Many of you probably remember the flurry of posts that I created a few weeks ago about writing a parallel vorbis encoder. Here's what I have been doing since... Someone (I can't remember who offhand -- might have been Greg) mentioned using threads instead of MPI for parallelism on the argument that more people have SMPs than who have (and know how to use) an MPI implementation. Good point. It was fairly striaghtforward to write a multi-threaded encoder, but I found out the hard way that libvorbis.a is not thread safe. :-( Monty tells me that it is on the to-do list, but not currently at the top. Hence, someday a plain-vanilla multi-threaded encoder will be possible. But not today. Bummer. But it got me thinking -- what about mixing MPI and threads? For those of you who don't know anything about MPI, this is a relatively unexplored area, mainly because of the lack of thread-safe MPI implementations (including mine. Oops!). But the more that I thought about it, the more interesting it got, because there's actually a lot of deliciously intracate real-world issues involved. So in between real work (i.e., while waiting for long compiles and the like), I devoted a fair number of cycles to thinking about this. On and off, I've spent the past few weeks writing down many of my thoughts on the topic in a white paper, complete with oodles of pseudocode (somewhat of an oddity, I know, but IMHO, a code snipit = a thousand words). It turned into a generalized white paper (i.e., not specific to vorbis) because of the parallel issues that are raised. However, it *exactly* fits the model of the vorbis library calls (imagine that :-), mainly because vorbis exactly fits a convenient generalized manager/worker model. So to anyone on this list who is interested, I'd appreciate any feedback, comments, suggestions, corrections, etc. Here's the URL where to get the paper: http://www.mpi.nd.edu/~jsquyres/vorbis/ Thanks. {+} Jeff Squyres {+} squyres@cse.nd.edu {+} Perpetual Obsessive Notre Dame Student Craving Utter Madness {+} "I came to ND for 4 years and ended up staying for a decade" --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-dev-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.