On 03/05/2012 08:10 AM, labarowski wrote: > > I'm using an Ettus N210. I have a simple block diagram in GRC with a cosine > signal source feeding a throttle feeding the usrp sink. All share the
- dont use a throttle, the usrp sink *is* back-pressuring the stream - use this new signal source on my new_blocks or next branch, its much much faster: git://gnuradio.org/jblum.git http://gnuradio.org/cgit/jblum.git/tree/gr-blocks/lib/signal_source.cc?h=new_blocks > samp_rate variable as their sampling rate, which I am trying to get to 50M. > So far, I've been able to achieve up to 25MSPS using Complex int16 as the > wire format with minimal under sampling (A few 'U's are printed to the > terminal at first, but it eventually stabilizes and stops printing Us). I've > been able to get 33.333333MSPS with minimal undersampling using complex > int8. I'm yet to achieve 50MSPS. I have an older computer that was unable to > achieve these sample rates, so I thought it might be my pc. However, this > laptop has a Core i5 M450 @2.4GHz, 4Gb DDR3 and a gigabit Ethernet card > (integrated though). I'm not sure how much power gnuradio requires, but I > feel like this is a fair amount for most applications. 50 Msps is serious amount of data to push through your computer. More than a feeling, even the most serious computers can easily have a bottleneck. I suspect that the gnuradio core signal source cannot sustain 50Msps in 1 thread/1 work function. I've set sudo sysctl > -w net.core.rmem_max=50000000 and sudo sysctl -w net.core.rmem_max=50000000. rmem max cannot help, this on receive wmem_max cant make a difference past 1 megabyte. All the buffering is on the usrp in the transmit direction. wmem_max is simply just large enough so that any packets going out will have the same amount of space on the host to guarantee that send() wont block. > Not sure what else I can do. I thought maybe I could change the decimation > rate, but that's not going to help if I can't change the format over the > wire. Any help is appreciated! Why do you think you cant change the wire format? It sounds like you changed it to sc8 format (above). I prototyping whatever it is you are trying to do at a lower rate, then optimizing it in SIMD routines to get up to 50 Msps on the host. Also, try examples/tx_waveforms with --otw=sc8 --rate=50e6 and experiment with that so you can see if your PC can sustain the rate with minimal load. -Josh _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
