On Wed, 19 Mar 2008 21:33:11 +0100 Erik Trulsson <[EMAIL PROTECTED]> wrote: > A system that is written to work in a clustered environment can fairly > easily be moved to run on an SMP machine, but it will do a lot of work > that is not necessary under SMP and thus not make very good use of the > hardware. > Moving from SMP to cluster is more difficult. One can emulate the missing > hardware support in software, but this has a very high overhead. Or one > can rewrite the software completely, which is a lot of work.
One way to think of such is that cluster software will typically consist of lots of processes talking to each other over sockets whereas SMP software will typically consist of one process with threads talking to each other through shared memory locations. On an SMP system the cluster software could be rewritten to use shared memory and hence improve performance. Likewise, moving the SMP program into a cluster environment means you have to replace shared objects with proxies that copy things around and coordinate actions. At least one concurrent software development system (Bertrand Meyer's SCOOP) is set up so the developer doesn't worry about those things; the location and communications channels of the objects in the program is specified at launch time. <mike -- Mike Meyer <[EMAIL PROTECTED]> http://www.mired.org/consulting.html Independent Network/Unix/Perforce consultant, email for more information. _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
