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!

Is Data Science the Fourth Pillar of the Scientific Method?

April 18, 2019

Nvidia CEO Jensen Huang revived a decade-old debate last month when he said that modern data science (AI plus HPC) has become the fourth pillar of the scientific method. While some disagree with the notion that statistic Read more…

By Alex Woodie

At ASF 2019: The Virtuous Circle of Big Data, AI and HPC

April 18, 2019

We've entered a new phase in IT -- in the world, really -- where the combination of big data, artificial intelligence, and high performance computing is pushing the bounds of what's possible in business and science, in w Read more…

By Alex Woodie with Doug Black and Tiffany Trader

Google Open Sources TensorFlow Version of MorphNet DL Tool

April 18, 2019

Designing optimum deep neural networks remains a non-trivial exercise. “Given the large search space of possible architectures, designing a network from scratch for your specific application can be prohibitively expens Read more…

By John Russell

HPE Extreme Performance Solutions

HPE and Intel® Omni-Path Architecture: How to Power a Cloud

Learn how HPE and Intel® Omni-Path Architecture provide critical infrastructure for leading Nordic HPC provider’s HPCFLOW cloud service.

powercloud_blog.jpgFor decades, HPE has been at the forefront of high-performance computing, and we’ve powered some of the fastest and most robust supercomputers in the world. Read more…

IBM Accelerated Insights

Bridging HPC and Cloud Native Development with Kubernetes

The HPC community has historically developed its own specialized software stack including schedulers, filesystems, developer tools, container technologies tuned for performance and large-scale on-premises deployments. Read more…

Interview with 2019 Person to Watch Michela Taufer

April 18, 2019

Today, as part of our ongoing HPCwire People to Watch focus series, we are highlighting our interview with 2019 Person to Watch Michela Taufer. Michela -- the General Chair of SC19 -- is an ACM Distinguished Scientist. Read more…

By HPCwire Editorial Team

At ASF 2019: The Virtuous Circle of Big Data, AI and HPC

April 18, 2019

We've entered a new phase in IT -- in the world, really -- where the combination of big data, artificial intelligence, and high performance computing is pushing Read more…

By Alex Woodie with Doug Black and Tiffany Trader

Interview with 2019 Person to Watch Michela Taufer

April 18, 2019

Today, as part of our ongoing HPCwire People to Watch focus series, we are highlighting our interview with 2019 Person to Watch Michela Taufer. Michela -- the Read more…

By HPCwire Editorial Team

Intel Gold U-Series SKUs Reveal Single Socket Intentions

April 18, 2019

Intel plans to jump into the single socket market with a portion of its just announced Cascade Lake microprocessor line according to one media report. This isn Read more…

By John Russell

BSC Researchers Shrink Floating Point Formats to Accelerate Deep Neural Network Training

April 15, 2019

Sometimes calculating solutions as precisely as a computer can wastes more CPU resources than is necessary. A case in point is with deep learning. In early stag Read more…

By Ken Strandberg

Intel Extends FPGA Ecosystem with 10nm Agilex

April 11, 2019

The insatiable appetite for higher throughput and lower latency – particularly where edge analytics and AI, network functions, or for a range of datacenter ac Read more…

By Doug Black

Nvidia Doubles Down on Medical AI

April 9, 2019

Nvidia is collaborating with medical groups to push GPU-powered AI tools into clinical settings, including radiology and drug discovery. The GPU leader said Monday it will collaborate with the American College of Radiology (ACR) to provide clinicians with its Clara AI tool kit. The partnership would allow radiologists to leverage AI techniques for diagnostic imaging using their own clinical data. Read more…

By George Leopold

Digging into MLPerf Benchmark Suite to Inform AI Infrastructure Decisions

April 9, 2019

With machine learning and deep learning storming into the datacenter, the new challenge is optimizing infrastructure choices to support diverse ML and DL workfl Read more…

By John Russell

AI and Enterprise Datacenters Boost HPC Server Revenues Past Expectations – Hyperion

April 9, 2019

Building on the big year of 2017 and spurred in part by the convergence of AI and HPC, global revenue for high performance servers jumped 15.6 percent last year Read more…

By Doug Black

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

Why Nvidia Bought Mellanox: ‘Future Datacenters Will Be…Like High Performance Computers’

March 14, 2019

“Future datacenters of all kinds will be built like high performance computers,” said Nvidia CEO Jensen Huang during a phone briefing on Monday after Nvidia revealed scooping up the high performance networking company Mellanox for $6.9 billion. Read more…

By Tiffany Trader

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

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

It’s Official: Aurora on Track to Be First US Exascale Computer in 2021

March 18, 2019

The U.S. Department of Energy along with Intel and Cray confirmed today that an Intel/Cray supercomputer, "Aurora," capable of sustained performance of one exaf 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

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

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

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

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

Arm Unveils Neoverse N1 Platform with up to 128-Cores

February 20, 2019

Following on its Neoverse roadmap announcement last October, Arm today revealed its next-gen Neoverse microarchitecture with compute and throughput-optimized si Read more…

By Tiffany Trader

France to Deploy AI-Focused Supercomputer: Jean Zay

January 22, 2019

HPE announced today that it won the contract to build a supercomputer that will drive France’s AI and HPC efforts. The computer will be part of GENCI, the Fre Read more…

By Tiffany Trader

Intel Launches Cascade Lake Xeons with Up to 56 Cores

April 2, 2019

At Intel's Data-Centric Innovation Day in San Francisco (April 2), the company unveiled its second-generation Xeon Scalable (Cascade Lake) family and debuted it Read more…

By Tiffany Trader

Oil and Gas Supercloud Clears Out Remaining Knights Landing Inventory: All 38,000 Wafers

March 13, 2019

The McCloud HPC service being built by Australia’s DownUnder GeoSolutions (DUG) outside Houston is set to become the largest oil and gas cloud in the world th Read more…

By Tiffany Trader

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

Intel Extends FPGA Ecosystem with 10nm Agilex

April 11, 2019

The insatiable appetite for higher throughput and lower latency – particularly where edge analytics and AI, network functions, or for a range of datacenter ac Read more…

By Doug Black

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