Those values can be set through the device string on the command line with the "--args" option.
You would be better-served by using a more powerful laptop, one that uses USB 3.0, as your current laptop only supports USB 2.0. --Neel Pandeya On 4 July 2018 at 01:35, Wael Ali <wa2el....@gmail.com> wrote: > 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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