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Questions tagged [realtime]

Related to the use of Ubuntu as a real-time OS, whether through use of a patch, replacement kernel or other method. This is often desired in the context of industries such as automation and CNC machines, as well as certain audio applications. Questions may relate to specific real-time patches/kernels, integrating those patches/kernels on an Ubuntu system, or using an RT Ubuntu system in a given application.

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Installation Ubuntu server on top of an existing one

Actually I'm developing a web application using PHP and realtime Chat application and notications using NodeJs. In a Local network There is an ubuntu server to connect some windows machines to make a ...
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Error in patch: during installing RT Linux patch for Ubuntu

I tried to convert my Ubuntu to be real time Ubuntu. I followed the steps of RT Linux, but I got an error in the patch step. Results of patch -p1 < ../patch-5.4.129-rt61.patch : can't find file to ...
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Make error while installing real-time patch

I am trying to install the real-time kernel patch 5.10.41-rt42 on an x86 machine that is running Linux 20.04. I followed the steps listed in this link (https://docs.ros.org/en/foxy/Tutorials/Building-...
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Installing real time patch for Ubuntu 20.04

I am trying to install Real time patch on ubuntu 20.04 I followed many steps and for each trial it took about 4 hours to complete. Unfortunately none of these trials worked (in the links below). I ...
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3 votes
2 answers
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Capture script output to add datetime to ouput in realtime

I'm looking to capture the output of a shell script execution in real time to enrich it with information giving the date and time. To illustrate, I have for example a script of this type that I must ...
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What are the risks to update 18.04.5 kernel (5.4.0-74) to the latest 5.4.125 to match the PREEMP_RT patch?

Good day everyone! I see that uname -r returns 5.4.0-74 in my 18.04.5 I don't see any version like this at kernel.org. Why the dash? I hear that Ubuntu makes changes to their kernel. This suggests ...
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1 vote
1 answer
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Ubuntu 20.04 setting PREEMPT_RT - Loading initial ramdisk

I am trying to update the kernel of Ubuntu from 5.8.0-50-generic to 5.9.1-rt20 (because there was no patches for 5.8.*, not sure why), but the system freezes after Loading initial ramdisk. Same thing ...
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1 vote
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Ubuntu Studio 20.10 Loopback / Monitor Microphone Realtime

How could I further reduce delay? Audacity seems to add a bit more delay. So I have routed input to output, and enabled realtime, through QjackCtl. I still notice quite a bit of delay. I am at the ...
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1 vote
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Using RT kernel with Nvidia on Ubuntu Mate

I'm trying to use the linux-rt kernel in Ubuntu Mate. It installs and runs fine. The rub is, I need to retain Nvidia mode, as the laptop's hdmi output runs solely through the external card. With the ...
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1 vote
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RT Patch on Raspberry pi 4 running ubuntu 18.04 LTS

So I've been using ubuntu 18.04 LTS on a raspberry pi 4 with 4GB RAM. I've found multiple articles explaining how install a preempt rt patch on AMD based systems but have been unable to so on my raspi....
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1 vote
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Support RTOS in Ubuntu 18.04 OS

I have installed Ubuntu 18.04 OS in my system, for configuring the Petalinux in my PC so that I can build real time application. For that, I have some queries related to this. How to enable realtime ...
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2 votes
1 answer
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Bash SH - Set a new var name including in that name another var

I just need to create an incremental var name inside a loop. The variable must use "in the var name the number of the cycle". Example inside a loop: # on Cycle=1 MyVar$Cycle=Exec$Cycle # (equal to ...
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Unable to fix Real Time Permissions with Ubuntu Studio Control

What I expected to happen: Use the Ubuntu Studio Control app to set up real time (low latency) permissions What happened instead: When I click the button to fix real time permissions, it gives me a ...
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Do we have any ways to retrieve the list of process and threads which are in runnable state(not running state) in ubuntu?

My requirement is to do dynamic cpu shielding in C program based on the queue length of runnable threads(but not running threads which are waiting for CPU availablity) in Realtime operating systems-(...
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6 votes
1 answer
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How do I get the newest lowlatency-kernel on 18.04 LTS?

When installing the linux-lowlatency package on 18.04 LTS, the lowlatency-kernel version 4.15 is installed, while the -generic kernel has been updated to 4.18 since the LTS release. 4.18 linux-...
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2 votes
0 answers
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How can I efficiently record 3d games/3d programs in real-time?

