Supercomputer Scientists Take Control of Code Performance with Allinea MAP

Mon March 18, 2013

Allinea MAP is a new performance-analysis tool scientists and HPC performance experts alike can use to rapidly spot performance problems in complex codes.

 

Allinea MAP - MPI profilerWarwick, UK – Allinea Software has today cracked the performance profiling pain barrier with the release of Allinea MAP, a powerful performance-analysis tool easy enough for scientists to diagnose problems in their own code.

 

“People have tried to make a profiler that scientists could use themselves, but until now no commercial company has put the time and resources into getting the user experience right,” says Mark O’Connor, Allinea Software’s VP of Product Management.

 

CEA"In 2011, we recognized that software development would be one of the most serious challenges to scaling applications to the levels of extreme core counts that our scientific goals require”, recalls François Robin, IFERC/CSC Project Leader for CEA. “We needed not only highly scalable debugging tools, but also a capable and easy-to-use performance tool that could reach the extreme. Allinea Software's strong reputation for scalable development tools and for collaboration made them the obvious partner that could deliver."

 

No compiling – just clear results

 

Allinea MAP runs without the need to instrument or compile with special options. The program annotates the source code with performance information in colored graphs so users can see any problems at a glance.

 

“Our scientific users immediately grasp the graphical nature used to show how time spent on computation and communication varies for each line of code - this gives them an intuitive understanding of where problems lie so they can assess whether to call in an HPC performance expert for help,” says O’Connor.

 

Scalable but not data intensive

 

Allinea MAP is a lightweight application that adds little overhead even when scaled up to profile tens of thousands of processes.

 

“People assumed if you were to profile at scale, you’d need to store huge amounts of data — gigabytes or even terabytes. They were amazed that Allinea MAP stores only 10 to 20 megabytes,” says O’Connor.

 

Allinea Software is also the creator of Allinea DDT, a popular debugging tool proven at more than 700,000 cores and installed on the majority of the top supercomputers. Allinea MAP is built on the same infrastructure, making it possible to work on a very large scale while adding only 5% to the total runtime.

 

insideHPC“I think visual tools like Allinea MAP are the only way forward as we approach the daunting complexity of exascale computing,” says Rich Brueckner, president of the popular insideHPC news blog.

 

“Algorithms that scale at hundreds or thousands of nodes tend to behave very differently at ultra-scale, where one has tens of thousands or even millions of nodes to contend with,” says Brueckner. “How one tackles such a problem requires new approaches and ways of thinking. You are never going to make parallel computing easy. What you can do is give the programmer a way to navigate in an ocean of code.”

 

Allinea MAP can be combined with Allinea DDT, sharing a single interface, so when Allinea MAP shows where performance bottlenecks are forming, you can flip to the Allinea DDT view and step through the code to find the source of the problem.

 

A worldwide collaborative process

 

Allinea Software crowd-sourced the development of Allinea MAP with industry experts all over the world giving feedback on each iteration, from the whiteboard stage up to the release.

 

the warwick uni blueOliver Perks and David Beckingsale, members of the University of Warwick’s Performance Computing and Visualisation Group, helped Allinea MAP evolve from a tool emphasizing source code to the visually rich interface it sports today.

 

“The fact you can see the visual overview without delving into the numbers is incredibly useful - Allinea MAP saves days in preparing code for a supercomputer,” says Perks.

 

Steven Jarvis, head of the High Performance Systems Group at Warwick University agrees - "Allinea MAP provides access to key performance metrics in a lightweight and intuitive framework, allowing us to profile code performance faster."

 

With a tool that helps scientists see for themselves how performance bottlenecks form, the aim is to foster a culture of performance awareness rather than just fixing problems when they become too large to ignore.

 

“A lot of code out there is performing badly because the people who write and run it don’t have tools to rapidly and regularly analyze it. We’ve had HPC experts tell us they have to correct the same basic mistakes time after time,” says O’Connor. “A single optimization found with Allinea MAP can save hundreds of thousands of core hours over the lifetime of the code, delivering results faster and letting scientists focus on their real work instead of fighting the tools.”