Have looked into the benchmark rate utility (uhd/host/build/examples/) which shows dropouts at any sample rate above 2MSPS. Have also run the same thing from a PC laptop running ubuntu 20.04 in a virtual machine with the same gnuradio (3.8), same uhd (4.0.0) and same gr-ettus (RFNoC 4). It also flags dropouts consistently at any sample rate above 2MSPS. The fpga image for the X310 was downloaded and installed according to the instructions in the hardware manual (https://files.ettus.com/manual/page_usrp_x3x0.html). It appears to us that the issue lies with something to do with the X310 or software that is communicating with it, or the fpga image.
Is there any setup item we can change to get net traffic without dropouts? Will there be a problem if we don’t drain data from the other receives at the same time since there are four of them? Thanks Jonathan Pratt From: Marcus D. Leech <[email protected]> Sent: Tuesday, 30 November 2021 10:35 AM To: [email protected] Subject: [USRP-users] Re: USRP streaming data performance WARNING: This message has originated from an untrusted source. Be mindful of attachments and embedded links. On 2021-11-29 18:22, Jonathan Pratt wrote: We are looking to develop a standalone sdr platform connecting an nVidia Jetson AGX Xavier to a USRP X310. The X310 has two dual receiver boards installed but we are only trying to stream data from one core at this time. The Xavier is an octacore ARM platform with all cores enabled and running close to 1.5GHz. The connection between the two devices is via ethernet running at 1Gbit. The xavier has a x16 PCIe interface connector and we are using a NIC with 1Gbps SFP module – we intend to run the link at 10Gbit in the future. The onboard 1Gbps ethernet is connected to our LAN The Xavier is running ubuntu 18.04 for arm. This is the development platform that nVidia provides. uhd 4.0.0, gnuradio 3.8 and RfNoC 4 have been installed on the Xavier. The Xavier is given a simple flow to run under gnuradio-companion which consists of a USRP Source connected directly to the QT GUI Frequency sink (or Null Sink) The network buffers and mtu on the xavier are increased to at least those recommended. The result we get is a whole lot of ‘D’s output if we increase the sample rate beyond 2MSPS. The same result is found if we run the flow from the command line (without the gui). For comparison we have done a similar setup with a USRP E312 – connected to a xavier, a ubuntu 20 virtual machine and directly to a computer running ubuntu 20.04. In each case when we increase the sample rate beyond 2MSPS we get ‘O’s output. Can anyone please indicate what setup is required to achieve the 25MSPS that should be possible across this link? Thanks in advance _______________________________________________ USRP-users mailing list -- [email protected]<mailto:[email protected]> To unsubscribe send an email to [email protected]<mailto:[email protected]> You might want to run "benchmark_rate" from the UHD examples code to eliminate GR entirely at first--just to get a feel for what your machine is capable of. I'll note that the "network mode" in E312 (where it streams to a regular PC) has *considerable* performance constraints, and achieving even 2Msps is a bit of a miracle. The X310, on the other hand, is Niagara Falls. Any streaming-performance issues are your host. The FPGA on the X310 can stream to the xGIGe interfaces as fast as physics allows, pretty much. For a "order of magnitude" benchmark, I can achieve 10Msps from a B2xx into an Odroid XU4Q with 8-bit samples (there's a USB bandwidth issue there). I can even "do stuff" at 10Msps, including several different radio astronomy signal processing chains. I would expect your Xavier to be similar.
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