertain

February 13, 2019

ClusterVision, European HPC specialists that have built and installed over 20 Top500-ranked systems in their nearly 17-year history, appear to be in the midst o Read more…

By Tiffany Trader

UC Berkeley Paper Heralds Rise of Serverless Computing in the Cloud – Do You Agree?

February 13, 2019

Almost exactly ten years to the day from publishing of their widely-read, seminal paper on cloud computing, UC Berkeley researchers have issued another ambitious examination of cloud computing - Cloud Programming Simplified: A Berkeley View on Serverless Computing. The new work heralds the rise of ‘serverless computing’ as the next dominant phase of cloud computing. Read more…

By John Russell

Iowa ‘Grows Its Own’ to Fill the HPC Workforce Pipeline

February 13, 2019

The global workforce that supports advanced computing, scientific software and high-speed research networks is relatively small when you stop to consider the magnitude of the transformative discoveries it empowers. Technical conferences provide a forum where specialists convene to learn about the latest innovations and schedule face-time with colleagues from other institutions. Read more…

By Elizabeth Leake, STEM-Trek

Trump Signs Executive Order Launching U.S. AI Initiative

February 11, 2019

U.S. President Donald Trump issued an Executive Order (EO) today launching a U.S Artificial Intelligence Initiative. The new initiative - Maintaining American L Read more…

By John Russell

Celebrating Women in Science: Meet Four Women Leading the Way in HPC

February 11, 2019

One only needs to look around at virtually any CS/tech conference to realize that women are underrepresented, and that holds true of HPC. SC hosts over 13,000 H Read more…

By AJ Lauer

IBM Bets $2B Seeking 1000X AI Hardware Performance Boost

February 7, 2019

For now, AI systems are mostly machine learning-based and “narrow” – powerful as they are by today's standards, they're limited to performing a few, narro Read more…

By Doug Black

Assessing Government Shutdown’s Impact on HPC

February 6, 2019

After a 35-day federal government shutdown, the longest in U.S. history, government agencies are taking stock of the damage -- and girding for a potential secon Read more…

By Tiffany Trader

Quantum Computing Will Never Work

November 27, 2018

Amid the gush of money and enthusiastic predictions being thrown at quantum computing comes a proposed cold shower in the form of an essay by physicist Mikhail Read more…

By John Russell

Cray Unveils Shasta, Lands NERSC-9 Contract

October 30, 2018

Cray revealed today the details of its next-gen supercomputing architecture, Shasta, selected to be the next flagship system at NERSC. We've known of the code-name "Shasta" since the Argonne slice of the CORAL project was announced in 2015 and although the details of that plan have changed considerably, Cray didn't slow down its timeline for Shasta. Read more…

By Tiffany Trader

The Case Against ‘The Case Against Quantum Computing’

January 9, 2019

It’s not easy to be a physicist. Richard Feynman (basically the Jimi Hendrix of physicists) once said: “The first principle is that you must not fool yourse Read more…

By Ben Criger

AMD Sets Up for Epyc Epoch

November 16, 2018

It’s been a good two weeks, AMD’s Gary Silcott and Andy Parma told me on the last day of SC18 in Dallas at the restaurant where we met to discuss their show news and recent successes. Heck, it’s been a good year. Read more…

By Tiffany Trader

Intel Reportedly in $6B Bid for Mellanox

January 30, 2019

The latest rumors and reports around an acquisition of Mellanox focus on Intel, which has reportedly offered a $6 billion bid for the high performance interconn Read more…

By Doug Black

US Leads Supercomputing with #1, #2 Systems & Petascale Arm

November 12, 2018

The 31st Supercomputing Conference (SC) - commemorating 30 years since the first Supercomputing in 1988 - kicked off in Dallas yesterday, taking over the Kay Ba Read more…

By Tiffany Trader

Looking for Light Reading? NSF-backed ‘Comic Books’ Tackle Quantum Computing

January 28, 2019

Still baffled by quantum computing? How about turning to comic books (graphic novels for the well-read among you) for some clarity and a little humor on QC. The Read more…

By John Russell

Contract Signed for New Finnish Supercomputer

December 13, 2018

After the official contract signing yesterday, configuration details were made public for the new BullSequana system that the Finnish IT Center for Science (CSC Read more…

By Tiffany Trader

Leading Solution Providers

SC 18 Virtual Booth Video Tour

Advania @ SC18 AMD @ SC18
ASRock Rack @ SC18
DDN Storage @ SC18
HPE @ SC18
IBM @ SC18
Lenovo @ SC18 Mellanox Technologies @ SC18
One Stop Systems @ SC18
Oracle @ SC18 Panasas @ SC18
Supermicro @ SC18 SUSE @ SC18 TYAN @ SC18
Verne Global @ SC18

Deep500: ETH Researchers Introduce New Deep Learning Benchmark for HPC

February 5, 2019

ETH researchers have developed a new deep learning benchmarking environment – Deep500 – they say is “the first distributed and reproducible benchmarking s Read more…

By John Russell

ClusterVision in Bankruptcy, Fate Uncertain

February 13, 2019

ClusterVision, European HPC specialists that have built and installed over 20 Top500-ranked systems in their nearly 17-year history, appear to be in the midst o Read more…

By Tiffany Trader

IBM Quantum Update: Q System One Launch, New Collaborators, and QC Center Plans

January 10, 2019

IBM made three significant quantum computing announcements at CES this week. One was introduction of IBM Q System One; it’s really the integration of IBM’s Read more…

By John Russell

Nvidia’s Jensen Huang Delivers Vision for the New HPC

November 14, 2018

For nearly two hours on Monday at SC18, Jensen Huang, CEO of Nvidia, presented his expansive view of the future of HPC (and computing in general) as only he can do. Animated. Backstopped by a stream of data charts, product photos, and even a beautiful image of supernovae... Read more…

By John Russell

HPC Reflections and (Mostly Hopeful) Predictions

December 19, 2018

So much ‘spaghetti’ gets tossed on walls by the technology community (vendors and researchers) to see what sticks that it is often difficult to peer through Read more…

By John Russell

IBM Bets $2B Seeking 1000X AI Hardware Performance Boost

February 7, 2019

For now, AI systems are mostly machine learning-based and “narrow” – powerful as they are by today's standards, they're limited to performing a few, narro Read more…

By Doug Black

The Deep500 – Researchers Tackle an HPC Benchmark for Deep Learning

January 7, 2019

How do you know if an HPC system, particularly a larger-scale system, is well-suited for deep learning workloads? Today, that’s not an easy question to answer Read more…

By John Russell

Intel Confirms 48-Core Cascade Lake-AP for 2019

November 4, 2018

As part of the run-up to SC18, taking place in Dallas next week (Nov. 11-16), Intel is doling out info on its next-gen Cascade Lake family of Xeon processors, specifically the “Advanced Processor” version (Cascade Lake-AP), architected for high-performance computing, artificial intelligence and infrastructure-as-a-service workloads. Read more…

By Tiffany Trader

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