Some thoughts on Extreme Scale Computing

Some thoughts on Extreme
Scale Computing

David J. Dean

Senior Advisor

Under Secretary for Science

Department of Energy

The tools have changed rapidly

These were our supercomputers in

the 1970’s and 1980’s

1986:

X
-
MP/48 ~220
Mflop

sustained

120
-
150kW (depending on model)

$40M for
computer+disks

(FY09$)

NNSA:

Roadrunner
at 1.105 PF (
LINPACK)

LANL; 2.5 MW

SC/ASCR:

Jaguar
at
2.331
PF (
LINPACK)

ORNL; 6.9 MW

Factor 1x10
7

in speed

Factor of 18 in power

Today:

Various DOE computing assets serving the
DOE mission space

Machine

Place

Speed
(max)

On list
Since

Jaguar

ORNL

1.75 PF

2009 (1)

Roadrunner

LANL

1.04

PF

2009 (3)

Dawn

LLNL

0.478

PF

2007 (7)

BG/P

ANL

0.458 PF

2007 (8)

NERSC

LBL

0.266 PF

2008

(15)

Red

Storm

SNL

0.204

PF

2009 (17)

Top 500 list, November 2009


Leadership Computing: Scientific Progress at
the Petascale

Nuclear Energy

High
-
fidelity predictive
simulation tools for the design
of next
-
generation nuclear
reactors to safely increase
operating margins.



Fusion Energy

Substantial progress in the
understanding of anomalous
electron energy loss in the
National Spherical Torus
Experiment (NSTX).

Nano

Science

Understanding the atomic and
electronic properties of
nanostructures in next
-
generation photovoltaic solar
cell materials.

Turbulence

Understanding the statistical
geometry of turbulent
dispersion of pollutants in the
environment.

Energy Storage

Understanding the storage and
flow of energy in next
-
generation
nanostructured

carbon tube
supercapacitors

Biofuels

A comprehensive simulation model
of
lignocellulosic

biomass to
understand the bottleneck to
sustainable and economical ethanol
production.



All known sustained
petascale

science applications to date have been run on OLCF system

4

Process for identifying exascale
applications and technology for DOE
missions ensures broad community input

•
Town Hall Meetings April
-
June 2007

•
Scientific Grand Challenges Workshops
November 2008
–

October 2009

•
Climate Science (11/08),

•
High Energy Physics (12/08),

•
Nuclear Physics (1/09),

•
Fusion Energy (3/09),

•
Nuclear Energy (5/09),

•
Biology (8/09),

•
Material Science and Chemistry (8/09),

•
National Security (10/09)

•
Cross
-
cutting workshops

•
Architecture and Technology (12/09)

•
Architecture, Applied Mathematics and
Computer Science (2/10)

•
Meetings with industry (8/09, 11/09)

•
External Panels

•
ASCAC
Exascale

Charge

•
Trivelpiece Panel



MISSION IMPERATIVES

FUNDAMENTAL SCIENCE

5

Simulation enables fundamental
advances in basic science.

•
High Energy Physics

•
Understanding of Dark Energy and Dark
Matter

•
Testing QCD and physics beyond the
standard model

•
Nuclear Physics

•
Unification of nuclear physics from
quark
-
gluon plasma to basics of
nucleon structure to nucleosynthesis

•
Fundamental understanding of fission
and fusion reactions

•
Facility and experimental design

•
Effective design of accelerators

•
Probes of dark energy and dark matter

•
ITER shot planning and device control


6

ITER

ILC

Hubble image

of lensing

Structure of

nucleons

These breakthrough scientific
discoveries and facilities require
exascale applications and technologies.

Computing applied to problems of
National importance

•

Climate

•

Nuclear Energy

•

Smart Grid

•

Nuclear weapons

•

Materials under extremes

•

Combustion

•

Competitiveness

See ASCAC (Rosner Committee) and Trivelpiece reports

Simulations are a key part to solutions



Understand and control chemical and physical phenomena in
multicomponent

systems
from
femtoseconds

to millennia, at temperatures to 1000
°
C and radiation doses

to hundreds of displacements per atom

Example: Fundamental science challenge

for nuclear energy systems

•
Microstructural

evolution and phase stability

•
Mass transport, chemistry, and structural evolution

at interfaces

•
Chemical behavior in actinide and fission
-
product solutes

•
Solution phenomena

•
Nuclear, chemical, and
thermomechanical

phenomena

in fuels and waste forms

•
First
-
principles theory for ƒ
-
electron complexes and
materials

•
Predictive capability across length and time scales

•
Material failure mechanisms

Basic Research Needs for Advanced Nuclear Energy Systems
, Gaithersburg (2006)

8

Example
: The next decade will see Nuclear
Energy models spanning multiple time and
length scales.

9

Bridging length and time scales to resolve scientific unknowns [in nuclear energy] will
require 3D simulations 100x standard resolution = A 10 Exaflop problem.

Science
-
Based, Nuclear Energy Systems Enabled by Advanced Modeling and
Simulation at the Extreme Scale


Critical
Exascale

Technology Investments

10

•

System power
is a first class constraint on
exascale

system performance and effectiveness.


• M
emory
is an important component of meeting
exascale

power and applications goals.


•
Programming model.
Early investment in several efforts to decide in 2013 on
exascale

programming model, allowing exemplar applications effective access to 2015 system for both
mission and science.


•
Investment in
exascale

processor design
to achieve an
exascale
-
like system in 2015.


•
Operating System strategy
for
exascale

is critical for node performance at scale and for
efficient support of new programming models and run time systems.


•
Reliability and resiliency
are critical at this scale and require applications neutral movement of
the file system (for check pointing, in particular) closer to the running apps.


•
HPC co
-
design strategy and implementation

requires a set of a hierarchical performance
models and simulators as well as commitment from apps, software and architecture communities.

Co
-
design expands the feasible

solution space to allow better solutions

11

Exascale

Computing


Need:


Enable dramatic advances in climate modeling, energy technologies,
national security, and science via development of next
-
generation HPC


Challenges:


Next 1000x improvement in computing capability cannot be achieved by
simply scaling up today’s hardware


Power consumption needs to be dramatically reduced to make
exascale

feasible


Millions of processors will present significant challenges for
concurrency and resiliency


New programming models will be required to exploit new architectures


Applications, programming environment, and hardware must be co
-
developed


New architectures will require rethinking applications and programming
environment from the ground up


12

Exascale

Computing Path Forward


We have begun exploratory research efforts (FY10
-
11)


A concerted program would be:


Goal:
exascale

capability by the end of the decade


Lab/industry/academic partnerships to begin hardware and
programming environment R&D


Focus on key applications, including climate, nuclear security, Energy
Simulation topics


High level coordination required to ensure multiple research

programs are appropriately integrated


13