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RT-Preempt
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The RT-Preempt project does regularly provide patches which make the linux kernel capable of fulfilling hard realtime requirements. The aim is to eliminate all preemptivity and reactivity problems in the kernel over the time. The -rt patches are constantly being worked on for mainline by the community.
At Pengutronix, rt-preempt kernels are used in many industrial realtime projects. Using additional patches is a common use case in "deeply embedded" projects, for example being managed with build systems like ptxdist.
On "big" x86 systems, standard distributions are used as well as special embedded distros. In order to make the usage of rt-preempt easier in such projects, Pengutronix provides binary -rt kernel packages for the Debian distribution on http://debian.pengutronix.de.
The kernel being made available in this repository contains only the original -rt patches, not the patches provided by the Debian project. Our aim is to provide unmodified -rt patches to the debian community, in order to make it easy to send bug reports directly to the -rt developers.
Preparations
Add Pengutronix APT repository:
sudo wget -O /etc/apt/sources.list.d/pengutronix.list http://debian.pengutronix.de/debian/pengutronix.list
Update package list:
# sudo apt-get -q update
Add Pengutronix key to the system key ring:
# sudo apt-get -q --allow-unauthenticated install pengutronix-archive-keyring
Update package list again:
# sudo apt-get -q update
Installing the Kernel
| Version | Use Case |
|---|---|
Latest |
The most recent version of the -rt kernel. This version should be installed if the aim is to follow the -rt development closely and to test the latest releases. # sudo apt-get install linux-image-2.6-rt-${ARCH}
|
OSADL Latest Stable |
The Open Source Automation Development Lab (OSADL) declares certain kernels as "latest stable" from time to time. If PREEMPT_RT Linux realtime is intended to be deployed under production conditions, it is recommended to use OSADL's "Latest Stable" kernel version. Use the following command line to install it # sudo apt-get install linux-image-2.6-rt-osadl-${ARCH}
|
Manual Version |
For the case that a special -rt kernel version is required, there is the possibility to select a package with a specific version. To get a list of all available -rt kernels, there is the following command: # apt-cache showpkg linux-image-2.6-rt | sed '1,/Reverse\ Provides:/d' Chose the required version and install it with # sudo apt-get install ${KERNEL_NAME}
|
The following architectures ($ARCH) are available: 486, 686, 686-bigmen, amd64
${ARCH} depends on the machine that should run the
kernel. For x86 it usually is "686" or "amd64". Debian's kernel use
the same types, so if a Debian kernel is booted, consult
# uname -r
to get the right type for you.
Some of the packages suggested above are meta packages that depend on the corresponding kernel image package.Boot Loader
After the installation of an -rt kernel, the kernel will be automatically added to the boot loader menu. According to the configuration of the system, the new -rt kernel will not necessarily be configured as the "Default Kernel". That means that, during the boot sequence, it may be necessary to manually select the kernel to be booted.
For more information about bootloaders on debian, please see the bootloader article in the debian wiki.
Mailing Lists
Pengutronix doesn't provide a separate mailing list for the Debian -rt kernels. Please use the linux-rt-users mailing list for all discussions and bug reports.