Hi Daniele, all of what you describe is intended behavior.
First off, UHD tells you *exactly* what to do. Run: `sudo sysctl -w net.core.wmem_max=24862979` Nothing else. Just copy the previous line without the ``. The same goes for the rmem part. These changes are valid as long as your machine runs. It is not a permanent change. Thus, you need to rerun this command after every reboot. This is also intended. Reasonable defaults are set for your everyday use. UHD does stress the network quite a lot with a lot of IQ samples, thus, you see a warning that tells you what to do to improve performance. Other applications might work worse then. But as long as you want to use a USRP and UHD, this is fine. The whole `/proc` folder structure exists for the purpose that your Linux kernel communicates information to you. Lots of tools make use of that [0]. This is nothing UHD related but Linux in general. Certainly worthwhile to learn about it. Starting from there, you can figure out what the actual command does and how you would proceed if you would want to make this change permanent. Cheers Johannes [0] https://en.wikipedia.org/wiki/Procfs Am 09.05.19 um 16:40 schrieb Disco Daniele via USRP-users: > The number that seems configured every time I run uhd_usrp_probe is > > 1048576 that is the value present in the file wmem_max in the directory > > /proc/sys/net/core/ > > I searched also the way to modify this value and I found: > > sudo -s -H > > echo 24862979 > /proc/sys/net/core/wmem_max > > If now I test the number present in the file: > > cat /proc/sys/net/core/wmem_max > > the result is 24862979 > > and the command uhd_usrp_probe does not report warning. > > But if I restart the linux box, > > cat /proc/sys/net/core/wmem_max > > produce 1048576 again > > *From:*USRP-users [mailto:usrp-users-boun...@lists.ettus.com] *On Behalf > Of *Rob Kossler via USRP-users > *Sent:* giovedì 9 maggio 2019 16:28 > *To:* Marcus D. Leech <patchvonbr...@gmail.com> > *Cc:* usrp-users <usrp-users@lists.ettus.com> > *Subject:* [EXT] Re: [USRP-users] Configuration in sysctl.conf > > Have you done the same for "rmem_max"? Perhaps the continued warning > messages are related to this rather than wmem_max? > > Rob > > On Thu, May 9, 2019 at 10:01 AM Marcus D. Leech via USRP-users > <usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>> wrote: > > On 05/09/2019 08:25 AM, Disco Daniele via USRP-users wrote: > > Hi! > > I’m using a X310 on a linux box UBUNTU 18.04 > > Executing the command “uhd_usrp_probe” > > I obtain a lot of [WARNING][UDP] related to the dimension of the > send buffer > > Then there is the sentence: > > Please run: sudo sysctl -w net.core.wmem_max=24862979 > > So I’ve written in the file /etc/sysctl.conf, at the end > > net.core.wmem_max=24862979 > > I restarted the host but rerunning uhd_usrp_probe I reobtain the > same warning. > > Could you help me? > > PS: Now I’m using a 10GB Ethernet board plugged in the > workstation, using a couple of fiber optics between the X310 and > the work station > > Thank you > > Perhaps you have a syntax error in your sysctl file? > > > > _____________________________________________ > > logo1 > > Direzione e Coordinamento Vivendi SA > > * > **Daniele Disco* > *CT.TA.EI* > > > Via Reiss Romoli, 274 – 10148 Torino > tel . +39 011 228 7271 > cell. +39 331 600 1113 > > Fax. +39 06 4186 5196 > Tim Official: *Facebook* > <https://www.facebook.com/TimOfficialPage> - *Twitter* > <https://twitter.com/tim_official> > *www.tim.it* <http://www.tim.it/> > > Questo messaggio e i suoi allegati sono indirizzati > esclusivamente alle persone indicate. 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