From 1c2f92f7c72f23415fecb684ea82e800656873ce Mon Sep 17 00:00:00 2001 From: Johannes Mey <johannes.mey@tu-dresden.de> Date: Sun, 10 May 2020 13:16:38 +0000 Subject: [PATCH] Update README.md. this fixes #1 --- README.md | 44 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 6 deletions(-) diff --git a/README.md b/README.md index ea9746f..66b08c0 100644 --- a/README.md +++ b/README.md @@ -1,11 +1,43 @@ # Realtime Kernel for Ubuntu 18.4 -These are deb packages built for Ubuntu Bionic. +These are `deb` packages built for Ubuntu Bionic. -Used Kernel sources: -- kernel `linux-5.4.19-rt11_5.4.19-rt11.orig.tar.gz` -- realtime patch `linux-5.4.19-rt11_5.4.19-rt11-1.diff.gz` +## Information -Kernel config: -- Preemption Model: Fully Preemptible Kernel (RT) +The kernel is built automatically by the CI from the [linux kernel sources](https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/) version 5.4, using the latest kernel version for which a [real time patch](https://mirrors.edge.kernel.org/pub/linux/kernel/projects/rt/5.4/) is available. For more information on how the kernel is built, please review the `compile.bash` script. +It's `config` file is based on the config provided by a Unbuntu Bionic installation with two changes: +- The `preemption model` ist set to `Fully Preemptible Kernel (RT)`. +- `Compile the kernel with debug info (DEBUG_INFO)` is set to `no`. + +Before the build, if the new kernel version contains new config keys, the corresponding values are set to their defaults. + +## Installation + +- **⚠ ATTENTION** Make sure secureboot is disabled. Currently, the compiled kernel is unsigned and thus, will not work with secureboot. +- **⚠ ATTENTION** The repository does not contain the kernel packges, they are built by the CI and and can be downloaded. +- [Download the latest kernel packages built by the CI](https://git-st.inf.tu-dresden.de/ceti/realtime-kernel/-/jobs/artifacts/ci/browse?job=build-kernel). +- Install the packages using `dpkg -i`. + +## Verifying that the Realtime Kernel is Running + +- Reboot after kernel installation, selecting the new kernel in the boot loader. +- Run `uname -a`, the result should contain the kernel version number from the installed `deb` package as well as `PREEMPT RT`. + +## Set User Permissions + +- Add a group named realtime and add the user controlling your robot to this group: + ``` + sudo addgroup realtime + sudo usermod -a -G realtime $(whoami) + ``` +- Add the following limits to the realtime group in /etc/security/limits.conf: + ``` + @realtime soft rtprio 99 + @realtime soft priority 99 + @realtime soft memlock 102400 + @realtime hard rtprio 99 + @realtime hard priority 99 + @realtime hard memlock 102400 + ``` +- Log off and on again to let the group assignment and realtime priorities take effect (or, to be safe, restart). Use the command `groups` to check if the the current user belongs to the realtime group. \ No newline at end of file -- GitLab