[hpsdr] Announcement of a CudaSharpDSP package for HPSDR: doing parallel DSP processing on your GPU

[Hermann]

On Tue, May 18, 2010 at 1:50 AM, Jeremy McDermond
<mcdermj at xenotropic.com> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Thanks for your continued updates Hermann.  I'm anxious to have a chance to take a look at
> some of your work.  Looking forward to the continued progress on CudaSharpDSP.
> Please make sure to continue to keep us in the loop!


Dear All,

this is just a short update on some progress I made on the
CudaSharpDSP implementation. Some two or three weeks ago I got stuck
in a problem which seems to be solved now. I encountered some truly
periodic audio distortions (crackle and clicks) when running the DSP
chain over the graphics adapter, little ones at 48 kHz sample rate,
and bigger ones at 192 kHz. This was very dissatisfying, and I tried
to find out where these distortions came from. A long time I was
looking at the USB interface,  but now it seems I found the reason.

To implement my Cuda stuff I was using a freely available CSharp
wrapper, called CUDA.NET. Though its free, it is not open source. I
was using this wrapper library all the time, because it was very easy
to implement and interface my GPU. Last week I started implementing my
own dll (using P/Invoke and using only blittable types), and two days
ago I finished a first version.

I learned again the hard way, that doing things by yourself is often
better...  ;-)

Now it is the first time that I really see a benefit of doing DSP on
the GPU: with 192 kHz and 8k inbuffer and 2k outbuffer sizes, I have a
perfectly clean audio, and the CPU utilization is nearly the same at
all sample rates (around 10% on an Intel C2D E8400), meaning that I
now can see a true relief of CPU usage.

I will finish a first version now (for 32 and 64 Bit Win-OSes, using
libusb0 for Ozy I), such that everyone can test if she/he wants!

Vy 73,
Hermann

DL3HVH