Exterminating at Extreme Scale

By Nicole Hemsoth

May 7, 2013

Since the first bug was eradicated from a Mark II system at Harvard in 1940s (an actual moth wedged in a relay, which drove the machine to a standstill) system exterminators have faced a constant spray of challenges. Nodes continue to reproduce, architectures alter, and application demands climb ever-higher walls.  

This all means it’s getting tougher for code exterminators to reproduce and track down the bugs across many thousands of cores. Further, many pre-petascale debuggers weren’t able to efficiently relay information about the health of the entire application, allowing a small portal to see one process at a time, despite the fact that hundreds were being debugged alongside.

Throw  coprocessors and accelerators into the mix and it seems there’s a perfect storm brewing for a total rethink in more efficient, scalable bug-zapping—especially with the spectre of exascale in the distance.

According to David Lecomber, co-founder and COO of HPC debugging company, Allinea, the scale and complexity of systems it’s been working with, including Titan and Blue Waters, required new approaches to tackle larger node counts. More pressing and complex, however, is the increased heterogeneity. For top-tier machines like these, he says, scale and core diversity are critical–but at the heart of all of their work is improving debugging speed. The company has targeted all of these areas as it’s worked alongside Oak Ridge National Lab, NCSA, and others aiming for extreme scale computing targets, refining its ability to show thousands of processes in one, full view for more effective bug stomping.

In the “moth-plucking” days of debugging, before visually-oriented, multi-process, scalable approaches, every single node in a cluster had to directly connect to where the user was sitting. Naturally, as node counts climbed, the workstations were quickly overloaded, meaning users could only handle at most several hundred or a thousand cores. Debugging was a necessary, clunky of evil—one that wouldn’t hold up to the demands of core counts in the hundreds of thousands, and even if it could keep up, it would slow to a crawl.

Lecomber touts his company’s role in reshaping that long-standing trend via Allinea’s DDT, which offered a UI that could paint the whole landscape of an application, letting users “visualize and compare 200,000 processes as simply as two.” Their work at massive scale recently started in earnest with Jaguar via their work with Oak Ridge, before wading into Blue Waters or battling the Titan. He claims that despite the scale, the speed was emphasized—to the point that Allinea could handle even higher node counts in anything we’re set to see soon. He said that the time to debug using the old node-connected approach was in the minutes, but they’ve been able to trim this process down to seconds.

During the company’s early work with Jaguar, and later Titan, Oak Ridge had a couple of problems, including limitations with the traditional printfs debugging approach to find bugs, followed by adding GPUs into the mix. Oak Ridge’s Tools Project Technical Officer, Joshua Ladd said that the ability to see every process in a parallel job allowed the lab to remove the debugging hassles and speed time to result.

And on the GPU front, the lab wanted researchers to take advantage of Titan’s accelerators but they needed more powerful tools that could attack those more complicated bugs. Further, Oak Ridge was able to harness DDT on Jaguar to debug an open source implementation of MPI at a half-million lines of code across a maximum of 225,000 cores.

Scale aside, as noted, the true challenges relate to the increasing heterogeneity of ever-larger systems. Lecomber said that a lot of work went on behind the scenes to get DDT primed for GPUs and coprocessors, and he expects such challenges are going to persist during the exascale climb. They’ve already done a great deal of work on accelerators and recently looked to address challenges on Xeon Phi, as detailed below.

Beyond new architectures, Allinea is focusing on combining advanced debugging and performance tools so users will be able to better visualize the performance of their applications. In other words, having a petascale machine isn’t incredibly useful if you can’t take advantage of that power—just as computing the fastest wrong answer won’t work either.

When it comes to exascale, and even petascale at this point, “the real gaps are in the tools area, the people writing applications for these large machines need to be able to do performance profiling in a similar way as they handle debugging—visually and with emphasis on speed,” he said. Their MPI profiler, called MAP, highlights lines of code that executed the slowest to demo what happened during the run in a format that will be familiar to those who already use DDT.

While we generally hear about HPC debuggers in the context of national labs, petascale systems are proliferating in the commercial spaces as well, necessitating enterprise-grade, extreme-scale extermination. Lecomber says that companies they work with, several of which are in the oil and gas and engineering arenas, are adopting similarly-sized systems that present mission-critical challenges. Simulating the performance and safety of an engine, for instance, can have devastating results if not done correctly or at best, can result in expensive runtime waste.

