Parallel Scaling
Nanoelectronic Modeling may require significant computational resources. Benchmarking of two differenc codes is described here:
NEMO 1-D computes current flow in 1-D heterostructures where typically a double integral over momentum and energy is solved for many different bais points. The theory is based on the non-equilibriu Green function formalism. NEMO 1-D has been demonstrated to scale up to 23,000 processors in July of 2007 on ORNL's Cray XT3/4. Scaling experiments on various other TOP500 machines have also been performed.
NEMO 3-D computes electrnic structure in multi-million atom systems. The basic operation is the solution of an interior eigenvalue problem and requires a large number of sparse-matrix vector multiplies. NEMO 3-D has been demonstrated to scale to 8,192 cores in July of 2007 on various TOP500 machines. Details of the various scalings on these machines are available.
Parallelization work of NEMO 1-D began 1998 at the Jet Propulsion laboratory with compiler based parallelization and continued with tri-level MPI-based parallelization [40].
NEMO 3-D was immediately designed as a parallel code.
Several other benchmarks stemming from the early JPL work are also available.
- Compiler-based parallelization and benchmarking of the original NEMO-1D code.
- MPI-based parallelization of the original NEMO-1D code in loops corresponding to bias points, and integrations of the transverse momentum and energy.
- MPI-based parallelization of the NEMO-3D code:
- Benchmarks on a 32 CPU Beowulf cluster (Pentium III, 450 MHz)
- Benchmarks comparing a 32 CPU Beowulf (450MHz) to a 20 node dual CPU Beowulf (800MHz).
- Benchmarks on an SGI Origin 2000 compared to our Beowulf
- MPI-based parallel genetic algorithm package usage and code developmend (GENES).
NEMO 1-D scaling to 23,000 cores Scaling on ORNL Cray XT3/4 Benchmark 6 on Cray XT3/4 |
NEMO 1-D scaling to 23,000 cores Scaling on ORNL Cray XT3/4 Benchmark 5 and 6 on Cray XT3/4 |
NEMO 1-D scaling to 23,000 cores Scaling on 6 HPC Platforms Benchmark 5 on six different HPC resources |
NEMO 3-D scaling to 8,192 cores Scaling on 2 HPC Platforms Strong scaling of a constant problem size (8 million atoms) on 2 different HPC platforms. Solid / dashed lines correspond to a stored / recomputed Hamiltonian matrix. The largest number of cores available were 8,192 on Cray XT3/4 and IBM B/G. |
NEMO 3-D scaling to 8,192 cores Scaling on 6 HPC Platforms Strong scaling of a constant problem size (8 million atoms) on 6 different HPC platforms. Solid / dashed lines correspond to a stored / recomputed Hamiltonian matrix. The largest number of cores available were 8,192 on Cray XT3/4 and IBM B/G. |
NEMO 3-D scaling to 8,192 cores Scaling on RPI BG/L Strong (constant total problem size, diagonal dashed lines) and weak (constant number of atoms per core, horizontal solid lines) on RPI BG/L in recomputing mode. Excellent performance is evident for large enough problem sizes |