any help? 2009/7/2 Yu-Hua Yang <flagm...@gmail.com>
> > > ---------- Forwarded message ---------- > From: Yu-Hua Yang <flagm...@gmail.com> > Date: 2009/7/2 > Subject: Re: [Discuss-gnuradio] CUDA-Enabled GNURadio gr_benchmark10 > possible improvements > To: Martin DvH <gnuradiom...@olifantasia.com> > Cc: discuss-gnuradio <discuss-gnuradio@gnu.org> > > > Thanks Martin, for your generous effort to help me. > > It appears only one time so I think I am in the clear. > > I decided to abandon and comment out all the cuda.multiply_const_ff > function calls and concentrate on cuda.fir_filter_fff as suggested. Things I > got questions/concerns > > 1. I increased output_multiple by doing "options.output_multiple = xxx" and > this has no effect on the computing time of either CUDA or CPU. Did I do > something wrong? > 2. I increased the taps by doing "taps = range(1,256)" and also increasing > number of blocks of fir_filter in the code and voila, I am now able to get > CUDA to be faster than just CPU. However, if I implement something like > "taps = range(1,512)" the CUDA part would be extremely slow (~20 seconds) > while the CPU is still cool (~ 2 sec). Why? But this maybe related to what > you were saying about max number of taps...although why is CPU able to still > compute? > 3. I had to increase the number of fir_filter blocks to 14 blocks before I > can start seeing CUDA out-perform CPU. Experimentally its fine, I achieved > my objective, but how is this "increased computation" justified in a normal > GNURadio operation? I mean, when would a normal GNURadio operation require a > chain of 14 fir_filters? I guess this is going beyond just "benchmarking" > and asking where else can I take advantage of CUDA's computation power in > GNURadio in a "normal" operation? > 4. Looking at cuda_fir_fff_7_kernel, which I believe is the core of > cuda_fir_filter, it seems you are using shared memory right? Just making > sure we are not using global or local memory which would disastrously slow > down the CUDA computations. > > >
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