Docstoc

cocoa-final

Document Sample
cocoa-final Powered By Docstoc
					        COCOA

        MAY 31, 2001
        김경임, 박성호




COCOA        (1/19)    Real Time Systems LAB.
Contents
•   Background
•   COCOA Overview
•   System Architecture
•   Key Technologies
•   Application Area
•   Evaluation
•   Conclusion
•   References

COCOA                 (2/19)   Real Time Systems LAB.
Background
• A Thesis in Aerospace engineering, Pennsylvania State
  Univ. by Anirudh Modi, 1999
    – “Unsteady separated flow simulations using a cluster of
      workstations”

• Need to a suitable platform for the efficiency & accuracy
  of PUMA(a parallel flow solver)
    – Resolving several steady solutions
    – A fully three-dimensional unsteady separated flow around
      a sphere

• PUMA : the Parallel Unstructured Maritime Aerodynamics
• Financial support : the Rotorcraft Center of
  Excellence(RCOE) at Penn State

COCOA                         (3/19)            Real Time Systems LAB.
COCOA Overview
• The COst effective COmputing Array(COCOA)
• A Beowulf cluster that have 50 processors
• To bring low cost parallel computing
    – The whole system cost approximately $100,000
      (1998 US dollars)

• Performance
    – the benchmark shows that was almost twice as fast as the
      Penn State IBM SP (older RS/6000-370 nodes)
      supercomputer for this applications



COCOA                        (4/19)            Real Time Systems LAB.
System Architecture
• Computing Node(26 WS-410 Dell W/S )
    –   Dual 400MHz Intel Pentium II Processors w/512K L2 Cache
    –   512MB SDRAM
    –   4GB UW-SCSI2 Disk
    –   3com 3c509B 100Mbits/sec Fast Ethernet Card
    –   32x SCSI CD-ROM Drive
    –   1.44MB FDD
    –   Cables

• In addition,
    –   One Baynetworks 450T 24-way 100Mbits/sec Switch
    –   Two 16-way Monitor/keyboard/mouse Switches
    –   Four 500 kVa APC UPS
    –   For one server : one monitor, keyboard, mouse and 54GB extra
        UW-SCSI2 HDD

COCOA                            (5/19)             Real Time Systems LAB.
System Architecture cont.
• Setting up H/W




COCOA              (6/19)   Real Time Systems LAB.
System Architecture cont.
• Operating System
    – RedHat Linux 5.1

• Software
    – Base packages from RedHat Linux 5.1, Kernel#2.0.36
    – Freeware GNU C/C++ compiler(gcc, pgcc)
    – Fortran77/90 compiler & Debugger by Portland Group
    – Freeware MPI libraries for parallel programming in
      C/C++/Fortran77/90
    – ssh-1.2.26 for secure access
    – DQS v3.0, a queueing system
    – Scientific Visualization Software TECPLOT from Amtec
      Corp.

COCOA                       (7/19)          Real Time Systems LAB.
Key Technologies
• Beowulf Cluster
    – A system which usually consists of one server node, and
      one or more client nodes connected together via Ethernet
      or some other fast network
    – Developed for large scale computing, such as
      aerodynamics, atmosphere, physics, etc.
    – First Developed at 1994 in NASA
    – Low price supercomputing is possible
        • High performance/low price processors
        • High speed network devices available

    – Numerous Beowulf clusters developed
        • Used in various computational science fields

COCOA                            (8/19)              Real Time Systems LAB.
Key Technologies cont.
• DQS (Distributed Queuing System)
    – Developed to experiment batch queuing system
      at the Super-computer Computations Research Institute, Florida
      State Univ.
    – Provide a single coherent allocation and management

• MPI (Message Passing Interface)
    – Standard for parallel programming

• SSH (Secure Shell)
    – Program for logging & executing commands into/on a remote
      machine
    – Provides secure encrypted communication inter-un-trusted hosts
      over an insecure network

COCOA                           (9/19)             Real Time Systems LAB.
Application Area
• Analysis maritime aerodynamics
    – Analysis flows over complex configurations (like ships and
      helicopter fuselages)

    – Use PUMA

    – Details of problem:
      Helicopter can safely land on frigate in the North Sea only 10
      percent of the time in winter




COCOA                             (10/19)             Real Time Systems LAB.
PUMA (Parallel Unstructured Maritime Aerodynamics)
• Program for analysis of internal and external non-
  reacting compressible flows over arbitrarily complex 3D
  geometries

• Written entirely in ANSI C using MPI library for message
  passing
  and hence highly portable giving good performance




COCOA                       (11/19)         Real Time Systems LAB.
PUMA (Parallel Unstructured Maritime Aerodynamics) cont.
• Use domain decomposition
    – Domain decomposition
        • Distribute data across processes, and each process performing
          approximately same operation on the data
        • Problem level parallelism, but loop level (not SIMD)
        • Minimize communications cost
    – Functional decomposition
        • Divides a problem into several distinct tasks that may be executed
          in parallel

• Parallelization in PUMA
    – Each compute node read its own portion of the grid file at
      startup
    – Each compute node generate the flow solution over the given
      grid, parallelly

COCOA                               (12/19)               Real Time Systems LAB.
PUMA (Parallel Unstructured Maritime Aerodynamics) cont.




COCOA                     (13/19)        Real Time Systems LAB.
PUMA (Parallel Unstructured Maritime Aerodynamics) cont.
• Modifications to PUMA
    – Modify PUMA to read several
      hundred lines at a time and
      broadcasting the combined
      data to every processor
      using a reasonably sized
      buffer

    – Modify MPI to combine
      several small messages into
      one before starting
      communication
                                          Mbits/sec vs Packet size on COCOA
                                               for MPI_Send/Recv test



COCOA                           (14/19)                 Real Time Systems LAB.
PUMA (Parallel Unstructured Maritime Aerodynamics) cont.




                   Improvement in PUMA performance
          after combining several small MPI messages into one

COCOA                          (15/19)              Real Time Systems LAB.
Evaluation




 Total Mflops vs Number of Processors        Speed-up vs Number of Processors
     on COCOA for PUMA test case               on COCOA for PUMA test case


COCOA                              (16/19)                 Real Time Systems LAB.
Evaluation           cont.




                NAS Parallel Benchmark on COCOA:
        comparison with other machines for Class “C” LU test

COCOA                         (17/19)              Real Time Systems LAB.
Conclusion
• Beowulf class supercomputer (PC, Linux, MPI, DQS, SSH)

• Cost effective supercomputer for numerical simulations
    – Almost twice as fast compared to the Penn State IBM-SP supercomputer,
      for our production codes including PUMA,
      given the same number of processors,
      while being built at a fraction of the cost ($100,000(1998 US dollars)).

• Be suitable for only numerical simulation part (weather, fluid...) that
  doesn’t have high communication to computation ratios, because of
  the high communication latency.

• Good scalability with most of the MPI applications used

• The Object, to build Cost effective supercomputer for numerical
  simulations dealt with at Penn State has been fulfilled.


COCOA                               (18/19)              Real Time Systems LAB.
References
•       COCOA : http://cocoa.ihpca.psu.edu

•       NAS Parallel Benchmarks :
        http://science.nas.nasa.gov/Software/NPB

•       Beowulf : http://www.beowulf.org

•       RedHat : http://www.redhat.com

•       MPI : http://www.mcs.anl.gov/mpi
•       DQS : http://www.scri.fsu.edu/~pasko/dqs.html

•       Tons of references…



COCOA                           (19/19)            Real Time Systems LAB.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:3
posted:12/4/2011
language:Korean
pages:19