[Flac-dev] Flac-dev Digest, Vol 45, Issue 2

[Brian Willoughby]

There's a problem with Intel's TBB package: It won't run on PowerPC  
or other processors.


On May 6, 2008, at 21:41, Frederick Akalin wrote:

On Tue, May 6, 2008 at 4:52 PM, Christopher Peplin
<chris.peplin at rhubarbtech.com> wrote:
> Along the same line as Frederick, myself and another university  
> student were able to implement a multi threaded FLAC
>  encoder, but using Intel's Threading Building Blocks (TBB)  
> package. We saw similar near-linear speedup.

Great!  Your approach is better in that it bounds the memory usage of
the encoding, which is nice, and it also is amenable to streaming; a
similar pipelined approach would probably be best for the production
encoder.  Using mmap() for the input file like I did might simplify
your first pipeline stage and reduce the number of modifications you
need to make to libFLAC (as well as improve I/O performance) at the
cost of having to write callbacks yourself.  Using aio for the output,
too, might improve performance but it might not be worth the extra
trickiness.

> I agree with Frederick in that the existing encoding API was  
> obviously designed for serial execution, and any internal threading  
> support would be messy. We had to come up with quite a few tricks  
> to modify as little of libFLAC as possible.

It looks like implementing parallel-friendly APIs is indeed the
logical next step.

-- 
Frederick Akalin
http://www.akalin.cx
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