Simple math. A 9000 *byte* packet is 72000 *bits*
At 1.0e9 *bits/sec* that’s a latency of 720usec Sent from my iPhone > On Dec 30, 2020, at 8:55 AM, Jorge Arroyo Giganto via USRP-users > <usrp-users@lists.ettus.com> wrote: > > > Hi EJ, > > Yes, I tried replacing the DMA FIFO with a normal FIFO and the latency got a > bit worse and more irregular (I'm guessing that's due to not smoothing that > burstiness in the Ethernet interface with the DMA FIFO you mentioned). > > I have just tried your graph suggestion (Host -> FFT -> FIFO -> Host) and the > latency looks about the same but in the FFT block instead. Also I had to use > packets with spp=256 in the tx streamer in order to match the spp that the > FFT block accepts or I would get an error when building the streamer. Maybe > making the FFT block somehow be able to accept bigger packets would decrease > the latency? > > About the theoretical latency for a packet of 8192 bytes you mention, > shouldn't it be 8192*4 bytes assuming that each sample is a sc16 (2 bytes for > the real part and 2 bytes for the imaginary part of each sample)? Then this > latency I am experiencing would make more sense? > > Thank you so much for your feedback, I will also keep in mind your comment > about the way I am using RFNoC. > > Best regards, > > Jorge > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
