[Discuss-gnuradio] CUDA-Enabled GNURadio gr_benchmark10 possible improvements

[Yu-Hua Yang]

Hi

Has anyone able to successfully improve CUDA-Enabled GNURadio's performance? At the moment I am very new at this stuff so I am just looking at Martin's code without any really solid understanding. I know that the gr_benchmark10_test.py performance is slow computing on GPU due to the over-head memory calls to and from the CPU and GPU, and that if more compution/work is done per call, the GPU can out-perform the CPU. However looking at the gr_benchmark10 code, it seems that very trivial computations are being done to compare the CPU and GPU. Specifically:

> testblock3= cuda.fir_filter_fff(1,taps)
> testblock4= cuda.multiply_const_ff(1.0)
> testblock5= cuda.multiply_const_ff(1.0)
> testblock6= cuda.multiply_const_ff(1.0)

I attempted to "increase" the GPU performance by inserting very large floating point numbers as parameters to cuda.multiply_const_ff and also messing around taps which is declared by:

taps=range(1,64,1)

But in doing so, I assume that I am passing in "more work" to be done so the GPU should be faster, but it is not. the CPU still takes fractions of a second to complete (with large floating points) while the GPU takes a little over 1 second.

- Following this thread:http://lists.gnu.org/archive/html/discuss-gnuradio/2009-01/msg00378.html
 I would like to approach the problem by increasing computation intensity, thats why I am changing the benchmark parameters, but it doesnt seem to work, Am I approaching this correctly?

- From this thread: http://lists.gnu.org/archive/html/discuss-gnuradio/2008-11/msg00292.html

If I benchmark a single block with a big output_multiple then I do see

performance increases.

How do I do the above? How have the experts (Martin, Achilleas) been able to tweak the performance of CUDA-Enabled GNURadio to show that GPU computing can indeed be faster?

- Is there anyway to measure the time the memory calls to and from CPU and CUDA? This way we can know what exactly is the overhead.

Please help!!