Project 4 Solution

Instructions



You are to work on this project alone. You are allowed to discuss ideas with your friends (e.g., \hey, what do you think the rtl array is? I think it is the reverse lookup table that maps a physical page to the owning process." is acceptable. However, \hey, can I take a look at your code?" IS NOT!).




You are required to demonstrate your outputs to the TA. Await demo instructions from the TAs. Failure to demo will result in a 0!










Introduction






In this project, you will be implementing a virtual memory system. You will be given a simulator that manages memory models, but has some critical parts missing. This project will help you understand C programs that span multiple source les. We will guide you through the implementation of each of the missing parts step-by-step. It is in your best interest to understand underlying concepts before you type up code! The implementation of the virtual memory system is straightforward. If you are struggling to write code, then you should step back and contemplate on the concepts. If you do not understand the concept behind each step, then you will have a di cult time implementing them in code.







Project Folder Structure






The cs220 proj4 folder contains 3 sub-folders, the Make le and this pdf document. The simulator source code is in sim src folder, you will not be writing any code in this folder, however, you will be examining the code in sim src to understand the overall control and data ow. Your changes are required in impl src folder. The source les have been annotated with \TASK"s. You are to complete the tasks. You are not required to add any new les. The input folder contains sample inputs to test your code.










Point Distribution



TASK 1 (10 points): Complete the macros (in macros.h).

TASK 2 (25 points): Implement TLB lookup (in tlb-lookup.c).




TASK 3 (15 points): Implement page table lookup (in page-lookup.c).




TASK 4 (15 points): Implement physical page allocation (in page-replacement.c).




TASK 5 (25 points): Implement the page fault handler (in page-fault.c).




TASK 6 (10 points): Implement code to calculate access time (in eval.c).







Compiling and Running






To recompile the simulator, we have provided you with a Make le in the top-level directory. You can type in the command make in the terminal to build the project. When the project is nished building, there will be an executable in the top level directory called vsim. To execute this le, you must provide it with an le. Input les are found in inputs folder, and it provides four sample inputs:




sample1 { A basic input le that yields no page faults due to eviction.




sample2 { A reference le that provides a bit of everything (tlb miss, page fault, etc.).




sample3 { A reference le that should cause a large number of TLB hits.




sample4 { A reference le that should produce a large number of page faults.









If you wanted to run the simulator with the sample1 le, you would do the following:
1
$ . / vsim i n p u t s / sample1















There are several other command line options for the simulator that you can play around with, such as changing the memory size, page size, and the tlb size. You can change these parameters to see how they a ect the memory access time. The default settings are memory size = 16 values, page size = 2 values, and tlb size = 4.






Submitting the project






You will be provided submission instructions (including github repo setup) in the next few days.