[asterisk-dev] DSP pci board.

[Andrew Pollack]

Agreed -- fourier transforms are expensive, but on modern multithreaded --
and multicore even -- processing systems that run at multiple gigahertz,
are doing so many instructions per second that it could easily be more of a
bottle neck getting the windows in and out of of the external processor
than just processing them would be.

---
Andrew Pollack
Northern Collaborative Technologies
207-221-2547


asterisk-dev-bounces at lists.digium.com wrote on 03/22/2006 05:40:29 PM:

>

> On 3/22/06, Wai Wu <wwu at calltrol.com> wrote:
>
>
>
> I was thinking just patching,  say "codec_gsm.c"
> GSM is a codec that was optimized for early mips processors back in
> the early 90s, and more or less flies on a modern processor. (the
> only way I can think of to make it go faster on a modern
> architecture would be to do multiple channels of gsm
> encodings/decodings in the same pass)
>
> I would argue that the only  codecs worth patching for a DSP would
> be the higher overhead speex and  g72x  codecs.
>
> Even then the price of the virt->phys kernel transition required for
> the userspace asterisk to talk to a kernelspace dsp is probably way
> too high. A good place for a dsp is in a pots card like the digium
> T1 cards, where the interface to the data can run purely in kernel space.

>
> -----Original Message-----
> From: asterisk-dev-bounces at lists.digium.com
> [mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of BJ Weschke
> Sent: Wednesday, March 22, 2006 5:07 PM
> To: Asterisk Developers Mailing List
> Subject: Re: [asterisk-dev] DSP pci board.
>
> On 3/22/06, Wai Wu <wwu at calltrol.com> wrote:
> >
> > Hi all,
> >
> > Has been poking through the * source code a bit and trying to identify
>
> > the most CPU demanding piece of code. Is trans-coding the most CPU
> > demanding? I happen to have access to a DSP pci board. If I can move
> > the encoder/decoder off the host processor onto the DSP board, will I
> > get a decent performance boost for an * PSTN gateway for VoIP phones
> > (assuming all VoIP phones are using say g732, g729 or gsm)?
> > _______________________________________________
>
>
> You will get a performance increase, but then you'd also have to write
> Asterisk drivers for it.
>
>
> --
> Bird's The Word Technologies, Inc.
> http://www.btwtech.com/
> _______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --
>
> asterisk-dev mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-dev
> _______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --
>
> asterisk-dev mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-dev
>
>
>
> --
> Mike Taht
> PostCards From the Bleeding Edge
> http://the-edge.blogspot.com
_______________________________________________
> --Bandwidth and Colocation provided by Easynews.com --
>
> asterisk-dev mailing list
> To UNSUBSCRIBE or update options visit:
>    http://lists.digium.com/mailman/listinfo/asterisk-dev