On Wed, Jan 12, 2011 at 3:39 PM, Marcus D. Leech <mle...@ripnet.com> wrote: >> On Jan 12, 2011, at 2:56 PM, Moeller wrote: >> The "very large FIR filters" was a thought, as an example of an operation >> that might benefit from a GPU at least when using OpenCL (or CUDA). I >> haven't done testing yet to know if a GPU can do better than a CPU using >> vector instructions ... but I'm getting there. If/when I do get there, I'll >> post my results& thoughts. >> > Very large FFT filters is also something worth looking into. GPUs have been > considered for real-time coherent de-dispersion of radio astronomy > data streams for pulsar detection. De-dispersion over large bandwidths at > low frequencies requires ferociously-large FFT filters, but in > order to make this a viable proposition, you likely have to do the > detection and folding on the GPU as well, producing an output data > stream that is several orders of magnitude smaller/slower than the input > stream. I read a paper on this, (for the specific case of > pulsar detection with real-time coherent de-dispersion), and they concluded > that it's doable, on the higher end GPUs, provided that > you do detection and folding on the GPU as well, otherwise you lose due to > transfer overhead. > > It seems like the only time you ever really "win" with a GPU-based solution > is when you have to suck in large amounts of data, > pound on it furiously, and then produce an output stream that's relatively > modest. Otherwise, you seem to lose due to data-transfer > overhead. > -- > Marcus Leech > Principal Investigator > Shirleys Bay Radio Astronomy Consortium > http://www.sbrac.org
>From my experiments, I don't thinks its a A _and_ B situation. I think if you have either A) a large amount of data _OR_ B) have to pound on it furiously, you get a win. Most filters needed for normal comms is not enough data or computation, but doing, maybe, a turbo product code or some heavy compute task with normal amounts of data (say, blocks of around 8k samples), you can get a win. Tom _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
