[vorbis-dev] Parallelism

[Jeff Squyres]

On Wed, 16 Aug 2000, Segher Boessenkool wrote:

> > > Is the coding required for parallelism detrimental in for single-CPU
> > > uses?
>
> He means if the 'normal' code gets any slower.
> 
> I would suggest making separate source files for 'multi' encoding,
> calling the correct 'single' routines. Probably the program flow will
> be different from the 'single' encoder.

It depends on how it's coded.  Good software engineering comes into play
here, too -- there's no use in duplicating code.

Parallel bladeenc code uses the same core code for both parallel and
single CPU encoding.  That is, the MP3 encoding process is already
centered around taking a chunk of input data and turning it into output
frames.  Hence, it was already neatly broken up into discete parts that
don't matter if they all run on the same CPU or not.

The parallel code just adds some additional framing as well as the
transmission/receipt of the input/output data to remote nodes.  You can
think of it as an extra loop around the core encoding code.

Whether or not this applies to vorbis is a question that I cannot answer
-- I don't know the algorithms, nor do I know the code.  Hence, my first
post to this list.  :-)

{+} Jeff Squyres
{+} squyres at 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"

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