Aside from their academic affiliations and work in oil and gas and other key commercial areas, Allinea is working closely with the European Collaborative Research into Exascale Systemware, Tools and Applications (CRESTA) to identify what these future systems will look like and how tool vendors and application artists will need to rework their approaches. Lecomber says this also involves collaboration with system designers, processor-makers and other vendors to make sure the exascale research food chain is aligned.

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!

Live and in Color, Meet the European Student Cluster Teams

November 21, 2017

The SC17 Student Cluster Competition welcomed two teams from Europe, the German team of FAU/TUC and Team Poland, the pride of Warsaw. Let's get to know them better through the miracle of video..... Team FAU/TUC is a c Read more…

By Dan Olds

SC17 Student Cluster Kick Off – Guts, Glory, Grep

November 21, 2017

The SC17 Student Cluster Competition started with a well-orchestrated kick-off emceed by Stephen Harrell, the competition chair. It began with a welcome from SC17 chair Bernd Mohr, where he lauded the competition for Read more…

By Dan Olds

Activist Investor Starboard Buys 10.7% Stake in Mellanox; Sale Possible?

November 20, 2017

Starboard Value has reportedly taken a 10.7 percent stake in interconnect specialist Mellanox Technologies, and according to the Wall Street Journal, has urged the company “to improve its margins and stock and explore Read more…

By John Russell

HPE Extreme Performance Solutions

Harness Scalable Petabyte Storage with HPE Apollo 4510 and HPE StoreEver

As a growing number of connected devices challenges IT departments to rapidly collect, manage, and store troves of data, organizations must adopt a new generation of IT to help them operate quickly and intelligently. Read more…

Installation of Sierra Supercomputer Steams Along at LLNL

November 20, 2017

Sierra, the 125 petaflops (peak) machine based on IBM’s Power9 chip being built at Lawrence Livermore National Laboratory, sometimes takes a back seat to Summit, the ~200 petaflops system being built at Oak Ridge Natio Read more…

By John Russell

Live and in Color, Meet the European Student Cluster Teams

November 21, 2017

The SC17 Student Cluster Competition welcomed two teams from Europe, the German team of FAU/TUC and Team Poland, the pride of Warsaw. Let's get to know them bet Read more…

By Dan Olds

SC17 Student Cluster Kick Off – Guts, Glory, Grep

November 21, 2017

The SC17 Student Cluster Competition started with a well-orchestrated kick-off emceed by Stephen Harrell, the competition chair. It began with a welcome from Read more…

By Dan Olds

SC Bids Farewell to Denver, Heads to Dallas for 30th

November 17, 2017

After a jam-packed four-day expo and intensive six-day technical program, SC17 has wrapped up another successful event that brought together nearly 13,000 visit Read more…

By Tiffany Trader

SC17 Keynote – HPC Powers SKA Efforts to Peer Deep into the Cosmos

November 17, 2017

This week’s SC17 keynote – Life, the Universe and Computing: The Story of the SKA Telescope – was a powerful pitch for the potential of Big Science projects that also showcased the foundational role of high performance computing in modern science. It was also visually stunning. Read more…

By John Russell

How Cities Use HPC at the Edge to Get Smarter

November 17, 2017

Cities are sensoring up, collecting vast troves of data that they’re running through predictive models and using the insights to solve problems that, in some Read more…

By Doug Black

Student Cluster LINPACK Record Shattered! More LINs Packed Than Ever before!

November 16, 2017

Nanyang Technological University, the pride of Singapore, utterly destroyed the Student Cluster Competition LINPACK record by posting a score of 51.77 TFlop/s a Read more…

By Dan Olds

Hyperion Market Update: ‘Decent’ Growth Led by HPE; AI Transparency a Risk Issue

November 15, 2017

The HPC market update from Hyperion Research (formerly IDC) at the annual SC conference is a business and social “must,” and this year’s presentation at S Read more…

By Doug Black

Nvidia Focuses Its Cloud Containers on HPC Applications

November 14, 2017

Having migrated its top-of-the-line datacenter GPU to the largest cloud vendors, Nvidia is touting its Volta architecture for a range of scientific computing ta Read more…

By George Leopold

US Coalesces Plans for First Exascale Supercomputer: Aurora in 2021

September 27, 2017

At the Advanced Scientific Computing Advisory Committee (ASCAC) meeting, in Arlington, Va., yesterday (Sept. 26), it was revealed that the "Aurora" supercompute Read more…

