Re: [Discuss-gnuradio] GNURadio and CUDA reprised

[Moeller]

On 11.01.2011 23:13, Andrew Hofmaier wrote:
> I've begun to look into accelerating GNURadio applications with Nvidia CUDA 
> GPU's
> and have scanned through the archives of the discussion list.  I had two
> questions on the topic:
>
> 1.  Is the CUDA-GNURadio port done by Martin DvH circa 2008 still
> available and runnable?  All links I've seen are broken.

Is CUDA really suitable? There is a certain overhead in data communications.
CUDA is only useful, if it can compute complex things without communicating.
But a data streaming application needs lots of I/O.
The CPU with SSE is also very fast in things like FFT.
I made some experiments with CUDA, but they were not very successful,
far below the peak FLOPS you get in benchmarks.
But I'm not an experienced programmer ...

> 2.  Much of the results I've seen, both here and elsewhere, suggest that
> CUDA is not typically applicable to general GNURadio applications.  It
> has worked in specific cases, but only where the data throughput
> requirements are very high and the algorithms are extremely

Yes, I had the same experiences. I tried to let CUDA do the one-dimensional FFT.
It was slower than on CPU, had a large communication overhead.
Maybe better with larger FFT sizes, or with 2D FFT, or better programming ...
In contrast, the sample programs were very fast, but also very special
like Fractals computing, Image processing or particle physics.

> these cards for GNURadio applications?  Some of the major relevant
> improvements are the ability to concurrently schedule multiple kernels
> and asynchronously perform memory transfers.

I think important is that the kernels have to compute very much, compared
to data transmission tasks. 1D FFT is not very computing-intensive, related to
data shifting. What kind of algorithm do you want to port to CUDA?