[SOLVED] Csc369 – assignment 3 – page tables and replacement algorithms  p0

Introduction
In this assignment, you will have to simulate the operation of page tables and page replacement. As I keep saying: the way to gain a solid understanding of the theory is by applying the concepts in practice.
You have two tasks in this assignment, which will be based on a virtual memory simulator. The first task is to implement virtual-to-physical address translation and demand paging using a two-level page table. : The second task is to implement four different page replacement algorithms: FIFO, Clock, exact LRU, and OPT.
Before you start work, you should complete the set of readings about memory, Assignment Project
Exam Helpif you haven’t done so already: Paging: Introduction (http://pages.cs.wisc.edu/~remzi/OSTEP/vm-paging.pdf)

Requirements
Setup
You will find the starter code HERE (starter.tar.gz). It is your responsibility to add the code in your repository and make sure that you submit all the necessary files!
DO NOT MANUALLY CREATE A NEW DIRECTORY ‘A3’ IN YOUR REPOSITORY! An empty directory
called ‘A3’ should be created for you automatically when you log into MarkUs and go on your A3 link. Just do an svn update to see the newly-created ‘A3’ directory in your repository. As usual, please make sure in advance that you can access your A3 directory, to avoid last-minute surprises.
Compile the trace programs and generate the traces.
Task 1 – Address Translation and Paging

Implement virtual-to-physical address translation and demand paging using a two-level pagetable.
The main driver for the memory simulator, sim.c, reads memory reference traces in the format produced by the fastslim.py tool from valgrind memory traces. For each line in the trace, the program asks for the simulated physical address that corresponds to the given virtual address by calling find_physpage, and then reads from that location. If the access type is a write (“M” for modify or “S” for store), it will also write to the location. You should read sim.c so that you understand how it works but you should not have to modify it..
The simulator is executed as ./sim -f <tracefile> -m <memory size> -s <swapfile size> -a
<replacement algorithm> where memory size and swapfile size are the number of frames of simulated
physical memory and the number of pages that can be stored in the swapfile, respectively. : The swapfile size should be as large as the number of unique virtual pages in the trace, which you should be able to determine easily.
There are four main data structures that are used:
1. char *physmem: This is the space for our simulated physical memory. We define a simulated page size (and hence frame size) of SIMPAGESIZE and allocate SIMPAGESIZE * “memory size” bytes forEmail: physmem.
2. struct frame *coremapQQ: 749389476: The coremap array represents the state of (simulated) physical memory. Each element of the array represents a physical page frame. It records if the physical frame is
in use and, if so, a pointer to the page table entry for the virtual page that is using it.
3. pgdir_entry_t pgdir[PTRS_PER_PGDIR]: We are using a two-level page table design; the toplevel is referred to as the page directory, which is represented by this array. Each page directory entry (pde_t) holds a pointer to a second-level page table (which we refer to simply as page tables, for short). We use the low-order bit in this pointer to record whether the entry is valid or not. The page tables are arrays of page table entries (pte_t), which consist of a frame number if the page is in (simulated) physical memory and an offset into the swap file if the page has been written out to swap. The format of a page table entry is shown here:
Note that the frame number and status bits share a word, with the low-order PAGE_SHIFT bits (12 in our implementation) used for status (we only have 4 status bits, but you can add more if you find it useful). Thus, for a given physical frame number (e.g. 7), remember to shift it over to leave room for the status bits (e.g., 7 << PAGE_SHIFT) when storing into the pte and to shift it back when retrieving a frame number from a pte (e.g., p->frame >> PAGE_SHIFT).
To complete this task, you will have to write code in pagetable.c. Read the code and comments in this file — it should be clear where implementation work is needed and what it needs to do. 程序代写代做 CS 编程辅导 The rand replacement algorithm is already implemented for you, so you can test your translation and paging functionality independently of implementing the replacement algorithms.
Task 2
Using the starter code, implement each of the four different page replacement algorithms: FIFO, exact LRU, CLOCK (with one ref-bit), OPT.
You will find that you want to add fields to the struct frame for the different page replacement algorithms. You can add them in pagetable.h, but please label them clearly.
Once you’re done implementing the algorithms, run all three programs : from the provided traceprogs, plus a fourth program of your choosing with interesting memory reference behaviour, using each of your algorithms (include rand as well). For each algorithm, run the programs on memory sizes 50, 100, 150, and 200. Use the data from these runs to Assignment Project Exam Helpcreate a set of tables that include the following columns. (Please label your columns in the following order,)
Hit rate
Hit count
Miss count
Overall eviction count
Clean eviction count
Dirty eviction count
Write up
Include a file called README.txt or README.pdf that includes the following information.
The tables prepared in Task 2
One paragraph comparing the various algorithms in terms of the results you see in the tables.
A second paragraph explaining the data you obtained for LRU as the size of memory increases.
Marking Scheme
Task 1: 35% Task 2: FIFO 5%
LRU 10%
CLOCK 10%
OPT 15%
(must be able to run all traces in a reasonable amount of time)
Tables 5%
Comparison paragraph 5%
LRU description 5%
Program readability and organization 10%
Submission
Additionally, you must add and commit an INFO.txt file, which contains as the first 3 lines the following:
your name your UtorID
Aside from this, please feel free to describe problems you’ve encountered, what isn’t fully implemented (or doesn’t work fully), any special design decisions you’ve taken, etc. :
Make sure your code compiles without any errors or warnings.
Make sure you have included all the files needed to correctly run your programs. Make sure you have included the INFO.txt file and the correct revision in it. As previously, to check that your assignment submission is complete, please do the following:

1. create an empty temporary directory in your cdf account (not in a subdirectory of your repo)
2. check out a copy of your repository for this assignment
3. verify that your README and INFO.txt files are includedQQ: 749389476
4. run make and ensure that you are able to build sim without any errors or warnings (This is an excellent way to verify that all files have been committed to the repo.)
5. run a few tests using the same traces you used to create the tables in your README, to ensure that your code behaves as you expect
6. congratulate yourself and enjoy a well-earned break, knowing that your strategy and hard work will pay off!

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