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Questions tagged [preempt-rt]

PREEMPT_RT is the real-time patch for the Linux kernel

PREEMPT_RT is a real-time patch aiming at reducing the maximum latency experienced by tasks running on the Linux kernel. Some parts of the patch have been merged into the mainline kernel from time to time. The development is sponsored by the Linux Foundation under the Real Time Linux collaborative project.

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Disadvantage(s) of preempt_rt

the target hardware platform has limited horsepower, and/or you want the real-time job to put the smallest possible overhead on your system. This is where dual kernels are usually better than a native preemption system. From here:…
Aquarius_Girl
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What is the accuracy of interval timers in Linux?

I am trying to characterize timer jitter on Linux. My task was to run 100ms timers and see how the numbers work out. I'm working on a multicore machine. I used a standard user program with setitimer(), the same run as root, then with processor…
Paxton Sanders
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Yocto build for preempt_rt

I'm building a custom kernel for the beaglebone black. Following this guide (http://android.serverbox.ch/?p=1273) I'm able to boot to console successfully using a base image. When I try to build with the realtime kernel patch using command: bitbake…
BullBoyShoes
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Real-time benchmark between preempt_rt, Xenomai and RTAI

I need to compare performance between the preempt_rt patches, Xenomai and RTAI. They each have their own benchmarks but they don't give similar results and not all benchmarks are available in all three platforms. What I'm looking for is a benchmark…
odysseas
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Latency spikes while data-logging in real-time embedded Linux

I have a robot running control code with real time priority on a PREEMPT-RT patched Linux OS on a Beaglebone Black. All code is written in C and is running at 500Hz. I've noticed latency in the range of a few hundred milliseconds every so often when…
jekso
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How to improve real-time performance of 1ms timer in Linux?

I'm working on an embedded Linux project, using an arago distribution that is probably around version 3.3. I have configured a high-resolution Linux timer to wake-up my process once per millisecond. This works ok but there are two issues with the…
user1768576
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How to reduce the probability of page allocation failure?

Are there some methods that could be used by the Linux kernel to the probability of page allocation failure while both CONFIG-MIGRATION and CONFIG-COMPACTION are disabled? Are there some system settings that could make for this goal besides…
John
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Build an RT-application using PREEMPT_RT

I would like to write real-time Linux programs while using the real-time PREEMPT_RT. I found the official Wiki (https://rt.wiki.kernel.org/index.php/HOWTO:_Build_an_RT-application). There are some code examples but I would like to get the…
Txema R.
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How to communicate between processes in realtime Linux?

There are a lot of examples how to write realtime code for RT-Linux by FSMLabs but this distro has been abandoned many years ago. Currently PREEMPT_RT patch for vanilla kernel is actively developed but there are only few code examples on official…
Politechniczny
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Difference Linux Kernel 5.10 with / without PREEMPT-RT patch

With the current Version 5.10 of a vanilla linux kernel, one can configure the kernel as a low-latency version as the mainline have accepted multiple merge requests from the Preempt-rt patch team. However if one patch the vanilla kernel with it's…
sirius
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Function which takes a pthread as input and suspends it

I'm trying to port the real time Thread_Metric from ExpressLogic in POSIX, in order to benchmark PREEMPT_RT patches for Linux, Xenomai and RTAI for my thesis. They provide a C source file with the following functions, which you have to implement in…
ody
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Port handcraft systems to libcaf

I currently have an application which uses handcrafted actors. My plan is to to port it to libcaf. The current state is: I have one big global message queue where my systems (aka actors) subscribe to get their messages. They respond with messages…
schorsch_76
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Comparing different real-time Linux solutions (PREEMPT_RT, Xenomai, Ubuntu lowlatency, among others)

how could I compare different real-time Linux solutions (PREEMPT_RT, Xenomai, Ubuntu lowlatency, among others)?. I am using rt-tests (and cyclictest) for PREEMPT_RT. I read Lachesis testsuite as an option. What would be a testsuite valid?. Thank…
Txema R.
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CPP function's execution duration follows bimodal distribution

Why does my C++ function's execution times follow a bimodal distribution? In my C++ code, I load an external library, a data processor (either a cpp class compiled to a shared object which is dynamically loaded, or a python class), then call its…
Alqio
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How to build raspbian with custom kernel 5.10 (PREEMPT RT)

I am trying to enable PREEMPT RT (Fully preemptive model) in Linux kernel 5.10. However, I get a black screen when booting from the custom kernel image and I have no clue why that happens. Any help is greatly appreciated. Here are all my steps: All…
remus
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