1. Clear Sailing for Allinea DDT at 700,000+ MPI Tasks on Blue Waters
Tough requirements and a tight timeline called for tools ready to deploy at the largest scales
A new scalability record has been set for Allinea DDT – the popular debugger installed on over
45 of the top 100 supercomputers. The debugger is being used on the Blue Waters
supercomputer by computational scientists at scale.
The machine was commissioned by the University of Illinois’s National Center for Science
Applications (NCSA) and the National Science Foundation (NSF). Blue Waters, a Cray
supercomputer, is the world’s fastest supercomputer on a university campus with a
theoretical capacity of 11.62 petaflops.
Blue Waters will be entirely available for open science. Projects will span the spectrum from
the minute to the cosmic, everything from examining the structure of viruses to predicting the
weather in outer space.
The Blue Waters team ran their own demanding acceptance trials while getting the machine
up to speed. They used Allinea DDT to debugg more than 700,000 MPI processes
simultaneously.
“Having Allinea DDT in the hands of users at this scale whenever the need arises and at any
scale – with its lightning fast performance and easy to use interface – is a critical part of
getting the scientific applications to super-petascale,” says David Lecomber, COO and founder
of Allinea.
The implementation of the Blue Waters system had a tough timeline – and having a debugger
ready to deploy at large scales was critical to meeting the schedule.
“We knew our tool was more than ready,” says Lecomber. “We wanted the NCSA to take
Allinea DDT to the extreme and see it first-hand, as real users. They came back with the news
that it was 30x faster than they specified in performing common debugging tasks—without

2. any extra tuning.”
System engineers at Cray knew they could count on Allinea because of its track record at
major labs such as the Oak Ridge Leadership Computing Facility, home of Titan, the world’s
fastest supercomputer.
“The exacting tools requirements of this project needed to be entrusted to a partner with the
ability to deliver,” said Peg Williams, Cray’s senior vice president of high performance
computing systems. “Allinea has proven a great partner for multiple Cray customer
installations and was ideal for the Blue Waters system. Their debugging tool is known for its
scalable performance and scalable user interface, which are matched to the requirements of
NCSA.”
"We set tough targets, and Allinea succeeded in providing a highly capable and usable
debugger at the full scale of the system. Allinea also showed flexibility in licensing so we can
ramp up and down and not just pay only for the largest possible case. Now our users can find
and fix problems up to full-machine size," said NCSA's Dr. William Kramer, Project Director for
Blue Waters. "Another great thing is Allinea DDT is usable on both our XE6 and XK7 nodes.
Allinea has already delivered training to our users and staff to help them to understand the
best practices for debugging HPC applications."
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Notes to Editors
Allinea Software is the trusted leader in software development tools for parallel programming
and high performance computing (HPC).
Leading users of HPC turn to Allinea for extremely scalable, capable and intuitive tools which
improve the efficiency and value of their HPC investment by reducing development time and
increasing application performance.
Its integrated suite of profiling and debugging tools is relied on from desktops through to
beyond Petascale for applications ranging from climate modeling to astrophysics, and from
finance to engine design.
Allinea has offices in the US and the UK, and a global network of resellers and partners.
For press enquiries, contact Rosie Evans: press@allinea.com, +44 (0)1926 623 231.
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