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From: | Yeo Jin Kuang Alvin (IA) |
Subject: | Re: [Discuss-gnuradio] Underflow and Overflow |
Date: | Fri, 25 May 2018 02:19:29 +0000 |
Hi Neel, Sorry to ask, but is there a command I can input for Ubuntu to change the UHD version? Thank you in advanced! From: Neel Pandeya [mailto:address@hidden
Hello Alvin: I did not realize that you're using UHD 3.9.2. I would absolutely suggest that you upgrade to UHD 3.10.3.0. --Neel Pandeya On 24 May 2018 at 18:36, Yeo Jin Kuang Alvin (IA) <address@hidden> wrote: Hi Neel, I installed GNU Radio from the guide by ettus, and it automatically installed UHD_003.009.002-0-unknown
for me. Can I changed it to UHD 3.10.3.0 somehow without reinstalling? Thank you in advanced! From: Neel
Pandeya [mailto:address@hidden]
Hello Alvin: The Intel USB controllers generally work quite well. I'm not sure which version of UHD you're using, but I would suggest that you use UHD 3.10.3.0. If you fully performance-tune your system, given the system specifications, I don't see why you should not be able to get that flowgraph
in your initial email running without any overruns or underruns. --Neel Pandeya On 24 May 2018 at 18:06, Yeo Jin Kuang Alvin (IA) <address@hidden> wrote: Hi, Alright thanks. Do you have an Intel USB controller? (run "lspci") I do have it. Intel Corporation 8 Series/C220 Series Chipset Family USB xHCI (rev 04) Thank you in advanced! From: Neel
Pandeya [mailto:address@hidden]
Hello Alvin: It looks like your CPU has a maximum clock rate of 3400 MHz, but it's only ebing set to 2400 MHz. You need to set/force all cores
to run at their maximum clock rate. You really should be using a NVMe SSD disk, especially at your desired sampling rate of 20 Msps. Be sure that you disk is an NVMe
SSD, and if not, replace it with a new Intel or Samsung NVMe disk. Do you have an Intel USB controller? (run "lspci") --Neel Pandeya On 23 May 2018 at 19:02, Yeo Jin Kuang Alvin (IA) <address@hidden> wrote: Hi, Thank you for the guides and patience! Does the flowgraph run without overruns or underruns at 5 or 10 Msps? There are still overruns and underruns at 5 and 10 Msps. Does your system have an NVMe solid-state disk? I am not sure about this, but I doubt so. have you done any performance tuning? I followed the instructions and done sudo sysctl -w net.core.rmem_max=16777216 May I know why is the value at 16777216, seems like I have more UUU’s when I set to this value. Have you set the CPU governors to "performance" mode? Note that this must be done on a core-by-core basis. You also need to explicitly set the CPU clock speed to its maximum value. I’ve went into the link you sent and done followed the configurations and looks like the CPU clock speed is already max
seen below by running sudo dmidecode –t processor And this
Thank you in advanced! From: Neel
Pandeya [mailto:address@hidden]
Hello Alvin: Agree with what Nick said. Does the flowgraph run without overruns or underruns at 5 or 10 Msps? Does your system have an NVMe solid-state disk? Also, have you done any performance tuning? Have you set the read and write socket buffer sizes? sudo sysctl -w net.core.rmem_max=16777216 Have you set the CPU governors to "performance" mode? Note that this must be done on a core-by-core basis. You also need to explicitly set the CPU clock speed to its maximum value. --Neel Pandeya On 23 May 2018 at 00:12, Nick Foster <address@hidden> wrote: For starters, you almost certainly cannot write to your hard drive at 15Msps. You might not even be able to reliably read that fast without underruns. Reduce the sample rate until things start working. Disable or simplify parts of your flowgraph to see what's causing your problems. Isolate each problem and understand it before
moving on. Start simple and validate each part instead of building something complex to start with. Nick On Wed, May 23, 2018, 8:02 AM Yeo Jin Kuang Alvin (IA) <address@hidden> wrote:
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