The goal of a fair-share thread scheduler is to ensure that all users get an equal share of the machine's processing rime. This means that all of a user's processes will share that user's portion of the CPU time and not infringe on another user's time. For example, under a completely even sharing scheduler, suppose that there are two users logged into a system, each running one process. User I's process will get scheduled 50% of the time, and User 2's process will get scheduled the other 50% of the time. If User 2 starts another process, User l's process will continue to get scheduled 50% of the time, but each of User 2's processes will nm 25% of the time. Use man sched_setscheduler to learn about the kernel scheduling policies.
Modify the source code of the Linux kernel to implement the described fair scheduler and construct an example to demonstrate that the scheduling is indeed fair. Use the Linux kernel version that we have provided in the user's home directory in your VM ((home/user). In addition, add a new system call to the kernel that tells the scheduler that the process calling it is to receive twice as much time, within the user's allotted time slot For example, a user nms three processes, A, B, and C. If the system call is not invoked, each process will receive approximately 33.3% of the user's processing time. If process A invokes the call, it will receive 50% of the tine, with B and C each receiving 25%.
You will be doing all your development and experiments within the virtual machine images. You will be modifying several kernel files to implement the scheduler and the system call, and will be running your virtual machine with the new kernel image. To grade your homework, we will directly be testing your implementation by logging into your virtual machine. Keep in mind that your virtual machines must.
Obtain kernel some .de MR your modification. We will be compiling the kernel ourselves during the evaluation. On Sakai. you will submitting the following two deliverables.
1. A mall containing all modification to the kernel files that you changed for the homework.
Please note that we require you to submit only the modified files. If you do not touch a file please do not upload it on Sakai. We will verify that the kernel source codes in the virtual machines are identical to the ones that you submitted on Sakai. Please keep any directory structure intact inside you tarball to make it easier to see where in the kernel your modified files go.
2. A PDF report describing (1) a pseudo code description of the fair share thread scheduler, (2) a list (2) of modification that you made to kernel. and (3) a description of your experiments to test the fair-share thread scheduler. Once we read your report, we should have a clear understanding of how you went about solving the problem.