Unfortunately, I have to stick to the i3 for now, since it is the only PC here with an PCI-E slot for the 10 Gig ethernet.
Anyway, I have installed UHD_3.14.1 from the Ettus repository and compiled gnuradio-3.8.0.0-rc2. Now things look a bit better. A flowchart with a Signal Source, an UHD USRP Sink, an UHD USRP source and a QT GUI Sink works up to 66.7 MSPS duplex (the X310 can only do samples rates that are integer fractions of 200 MHz). With a constant source, 100 MSPS are possible. With sender-only or receiver-only flowcharts, I can achieve 200 MSPS. Not so bad. Best regards, Erik -- ???????????????????????????????????????? Supracon AG Dr. Erik Heinz An der Lehmgrube 11 07751 Jena Tel.: +49 3641 2328-165 Fax: +49 3641 2328-109 Internet: http://www.supracon.com ???????????????????????????????????????? Handelsregister: Amtsgericht Gera HRB 208970 Umsatzsteuer-Id.: DE 216 111 685 Kaufm. Vorstand: Matthias Meyer Vorsitz Aufsichtsrat: Prof. Dr. Michael Siegel ________________________________ Von: USRP-users <usrp-users-boun...@lists.ettus.com> im Auftrag von Marcus D. Leech via USRP-users <usrp-users@lists.ettus.com> Gesendet: Montag, 29. Juli 2019 17:36 An: usrp-users@lists.ettus.com Betreff: Re: [USRP-users] X310 slow with gnuradio On 07/29/2019 07:30 AM, Erik Heinz via USRP-users wrote: Hi, I am getting lots of underflow errors when sending with gnuradio to an X310 at sampling rates of 50 MSps and higher. The flowchart is as simple as possible: a signal source and a "UHD: USRP Sink" block. When sending and receiving at the same time, the performance is even worse. The X310 is connected to the PC by 10G ethernet. Using the UHD example programs benchmark_rate, tx_waveforms, txrx_loopback_to_file etc., a sampling rate of 200 MSps full duplex is no problem at all. So it is not a problem of the UHD driver and the network setup should be OK as well. The processor is an Intel core i3-7100 @3.9GHz. A gnuradio flowchart with a signal source, a throttle block and a file sink works at 50 MSps sampling rate and more, so the processor speed should not be a problem either. The gnuradio version is 3.7.11 which is the one currently distributed for Ubuntu buster. Any ideas? Could an update to a more recent gnuradio version help? Best regards, Erik The file-sink version is NOT a good comparison, since the filesystem doesn't need samples to "arrive on time", so there's no concept of an "under-run". The signal source in Gnu Radio is not super-speedy, particularly if it's generating a sin or cos function. Also, the core i3-7100, despite the high clock rate, doesn't perform nearly as well as the i7 series, which is what most people choose for doing serious high-speed DSP work with Gnu Radio.
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