As per subject would like to efficiently record 3d games/3d apps running full screen. I have an Nvidia 2080 Ti and I've heard about NVENC and obs-studio. Has anyone any suggestion? Can I just use it ...
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Installing old kernel 3.4.69 in Linux 18.04 LTS

Can I possibly install a kernel 3.4.69 in place of the kernel 4.15? I have tried to do it for 3.4.4 and have been unsuccessful. What can I do? I really need 3.4.69 for Etherlab 2.1.
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1 vote
1 answer
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Error in build while installing RTAI in Ubuntu 18.04

I am trying to install RTAI 5.0.1 on Ubuntu 18.04 LTS in Linux Kernel 4.1.18. I was following this tutorial. But unfortunately I am stuck in this part make -j `getconf _NPROCESSORS_ONLN` deb-pkg ...
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(initramfs) /cow format specified as aufs and no support found

I added a Real-Time patch to my existing Ubuntu 14.04 kernel to make it soft RT Linux. I've the steps for RT Linux here https://stackoverflow.com/questions/51669724/install-rt-linux-patch-for-ubuntu ...
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2 votes
0 answers
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Why is the canary starving? [duplicate]

I'm running Kubuntu 14.04 and my machine is nearly locked up. I apparently have a canary problem. Here is the log just before the bird started chirping: May 10 21:38:06 Morchella NetworkManager[1010]...
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1 answer
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Making Liquorix default kernel with native NVIDIA drivers for Ubuntu 16.04 for enhanced gaming and realtime functionality

I've been interested in running the Liquorix kernel for gaming and realtime performance enhancements. It's a pretty straight foward installation, but I found that it was incompatible with NVIDIA ...
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3 votes
1 answer
4k views

Low Latency Kernel Downsides? [duplicate]

I'm considering moving from stock Ubuntu to Ubuntu Studio. My only concern is the low latency kernel. I've looked into what exactly it is, and know it will be great for my audio work, but I am ...
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Problem with real-time clock since upgrading to Ubuntu 17.10

SEE UPDATES BELOW I recently upgraded from Ubuntu 17.04 to Ubuntu 17.10 using the software update process. The update completed without any errors, and Ubuntu 17.10 is now running without any major ...
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Realtime equalizer?

What realtime equalizers are there that work with JACK? I have heard of Calf Studio Gear, but not sure if it will work or how good it is. Ones that won't work are: pulseaudio-equalizer, jackeq, jamin....
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How to integrate Xenomai 3 with Nvidia cuda?

I use Ubuntu 16.04.2 64bits. I heard that Xenomai 2.x/3.x could not support Nvidia CUDA drivers. Is that true? If yes, how to solve it? Is there exist any software that can allocate one CPU ...
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23 votes
2 answers
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timedatectl- NTP Sync cannot set to yes [duplicate]

I tried so much different things of installing ntpq or other stuff but nothing works. I dont can change it to yes. I hope someone can help here. I had Ubuntu 16.04 This is my terminal output of the ...
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3 votes
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Does Ubuntu Core support real-time?

Does Ubuntu Core's kernel support (hard) real-time? If not, is it using a standard kernel, which can be patched with the CONFIG_PREEMPT_RT set?
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1 answer
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ulimit: Unknown option “-r”

I'm trying to get JACK running in RT mode and I need to determine whether I'm allowed the necessary real time priority. Around the internet I found that ulimit -r or more genreally ulimit -a can tell ...
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1 answer
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JACK cannot start in realtime mode despite membership in audio group

My jack server is unable to start in realtime mode despite me being in the audio group. This is my setup: zegkljan@eddie:~$ lsb_release -r Release: 16.10 zegkljan@eddie:~$ echo $USER zegkljan ...
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How to install realtime kernel on Ubuntu Live USB

I am using Ubuntu Live USB stick 16.04.1 with boot toram and persistence option. So far best sounding setup for audio streaming (Firefox+AdobeFlash+Tidal). It is also best setup in terms of usability ...
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Question about the RTAI and version Of kernel

I have a ubuntu 3.8.0-29 geniric and the gcc 4.6.3 . I will to install the RTAI , what is the version of kernel and the version of kernel to download ?
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How install Real Time Application Interface (RTAI) in ubuntu 14.04

I have Ubuntu 14.04 and I want to install rtai , my version kernel is : 3.16.0-30-generic. How to install the Real Time Application Interface Rtai of kernel 3.16.0-30-generic?
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Problems compiling a kernel (3.4.110) on xubuntu 15.10

