On Tue, Jan 24, 2012 at 9:56 AM, ziyang <ziy...@sics.se> wrote: > On 01/19/2012 07:13 PM, Nick Foster wrote: > >> Optimizing an algorithm is a hard and sometimes counterintuitive process. >> You might benchmark the following: >> >> - Gnuradio's atan2 WITHOUT any Volk multiplications (just comment out the >> volk mults in your block) >> - The Volk multiplications WITHOUT Gnuradio's atan2 (just comment out the >> atan2 in your block) >> >> This will let you determine where the bottleneck is. In addition, try >> running over a MUCH larger dataset. The clock resolution at <1ms is not >> very good and the scheduler will have a correspondingly larger effect at >> smaller timescales. >> >> I think you'll find the atan2 part takes vastly longer than the >> multiplications do, and that will be where you have to look for performance >> improvements. >> >> --n >> >> > > Hi Nick, > > I have been doing some tests about the demodulation module. As you said, > the atan2 part takes much longer than the multiplication. So in order to > maximize the performance improvement that volk could bring to the > processing, I took a division and a multiplication out of atan2, and use > volk-ified divider and multiplier instead. Then I run tests using a much > larger dataset. > > But from the test results, I did not observe a performance improvement. In > fact, the average processing time even increase a little bit. So I was > wondering if what I did was not a good way to improve the performance? > > Another issue is that when I ran Cmake to build Gnuradio on E100, it > reported this: > -- Available arches: generic;neon > -- Available machines: generic;neon > -- Did not find liborc and orcc, disabling orc support... > > But from the "opkg list-installed | grep orc" check, both orc and liborc > are installed. Could this lack of orc support be part of the reason why my > implementation did not have a performance improvement? >
Very likely. Make sure that orcc is somewhere that pkgconfig can find it, and make sure its version is > 0.4.10. > > I will appreciate it if you could give me a hand on this. Thanks. > > > Best Regards, > > Terry > > > > >
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