Johannes Demel wrote: > Hi all, > > thanks for your suggestions. > > A few more details: > > * Ryzen 5900X CPU > * UHD reports USB 3. With USB2 it would probably fail above \~8MSps. > * Ubuntu 22.04 with GCC 11.2, Python3.10 > > I tried 2TX streams alone at 30.72MSps. works. check. > I tried 2RX streams alone at 30.72MSps. works. check. > > I tried configurations with > > * num_recv_frames=num_send_frames=256 > * num_recv_frames=num_send_frames=512 > Doesn't help. > > The error pattern looks like this: > UUUUUUUUO\[D00:00:07.60063828\] Detected Rx sequence error. > > I tried > > * send_frame_size=recv_frame_size=8000 > also in conjuntion with the num_xxx_frames configurations. But that > didn't help either. > > I will try to use UHD 4.1 on that machine. If that works, I'll just > switch back. Otherwise, I'd get suspicious of Ubuntu and the hardware. > > Cheers > Johannes > > On 07.09.22 17:17, McKnight, Ryan wrote: > > > I have found after much trial and error that adding the arguments > > “recv_frame_size=8000,num_recv_frames=512” to the device string allows > > for me to sample at the full 56 Msps rate on the B series devices > > without any overruns (tested using UHD 4.2.0.1 on both Debian 11 and > > Arch Linux on various computers). I haven’t tried transmitting at all > > though so not sure if there are better arguments for that. One > > additional thing to double check for is that your device is actually > > connecting using USB 3.0, I have found a surprising amount of bad USB3 > > cables that would only link up at USB2 speeds (check using “sudo lsusb > > \-tv” after running uhd_usrp_probe to load firmware onto the device, > > should show speed of 5000M). > > > > *From:* [email protected] [[email protected]](mailto:[email protected]) > > *Sent:* Wednesday, September 7, 2022 10:31 AM > > *To:* [email protected] > > *Subject:* \[External\] \[USRP-users\] Re: B210 reporting U/O on Ubuntu > > 22.04 > > > > *Use caution with links and attachments.* > > > > [email protected] <mailto:[email protected]> wrote: > > > > ``` > > [email protected] <mailto:[email protected]> wrote: > > > > Hi, > > > > I can only confirm that I see the same result: 24MHz is working, > > starting from about 24.5MHz there’s a lot of underruns. > > > > My CPU: AMD Ryzen Threadripper 2990WX, 128GB RAM, motherboard > > Asus X399. > > > > … and the system is Ubuntu 20.04 with UHD 4.2.0.1. > > ``` > > > > But with UHD 4.1.0.6 there situation is exactly the same (not working > > for >= 24.5M), so if you’ve got it somewhere working it would be worth > > sharing: > > > > * your exact UHD revision, > > * specs of your PC.
If you could capture situation where it worked and stopped working on the same machine that would get you much closer to solving the issue. You could write a test and use it for automatic git bisect (git bisect run): https://lwn.net/Articles/317154/ If it’s UHD fault this can show you first commit that worsened maximum transfer rate. Best Regards,\ Piotr Krysik
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