Re: tlug: Clustering Linux Boxes

["Stephen J. Turnbull" <turnbull@example.com>]

>>>>> "Chris" == Christopher Sekiya <wileyc@example.com> writes:

    Chris> On Mon, 24 May 1999, Austin Kurahone wrote:

    >> Now the question that I have is that will making a cluster(eg:
    >> Avalon with Extreme Linux) give me performace advantages for
    >> all my programs, or do they need to be specially coded to take
    >> advantage of the cluster.

    Chris> They need to be specially coded.

Not if you distribute processes rather than threads.

Also, there are (eg) FORTRAN compilers which will automatically take
advantage of a certain amount of parallelism that is inherent in
things like do loops.  I doubt there are C compilers that do this (at
all, let alone free code), but you could probably hack an optimization
stage into GNU C/C++.  What one person could do by September will
probably suck, but it would be too cool a hack for people to let
alone.  It would not suck any more on October 1 ;-)

And of course some programs will surely run more slowly in parallel ;-)

    >> If they need to be specially programed, what is the feasibility
    >> of coding/implementing a transarent layer(a module maybe) that
    >> will allow the Linux kernel to automatically distribute the
    >> separate threads/tasks to the various nodes in the cluster???

    Chris> This is a userspace issue (nothing special needs to be done
    Chris> to a stock kernel to do clustering[1]).  Check out MPICH
    Chris> and/or PVM.

If you're using a distribution which allows searching package space
(eg debian) search on `mpi' and `pvm'; there are several packages in
Debian already (SPAlina or something like that is one) taking
advantage of them.  Since the interfaces are different the packages
get a -mpi or -pvm suffix.

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