I am not sure if i am in the right forum for this, because it's more of a debian/kernel thing, but it is worth a try. I have to set up a linux system to work with EtherCAT ( for a machine control ). ...
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Hard disk's too slow to play a huge raw AVI file

I have a huge AVI file. The video player (VLC) stops every about 10 seconds because the HDD doesn't read fast enough. (details here) I want to be able to play this video. Anyone knows a workaround? ...
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VLC can't play large raw avi 1080p video

I recorded a huge raw avi video using SimpleScreenRecorder but it can't be played smoothly. Every about 10 seconds the video stops to render. How can I avoid this. I don't think my computer can't ...
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5 votes
1 answer
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How to get to a perfect jackd configuration that works trouble-free and out of the box?

While working on a PPA to provide binaries for Sonic Pi, the users of the PPA binaries keep stumbling over jackd. How to make things easier for them? Sonic Pi is an educational music tool that ...
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1 answer
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How to get debuginfo package for -rt kernel

I have Ubuntu 14.04 with 3.14.3-rt4 kernel. I have to use SystemTaptool and I must have debug symbols to use it. I follow the instruction in here but there are no debug symbols for my kernel and when ...
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4 votes
1 answer
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What is clamd's function?

I understand that there is currently no real-time AV for Linux, or at least not using ClamAV. So what is clamd's function then? Because that talks about on-access scanning, so what is that if not real-...
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1 vote
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Control Alsa in real time with external controller?

Okay so after hunting down old threads and questions, I feel it's best to just ask this and see if I can get some help. My question is how in the world do I control Alsa externally with my Korg micro ...
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Mixed criticality system based on Ubuntu

Is there a way to implement a mixed criticality system based on Ubuntu? I.e. if we have some software module that is complex and non-critical and we want to develop it as usual on Ubuntu. And we have ...
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1 answer
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Conky - Command Output Display Limited to 256 Bytes 'tail -n20 logfile.txt'

I am trying to display the contents of a large log file on the desktop using conky. I would like the 'window' to occupy the upper half of the desktop, and show the 20 most recent lines. I use the ...
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2 votes
1 answer
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Start jackd with realtime priority with upstart

I'm trying to start jackd with realtime priority at boot with an uptstart script but with no success so far. I'm using ubuntu server 14.04. My upstart version is 1.12.1. The user and group I'm using ...
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2 votes
1 answer
804 views

How to disable Lazy Preempt in kernel

I'm relatively new to Linux and working on getting a real-time kernel up and running for robot applications. I'm on Ubuntu 14.04, using kernel 3.14.3 and the 3.14.3-rt5 real-time patch. Also using x86-...
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44 votes
6 answers
40k views

A2DP on PulseAudio - terrible choppy/skipping audio

I have paired my Bluetooth headset with my Ubuntu 12.04 laptop with a Bluetooth chip inside: lsusb | grep Bluetooth Bus 003 Device 003: ID 045e:0745 Microsoft Corp. Nano Transceiver v1.0 for ...
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1 vote
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"ERROR: Kernel configuration is invalid"

I have been stuck on this issue for two days now and couldnt find a fix for this. I installed a realtime kernel with sudo apt-get install linux-rt because KauNet (which is an ipfw extension) ...
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0 votes
1 answer
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VisualBoyAdvance Battery Has Run Dry

I recently downloaded VBA and Pokemon Emerald. The game says "The Internal Battery has run dry" I've been told to go to Options>Emulator>Real Time Clock, but there is no clock! I have checked ...
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Multiple kernels choices realtime or no realtime

I have a dell latitude d510 currently running xubuntu 13.04 and linux 3.8. I want this machine to host JACK processes together with EDIROL UA-25 during a live session and therefore, it needs an RT ...
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1 vote
2 answers
2k views

What is the purpose of the RTAI package in Ubuntu

RTAI (Realtime Application Interface) is a Linux kernel patch, that exposes an API to userland processes, which can be used to create very low latency and jitter programs for realtime tasks. I've ...
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Ubuntu can be used as Hard Real time OS? [duplicate]

I want OS for Beagleboard which can support HARD REAL TIME OS Feature. is Ubuntu HARD Real time OS ?
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2 votes
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How do I install a real-time kernel with a patch I need to apply? [closed]

I have ubuntu 12.04 with kernel 3.5. I have to install the RT_PREEMPT patch and I followed these steps: sudo apt-get install kernel-package fakeroot build-essential libncurses5-dev mkdir -p ~/tmp/...
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