By Tiffany Trader

NERSC Scales Scientific Deep Learning to 15 Petaflops

August 28, 2017

A collaborative effort between Intel, NERSC and Stanford has delivered the first 15-petaflops deep learning software running on HPC platforms and is, according Read more…

By Rob Farber

Oracle Layoffs Reportedly Hit SPARC and Solaris Hard

September 7, 2017

Oracle’s latest layoffs have many wondering if this is the end of the line for the SPARC processor and Solaris OS development. As reported by multiple sources Read more…

By John Russell

AMD Showcases Growing Portfolio of EPYC and Radeon-based Systems at SC17

November 13, 2017

AMD’s charge back into HPC and the datacenter is on full display at SC17. Having launched the EPYC processor line in June along with its MI25 GPU the focus he Read more…

By John Russell

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

Google Releases Deeplearn.js to Further Democratize Machine Learning

August 17, 2017

Spreading the use of machine learning tools is one of the goals of Google’s PAIR (People + AI Research) initiative, which was introduced in early July. Last w Read more…

By John Russell

GlobalFoundries Puts Wind in AMD’s Sails with 12nm FinFET

September 24, 2017

From its annual tech conference last week (Sept. 20), where GlobalFoundries welcomed more than 600 semiconductor professionals (reaching the Santa Clara venue Read more…

By Tiffany Trader

Amazon Debuts New AMD-based GPU Instances for Graphics Acceleration

September 12, 2017

Last week Amazon Web Services (AWS) streaming service, AppStream 2.0, introduced a new GPU instance called Graphics Design intended to accelerate graphics. The Read more…

By John Russell

Leading Solution Providers

EU Funds 20 Million Euro ARM+FPGA Exascale Project

September 7, 2017

At the Barcelona Supercomputer Centre on Wednesday (Sept. 6), 16 partners gathered to launch the EuroEXA project, which invests €20 million over three-and-a-half years into exascale-focused research and development. Led by the Horizon 2020 program, EuroEXA picks up the banner of a triad of partner projects — ExaNeSt, EcoScale and ExaNoDe — building on their work... Read more…

By Tiffany Trader

Delays, Smoke, Records & Markets – A Candid Conversation with Cray CEO Peter Ungaro

October 5, 2017

Earlier this month, Tom Tabor, publisher of HPCwire and I had a very personal conversation with Cray CEO Peter Ungaro. Cray has been on something of a Cinderell Read more…

By Tiffany Trader & Tom Tabor

Cray Moves to Acquire the Seagate ClusterStor Line

July 28, 2017

This week Cray announced that it is picking up Seagate's ClusterStor HPC storage array business for an undisclosed sum. "In short we're effectively transitioning the bulk of the ClusterStor product line to Cray," said CEO Peter Ungaro. Read more…

By Tiffany Trader

Reinders: “AVX-512 May Be a Hidden Gem” in Intel Xeon Scalable Processors

June 29, 2017

Imagine if we could use vector processing on something other than just floating point problems.  Today, GPUs and CPUs work tirelessly to accelerate algorithms Read more…

By James Reinders

Intel Launches Software Tools to Ease FPGA Programming

September 5, 2017

Field Programmable Gate Arrays (FPGAs) have a reputation for being difficult to program, requiring expertise in specialty languages, like Verilog or VHDL. Easin Read more…

By Tiffany Trader

HPC Chips – A Veritable Smorgasbord?

October 10, 2017

For the first time since AMD's ill-fated launch of Bulldozer the answer to the question, 'Which CPU will be in my next HPC system?' doesn't have to be 'Whichever variety of Intel Xeon E5 they are selling when we procure'. Read more…

By Dairsie Latimer

Flipping the Flops and Reading the Top500 Tea Leaves

November 13, 2017

The 50th edition of the Top500 list, the biannual publication of the world’s fastest supercomputers based on public Linpack benchmarking results, was released Read more…

By Tiffany Trader

IBM Advances Web-based Quantum Programming

September 5, 2017

IBM Research is pairing its Jupyter-based Data Science Experience notebook environment with its cloud-based quantum computer, IBM Q, in hopes of encouraging a new class of entrepreneurial user to solve intractable problems that even exceed the capabilities of the best AI systems. Read more…

By Alex Woodie

Share This