On 02/13/2013 01:36 AM, Per Zetterberg wrote: >> http://code.ettus.com/redmine/ettus/projects/public/wiki/Latency > > This was very interesting. A few questions: > > is "Samples per block" = samples per buffer ? > > How is the old: > dev_addr["recv_buff_size"]=20000; uhd::usrp::multi_usrp::make(dev_addr); > > related to sbp and spp ?
Many of the examples have samples per buffer (spb) which effect the size of the client app's buffers for samples; its not really a concept in UHD. Basically, this size is independent of how packets get fragmented on the wire; because UHD will deal with the fragmentation on both the TX and RX side to fill or read from the users buffer. For example, the samples per buffer in gnuradio changes size from work call to work call. Samples per packet (spp) affects the slicing of the packet framer on the RX chain. This is by default, set so each packet is MTU sized. So SPP can be used to shrink the packet size, mostly for latency reasons. Setting a small recv_frame_size will also work for this purpose; since this frame size basically sets the MTU by setting the internal buffers used with the socket. And therefore, when the frame size is decreased, the spp will automatically be smaller as well to fit into the MTU. You can think of spp as a more fine grained MTU setting because it can be set per streamer rather than once at device init time. The recv_buff_size is unrelated, its just the amount of total buffering a socket can offer. I will have to leave the other questions to Balint. -josh > > If I have a dual-boot machine with two different ubuntu versions. If I tweak > the NIC parameters from one boot - will it change the other as well ? > > Where do I find the code for "responder" ? > What is it doing ? > > I can't read the results for N210, two many lines, I can't see which is > which. Is it reproduced somewhere else? > > Thank you, > Per Zetterberg > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
