On Fri, 2009-06-26 at 23:30 -0700, Bill Broadley wrote: > Keep in mind that when you say broadcast that many (not all) MPI > implementations do not do a true network layer broadcast... and that > in most > situations network uplinks are distinct from the downlinks (except for > the > ACKs). > > If all clients need all input files you can achieve good performance > by either > using a bit torrent approach (send 1/N of the file to each of N > clients then > have them re-share it), or even just a simple chain. Head -> node A > -> node B > -> node C. This works better than you might think since Node A can > start > uploading immediately and the upload bandwidth doesn't compete with > the > download bandwidth (well not much usually).
What you are recommending here is for Amjad to re-implement MPI_Broadcast() in his code which is something I would consider a very bad idea. The collectives are a part of MPI for a reason, it's a lot easier for the library to know about your machine than it is for you to know about it, having users re-code parts of the MPI library inside their application is both a waste of programmers time and is also likely to make the application run slower. Yours, Ashley Pittman. -- Ashley Pittman, Bath, UK. Padb - A parallel job inspection tool for cluster computing http://padb.pittman.org.uk _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
