2022 Fall Semester Operating Systems Lecture Homework
mytaskinfo is a kernel module that creates a file named mytaskinfo in /proc filesystem. It serves as a interface between internal kernel data structures and user.
mytaskinfo takes the number of processes and calculates the utime, stime information of the given number of processes with the largest value (utime+stime) in seconds and prints this information and the se.vruntime information calculated by the kernel and used in CFS.
utime : is the time the process has been in user mode. In other words, it represent the CPU usage time of the process itself
stime : is the time the process has been in kernel mode. It means that stime represents the time of operations performed by the system for the process.
vruntime : is the weighted time a task has run on the CPU
- type
make, generates kernel object - type
sudo insmod mytaskinfo.ko, inserts module to kernel - you can check if it is installed by
sudo lsmod | grep mytaskinfo
For instance, if you want to see 2 processes have the biggest total time
echo "2" > /proc/mytaskinfocat /proc/mytaskinfo
The only problem is that it prints until it reaches BUFSIZ limit. It should be print until end of the text.