Reply-to: gcf@npac.syr.edu To: gannon@iuvax.cs.indiana.edu, "George K. Thiruvathukal" Subject: I assume this will be incorporated into report Date: Thu, 24 Sep 1998 11:52:51 -0400 From: Geoffrey Fox and no actions required by me? Geoffrey Fox gcf@npac.syr.edu, http://www.npac.syr.edu Director of NPAC and Professor of Physics and Computer Science Phone 3154432163 (Npac central 3154431723) Fax 3154434741 ------- Forwarded Message Date: Tue, 08 Sep 1998 15:22:17 +0100 From: Martin Westhead To: javagrandeforum@npac.syr.edu Subject: Concurrency working group notes This is a multi-part message in MIME format. - --------------454022086C2F Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi Folks, I'm sorry these have been so long in coming. Attached is an HTML file of the notes I took during the forum working group meetin at the beginning of the month. They amount to basically a copy of what Dennis wrote on the board. I believe George took a separate note of actions although there are some peoples names down in this next to areas of responsibility. In terms of the benchmarking EPCC is going to provide some effort to make a start on this before Supercomputing. We'll be contacting those of you with you're names against benchmarks soon. Thanks, Martin - --------------454022086C2F Content-Type: text/html; charset=iso-8859-1; name="Applications and Concurrency .html" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline; filename="Applications and Concurrency.html" Content-Base: "file:///H|/martinwe/Java%20Grande/Appl ications%20and%20Concurrency.html" Applications and Concurrency

Applications and Con= currency

Chair: Dennis Gannon

Notes taken by: Martin Westhead

 

These notes were taken at the applications and concurrency working gro= up of the Java Grande Forum on the 7th-8th of Augus= t 1998. A separate action list was taken by George K Thiruvathukal.

RMI performance issues

  1. RMI

Issues

    • Support for non-TCP & HP protocols (Memory, ATM, Myranet, FM=85= ,IPC) [API]
    • Connection management (too frequently opening & closing connectio= ns)[IMP]
    • Class compatibility [IMP]
    • Resource consumption (implementation issue)[IMP]
    • Scheduling conflicts [IMP]

 

Solutions

    • Possible soln GMI a new object

 

  1. Serialization

 

Issues

  • Too much type information
  • Efficient support for non-recursive (flat) structures [API]
  • Buffer size control [IMP]
  • Too many copies [IMP]
  • Serialization of float & double goes through the JNI
  • Serialization of objects with multiple primitive instance variables i= s inefficient because it requires individual expensive calls for each var= iable

Solutions

  • Serialization API
  • Caching and connection persistence
  • Aggregate serialization of objects with multiple primitive instance v= ariables

VM issues

  • Process/Threads: Affinity/co-scheduling
  • Memory management :
    • How does the VM optimize deep memory hierarchies?
    • Large objects? Limitations
    • Large number of objects
  • Staging large objects (3d graphics problem)
  • Scalable I/O

Benchmarks (Martin W= esthead)

Aim to find programs that will stress the VM in ways that are importan= t to Grande application

(Check out netlib benchmarks. Talk to Java 3D)

 

Applications

    • Monte Carlo (NCSA + EPCC: financial)
    • Image analysis/Radio astronomy (NCSA)
    • Gravitational N-body Simulation
    • Computational Fluid Dynamics (Syracuse)
    • Geophysics (Michael)
    • Discrete Event Simulation (INRIA + EPCC)

Kernels

    • Spec Java Kernels
    • Mpeg3 audio decoder
    • Javac
    • Jess
    • Ray tracing
    • Sorting =96 George
    • Threads =96 synchronization, scalability, threads v. runable =96 Denn= is
    • RMI =96 Michael
    • Serialization - Michael
    • I/O =96 Dan Reed
    • Memory management =96 object size, object number, garbage collection = - - PM
    • Sun benchmarks?
    • Low level arithmetics =96 Numerics Group
    • Linpack - NG
    • Jama =96 NG

Comparisons (Email from Vladimir)

    • JVMs
    • Compilers v. JVMs
    • Language comparisons

Seamless comp (PM)

Define a simple common interface: java.lang.org.grande.seamless

    • Relationship to other technologies:
    • Unicore
    • Globus
    • Legion
    • Condor
    • Sweb
    • Websubmit
    • Issues
    • Authentication
    • Resource discovery (metadata)
    • Resource allocation (Grande cache)
    • Accounting
    • Resource and job Scheduling
    • Job monitoring
    • Code/Data-filesystem
    • Connected to resource discovery service (JINI)
    • Action will involve an examination of the various technologies in ord= er to refine issue list

 

Other parallel issues

    • MPI
    • Pure bindings
      • Interface style issue
      • Not feasible or sensible to do whole MPI
      • Request for Proposals for a deprecated MPI interface
      • Issues with heterogeneous language interaction
    • Extended MPI flavour
      • JMPI
      • Difficult to reach a consensus
    • Could be built on top of a pure MPI
    • Too early to produce a specification but encourage experimentation in= this area
    • Object model : value semantic in proc calls, remote reference managem= ent, problems for large objects [API] =96 Controversial and moved from= RMI section
    • Threads issues
 - --------------454022086C2F-- ------- End of Forwarded Message