Re: Realtime Kernel, UHD 4.0, GNURadio

[Johannes Demel]

Hi Anton,

This guide may help you:
https://kb.ettus.com/USRP_Host_Performance_Tuning_Tips_and_Tricks
I usually use the CPU Governor, Thread Priority Scheduling, Adjust 
Network Buffers, and Adjust Ethernet MTU sections.

I can run flowgraphs at 30.72MSps without hiccups. Thus, I suggest you 
check your host capabilities and probably more important: Check that GR 
is compiled and installed with `CMAKE_BUILD_TYPE=Release`.

Besides, you may want to investigate which thread (and thus GR block) is 
the culprit. A first simple approach would be to use htop and find out 
which thread is close to 100% CPU load. If you change the htop Display 
Options to "Show custom thread names" it should be fairly simple to get 
a better understanding of your issue.

Cheers
Johannes


On 05.05.22 20:52, Dobler, Anton wrote:
> Dear community,
>
>
> I am running UHD 4.0 and GNURadio 3.10 on a Ubuntu 20.04 with a N310 as 
> a SDR.
>
>
> When I execute the benchmark_rate example with DPDK enabled, I do not 
> see any under- or overruns even with the sampling rate set to 125 MHz, 
> however using GNURadio - DPDK enabled here as well - I do not achieve 
> that high sampling rate. The limit seems to be around 30MHz though.
>
>
> Do you know, apart from using taskset and isolcpus any other possibility 
> to achieve higher sampling rates?
>
>
> Would it be an option to use the realtime kernel available for Ubuntu 
> 20.04 and is this kernel compatible with GNURadio?
>
>
> Any help also with regards to the usage of taskset and isolcpus would be 
> highly appreciated!
>
>
> Thank you in advance!
>
>
> BR,
>
>
> Anton