This assignment consists in creating a scheduler using Rate Monotonic policy that schedules three periodic tasks and one aperiodic task in background. These tasks have to write in the kernel log using a custom kernel module that allows to write on the kernel log using the write() function. Furthermore, it's possible to prevent the preemption between tasks by uncommenting some lines (read comments in the scheduler.c code) to use a mutex semaphore with priority ceiling access protocol.

First of all, you need to have root privileges so open a terminal window and type:

$ sudo su

Then from inside the rtos_assignment folder, you need to compile the kernel module using the Makefile, so simply type:

$ make

To install the module, type:

$ insmod my_module.ko

and to check if it was correctly installed, type:

$ /sbin/lsmod

and in the list you should find a module called my_module.

Read the major number associated to the driver (number next to my) by typing:

$ cat /proc/devices

and create the special file by typing:

$ mknod /dev/my c <majornumber> 0

Finally, compile the scheduler by typing:

$ g++ -lpthread scheduler.c -o scheduler

and run it with:

$ ./scheduler

To read the kernel log, use the command:

$ dmesg