Thanks Neel, I've already played with the following values:
- recv_frame_size - num_recv_frames - send_frame_size - num_send_frames in the /b200_impl.cpp file , but I still get the same number of late packets in latency_test. On Wed, Jul 4, 2018 at 6:57 AM Neel Pandeya <neel.pand...@ettus.com> wrote: > This system is an older low-power system. It's an Intel Core i5 i5-2520M > at 2.50 GHz, and is about six or seven years old. > > You should definitely do some of the performance tuning steps, such as > setting the R/W socket buffer sizes, and setting the CPU governors to > "performance" mode, etc. > > https://files.ettus.com/manual/page_transport.html#transport_udp_sockbufs > > To reduce latency, I would suggest that you upgrade to a newer > more-powerful laptop. > > Also make sure that you are not seeing any underruns or overruns as your > run any UHD programs. You should run "benchmark_rate" at the Tx and Rx > sampling rates that your application requires to verify whether your system > can reliably sustain those rates. The link below has some information about > performance errors ("O", "U", "D", "S", "L"). > > > https://files.ettus.com/manual/page_usrp_x3x0_config.html#x3x0cfg_hosthw_troubleshooting > > --Neel Pandeya > > > > > On 3 July 2018 at 20:14, Wael Ali <wa2el....@gmail.com> wrote: > >> Dear Marcus and Neel >> I'm really appreciate your reply >> I'm using Dell Latitude E6320, USB 2 >> the output of "sudu lshw -html" is attached >> I didn't have any kind of tunning except of real-time scheduling of the >> uhd >> >> >> On Wed, Jul 4, 2018 at 2:28 AM Neel Pandeya <neel.pand...@ettus.com> >> wrote: >> >>> Your latency will be made up of the delay caused by the USB bus itself, >>> which you can't do much about, and the processing delay in your host >>> computer. >>> >>> Have you profiled your application? >>> >>> Have you done any performance tuning on your system (CPU governors, R/W >>> socket buffer sizes, etc.) >>> >>> What kind of hardware do you have? Could you attach the output of "sudo >>> lshw -html"? >>> >>> --Neel Pandeya >>> >>> >>> >>> >>> On 3 July 2018 at 14:57, Marcus D. Leech via USRP-users < >>> usrp-users@lists.ettus.com> wrote: >>> >>>> On 07/03/2018 05:10 PM, Wael Ali via USRP-users wrote: >>>> >>>> Dear all, >>>> please help me with this issue, >>>> >>>> while I'm testing latency between uhd and b205mini with latency_test >>>> file provided with uhd examples gives me the following >>>> >>>> Summary (test1) >>>> ================ >>>> Number of runs: 1000 >>>> RTT value tested: 1 ms >>>> ACKs received: 302/1000 >>>> Underruns: 0 >>>> Late packets: 698 >>>> Other errors: 0 >>>> >>>> Summary (test2) >>>> ================ >>>> Number of runs: 1000 >>>> RTT value tested: 2 ms >>>> ACKs received: 784/1000 >>>> Underruns: 0 >>>> Late packets: 216 >>>> Other errors: 0 >>>> >>>> >>>> >>>> >>>> *I need rrt<= 1ms, and I need to know, how to reduce the latency >>>> between uhd and the device? Is this a hardware issue (related to usb port)? >>>> * >>>> I've already tried to use low latency linux kernel, but the results >>>> were almost the same. >>>> >>>> OS: Ubuntu 16.04 >>>> Kernel: 4.13.0-36-generic >>>> UHD: 3.12.0.HEAD-0-gec786351 >>>> libusb: 0.1.12 >>>> >>>> Thanks is advance >>>> Wael Ali >>>> >>>> What type of computer? Are you using USB3.0, or USB2.0? >>>> >>>> >>>> >>>> _______________________________________________ >>>> USRP-users mailing list >>>> USRP-users@lists.ettus.com >>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>>> >>>> >>> >
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