[asterisk-dev] nVidia Cuda

CA DM cadm at tiscali.it
Mon Mar 5 01:13:59 MST 2007

You don't need to port the entire codec code to a GPU. GPU aren't 
good general purpose processors, such as CPU aren't good stream processors.

Code need to be cleaverly distributed across the specific abilities 
of CPU and GPU (eg.: decoding and unpacking the data stream is a task 
suited for the CPU, like data block transformations are for the GPU) 
if you want to get the most from both.

At 20.38 04/03/2007, you wrote:
>         Compression algorithms have generally not been ported to 
> GPUs like the
>G80. They're usually more logic and branch oriented than just brute
>force multiply-accumulates that GPUs specialize in. I also haven't seen
>any of the popular Asterisk codecs, like G.729 or GSM, ported to any
>GPU. Is there a source for codecs ported to GPUs? Or any research
>showing a good approach?
>On Sun, 2007-03-04 at 10:12 -0700, asterisk-dev-request at lists.digium.com
> > Date: Sat, 03 Mar 2007 22:05:19 -0500
> > From: Wai Wu <wkwu at calltrol.com>
> > Subject: [asterisk-dev] nVidia Cuda
> > To: asterisk-dev at lists.digium.com
> > Message-ID: <B0430B20D208514CB2AFF57E81645C3101B970 at k3-1.Calltrol.com>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > Hi devs,
> >
> > Has any one looked into cuda to see if cpu intensive part of
> > asterisk(like codecs and conference) can be moved to the G80
> > processor? I found that the GF8800 cards are very inexpensive (around
> > 400 USDs per). I have ported some of our financial applications to
> > this board and found almost 10x performance improvement over the 3GHz
> > C2D host processor. I would like to do the same for asterisk.
> >
> > To start. I have been looking into the asterisk code and have no crew
> > how it is structured except the addon applications. Here I have two
> > questions.
> >
> > 1) Is each channel use their own thread if a codec is used?
> > 2) Which part of the asterisk code actually makes the call to the
> > necessary codec? I notice in the applications. They save and set the
> > frame format, then read from the channel. So I trace the read
> > function, but all it does is reading from a file descriptor. So I need
> > some help here.
>(C) Matthew Rubenstein
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