PARALLEL PROCESSING

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PARALLEL PROCESSING

• The NAS Parallel Benchmarks
• Daniel Gross
• Chen Haiout

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NASA (NAS Devision)
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NASA (NAS Devision) Aims

• NASA Advanced Supercomputing Division
• Develop, demonstrate, and deliver innovative
  computing capabilities to enable NASA projects
  and missions
• Demonstrate by the next millennium an
  operational computing system capable of
  simulating, in one to several hours, an entire
  aerospace vehicle system throughout its mission
  and life cycle.

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NPB Introduction

• NAS Parallel Benchmarks suite (NPB) has been used
  widely to evaluate modern parallel systems

• Measure objectively the performance of highly
  parallel computers and to compare their
  performance with that of conventional
  supercomputers

• NPB is based on Fortran 77 and the MPI message
  passing standard

• Consists of eight benchmark problems derived
  from important classes of Arophysics
  applications.

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Benchmark Problems

• EP Embarrassingly Parallel
• IS Integer sort
• CG Conjugate gradient
• MG Multigrid method for Poisson eqn
• FT Spectral method (FFT) for Laplace eqn
• BT ADI Block-Tridiagonal systems
• SP ADI Scalar Pentadiagonal systems
• LU Lower-Upper symmetric Gauss-Seidel

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• The Embarrassingly Parallel Benchmark (EP)
• In this benchmark, 2-dimensional statistics
  are accumulated from a large number of Gaussian
  pseudo-random numbers. This problem requires
  almost no communication, in some sense this
  benchmark provides an estimate of the upper
  achievable limits for floating-point performance
  on a particular system.
• SP benchmark
• It is called the scalar pentadiagonal (SP)
  benchmark. In this benchmark, multiple
  independent systems of non-diagonally dominant,
  scalar pentadiagonal equations are solved. A
  complete solution of the SP requires 400
  iteration.
• MultiGrid (MG) Benchmark
• MG uses a multigrid method to compute the
  solution of the three-dimensional scalar Poisson
  equation.
• This code is a good test of both short and
  long distance highly structured communication.

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• 3-D FFT PDE (FT) Benchmark
• FT contains the computational kernel of a
  three dimensional FFT-based spectral method.
• BT Simulated CFD benchmark
• BT solve systems of equations resulting from
  an approximately factored finite difference
  discretization of the Navier-Stokes equations.

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Class Benchmarks

• Since the 1991 specifications of NPB 1.0,
  computer speed and memory sizes have grown and
  correspondingly so have representative problem
  sizes.

• NPB 1.0 specifies two problem sizes for each
  benchmark class A and a larger class B.
• The class A benchmarks can now be run on a
  moderately
• powerful workstation, and class B benchmarks on
  high-end workstations or small parallel systems.

• To retain the focus on high-end supercomputing,
  we now add a class C for all of the NAS
  benchmarks.

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Weakness Points

• Implementations of the NAS Benchmarks are usually
  highly tuned by computer vendors
• largest problems (class B) no longer reflect the
  largest problems being done on present-day
  supercomputers

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Why 8 Different Benchmarks ?
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Comparing World Wide Clusters

• Loki and Hyglac
• In September 1996 two medium-scale parallel
  systems called Loki and Hyglac were
  installed.
• Each consisted of sixteen Pentium Pro (200
  MHz) PCs with 16 Mbytes of memory and 3.2 and 2.5
  Gbytes of disks per node, respectively. Each
  system was integrated using two fast Ethernet
  NICs in each node.
• Both sites had performed a complex N-body
  gravitational simulation of 2 million particles
  using an advanced tree-code algorithm. Each of
  these systems achieved a sustained performance of
  1.19 Gflops and 1.26 Gflops, respectively. When
  the systems were connected together The same code
  was run again and achieved a sustained capability
  of over 2 Gflops without further optimization of
  the code for this new configuration.

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• Berkeley NOW
• The hardware configuration of the Berkeley NOW
  (Network Of Workstation) system comprise 105 Sun
  Ultra 170 workstations connected by Myricom
  networks. Each node includes 167MHz Ultra 1
  microprocessor with 512 KB cache, 128 MB of RAM,
  two 2.3 GB disk space.

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• Cray T3E
• The Cray T3E-1200 is a scalable shared-memory
  multiprocessor based on the DEC Alpha 21164
  microprocessor. It provides a shared physical
  address space of up to 2048 processors over a 3D
  torus interconnect. Each node of the system
  contains an Alpha 21164 processor each of which
  is capable of 1200 Mflops. The system logic runs
  at 75 MHz, and the processor runs at some
  multiple of this, such as 600 MHz for Cray
  T3E-1200. Torus links provide a raw bandwidth of
  650 MBps in each direction to maintain system
  balance with the faster processors and memory.

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NPB Graph Results
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The Dwarves Hardware

• Old PII at 300MHz processors Will be
• removed soon.
• 8 PIII at 450MHz processors
• 4 PIII at 733MHz processors
• The new machines
• Dual AMD Athlon(tm) MP 2000 _at_
• 1,666MHz. 1GB Memory.

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In The Next 2 Weeks

• Install the NPB 2.2 on the Dwarves cluster
• Run the Benchmark tests on the Dwarves Cluster
• Run tests on several different configurations
  (different number of dwarves)
• Estimate Network Bandwidth and latency.
• Compare the Dwarves cluster performance to
  similar clusters in the world

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Questions will not be answered !!!
GOOD NIGHT