[asterisk-dev] nVidia Cuda

Wai Wu wkwu at calltrol.com
Mon Mar 5 08:18:11 MST 2007

I just have a very difficult getting a hold on the G729 source code. For
now, I am just starting with some basic stuff like echo cancelation, and

-----Original Message-----
From: asterisk-dev-bounces at lists.digium.com
[mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of CA DM
Sent: Monday, March 05, 2007 3:14 AM
To: email at mattruby.com; Asterisk Developers Mailing List
Subject: Re: [asterisk-dev] nVidia Cuda

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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