Configuring Linux systems to support real-time operating system development

Configuring Linux systems to support real-time operating system development

With the development of embedded systems, real-time operating systems (RTOS) have been widely used in various application fields. In order to support the development of RTOS, we need to configure the Linux system to meet the real-time and predictability requirements. This article will introduce how to configure a real-time operating system development environment in a Linux system and provide some code examples.

1. Kernel configuration

First, we need to configure the Linux kernel to enable real-time functionality. You can configure it through the following steps:

1. Download the Linux kernel source code.

   First, we need to download the source code of the Linux kernel. You can download the latest stable version of the kernel source code from the official Linux website (www.kernel.org).

2. Compile the kernel.

   Decompress the downloaded kernel source code and enter the decompressed directory. Run the following command to compile the kernel:

   make menuconfig

   This will launch the kernel configuration menu. In the menu, we need to configure the following options:

   • General setup -> Preemption model

     Select "Fully preemptible kernel (RT)". This enables the real-time nature of the kernel.

   • Processor type and features -> Preemption Model

     Select "Voluntary Kernel Preemption (Desktop)". This enables kernel preemptibility, improving real-time performance.

   • Processor type and features -> Timer frequency

     Set the timer frequency to 1000 HZ.

   • Processor type and features -> Timer tick handling

     Select "Standard clock tick". This enables standard clock interrupt handling.

   • Processor type and features -> Timer slack

     Set the timer slack to 1.

   • Power management options -> CPU Frequency scaling

     Disable the CPU frequency adjustment function to avoid the impact of frequency switching on real-time performance.

   • Power management options -> CPU idle -> CPU idle governor

     Select "Menu". This disables automatic management of CPU idle states.

   After completing the configuration, save and exit the menu. Then, run the following command to compile the kernel:

   make -j4

   This will use 4 threads for compilation. Depending on the performance of the system, you can adjust the number of threads yourself.

   After the compilation is completed, run the following command to install the new kernel:

   make modules_install
   make install

   After the installation is completed, restart the system and select the newly compiled kernel to start.

2. Real-time function library

After configuring the kernel, we also need to install some real-time function libraries to support the development of real-time operating systems.

1. Install a scheduler that has less impact on real-time performance

   The default scheduler (CFS) of the Linux kernel has a greater impact on real-time performance. You can consider installing some alternatives. Schedulers such as "Real-Time Preemption Patch" (PREEMPT-RT) and "Staircase Deadline Scheduler" (SDS).

   For specific steps to install these schedulers, please refer to their official documentation.

2. Install the real-time function library

   You can use the following command to install the real-time function library:

   sudo apt-get install libc6-dev-i386
   sudo apt-get install libncurses5-dev
   sudo apt-get install build-essential

3. Real-time operation System development example

After configuring the real-time function, we can start developing the real-time operating system. Below is a simple example showing how to use real-time functionality in a Linux system.

First, create a new C file, such as "realtime.c", and write the following code:

#include <stdio.h>
#include <pthread.h>
#include <sched.h>
#include <stdlib.h>

void *realtime_thread(void *arg) {
    struct sched_param param;
    param.sched_priority = 99;
    if (sched_setscheduler(0, SCHED_FIFO, &param) == -1) {
        perror("sched_setscheduler() failed");
        exit(EXIT_FAILURE);
    }

    // 实时线程的代码
    // ...

    return NULL;
}

int main() {
    pthread_t thread_id;
    pthread_create(&thread_id, NULL, realtime_thread, NULL);
    pthread_join(thread_id, NULL);

    return 0;
}

In the above code, we create a real-time thread through the pthread library , and set it to the highest priority (99). In the code of the real-time thread, you can write tasks that require real-time guarantee.

To compile this code, you can use the following command:

gcc -o realtime realtime.c -lpthread

Run the generated executable file to run real-time tasks in the Linux system.

Summary

Through the above steps, we can successfully configure the Linux system to support the development of real-time operating systems. After configuring the kernel and installing the real-time function library, you can write and run tasks with real-time requirements. This will provide greater flexibility and predictability in the development of embedded systems.

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