CMPSC311 - Block Cache

Posted 2022-06-03 goodjava

Assignment #4 - Block Cache
CMPSC311 - Introduction to Systems
Programming
Summer 2019 - Prof. McDaniel
Due date: August 5, 2019 (11:59pm)
Overview
In this assignment you will again extend the driver written in the previous assignments.
Everything about the block device remains as before, except as described in the
specification here. At the highest level, you will extend the code to support many and
larger files and frame caching. All of the extensions will be made to the functions
modified in the previous section as well as a new file block_cache.c.
Block Driver Extension
The code addition to the driver will be the ability to support multiple open files at a
given time, as well as a frame cache for your block device. More specifically, the driver
must be able to support BLOCK_MAX_TOTAL_FILES files, all of which may be open at the
same time. The files have no maximum size. And secondly, you will also add a frame
cache to your driver implementation. It will store dynamically allocated frames in
a write through LRU cache you will implement. The function declarations are
provided to you in block_cache.h and shown below. You will need to check the cache
every time you read a frame to see if is already there and used the cached entry rather
than going to the bus. On writes, you will need to insert it into the cache if it doesn‘t
exist or update it if it does exist. The cache should allow for a maximum number of

CMPSC311留学生作业代写、代做Block Cache课程作业、代做c/c++设计作业
entries (the cache size). When the number of entries is exceeded, you need to delete a
frame (and deallocate the frame) per the cache replacement policy. The performance of
your cache will be evaluated with nine different cache sizes: 5, 10, 25, 50, 100, 250,
500, 1000, and 1024 cache entries. You can specify a cache size by
invoking block_sim with the ‘-c‘ option along with the size: ./block_sim -v -c 10
<workload_file>. You will be graded based on the performance of your cache (with
each of the listed cache sizes) against the workload.
Given the policy, the target performance to achieve for each size is:
Cache size Target hit ratio (%)
5 52.19%
10 53.71%
25 58.34%
50 67.34%
100 88.02%
250 99.12%
500 99.12%
1000 99.12%
1024 99.12%
The functions you must complete are as follows:
int set_block_cache_size(uint32_t max_frames);
// Set the size of the cache (must be called before init)
int init_block_cache(void);
// Initialize the cache
int close_block_cache(void);
// Clear all of the contents of the cache, cleanup
int put_block_cache(BlockIndex blk, BlockFrameIndex frm, void *frame);
// Put an object into the object cache, evicting other items as necessary
void * get_block_cache(BlockIndex blk, BlockFrameIndex blk);
// Get an object from the cache (and return it)
You should refer to the lecture on caching for hints on how to implement the cache.
Note that you will have to insert calls to the above functions in the existing code,
including during initialization of the driver, shut down, and during reads and writes.
The set_block_cache_size function is called by the main program to set the maximum
number of frames (and thus you don‘t have to call this in your code).
Assignment Details
Below are the step by step details of how to implement, test, and submit your device
drivers as part of the class assignment. As always, the instructor and TAs are available
to answer questions and help you make progress. Note that this assignment is
deceptively complicated and will likely take even the best students a substantial
amount of time. Please plan to allocate your time accordingly.
1. From your virtual machine, download the starter source code provided for this
assignment here.
2. Unpack the starter files into a temporary directory with the command:
tar xvfz assign4-starter.tgz
3. Once unpacked, there will be some new files and some new versions of old files
which we need to migrate over to your working directory. Before moving further, we
advise to copy your assign3 directory over to a new directory for assign4. We will
copy the following starter files into the new assign4 directory:
Makefile
block_sim.c
block_cache.c
block.cache.h
block_controller.h
libblocklib.a
workload/ (replace the old workload directory with this new one)
Important: Copy only the files listed above into the new assign4 directory.
4. Your task is to implement the cache functionality as described above, adding any
necessary changes to functions in block_driver.c to use your cache.
5. Add comments to all of your files stating what the code is doing. Fill out the
comment function header for each function you are defining in the code. A sample
header you can copy for this purpose is provided for the main function in the code.
6. To test your program, you will run it with the sample workload file provided. To do
this, run the program from the command line with:
make clean && make
./block_sim –v -c <cache_size> workload/cmpsc311-sum19-assign4-
workload.txt
You must use the "-v" option before the workload filename when running the
simulation to get meaningful output. Once you have your program running correctly,
you should see the cache performance statistics along with following message at the
end of the output:
[INFO] BLOCK simulation completed successfully.
Complete the cache unit test function with code that initializes the cache, creates
10,000 cache operations of random frame gets and puts, then closes the cache and
completely frees all of the memory associated with the created entries. Note that
the [-u] option on the command line will run this and the other unit tests. The test
should check that the data retrieved from the cache is correct (the bytes sent in are the
same ones you get out).
To turn in:
1. Create a tarball file containing the assign4 directory, source code and build files as
completed above. Submit the tarball to canvas by the assignment deadline
(11:59pm of the day of the assignment). The tarball should be named LASTNAME-
PSUEMAILID-assign4.tgz, where LASTNAME is your last name in all capital letters
and PSUEMAILID is your PSU email address without the "@psu.edu". For example,
if the professor was submitting a homework, he would call the file MCDANIEL-pdm12-
assign4.tgz.
Note: Any file that is incorrectly named, has the incorrect directory structure, or has
misnamed files, will be assessed a one day late penalty.
2. Before submitting the tarball, test it using the following commands (in a temporary
directory -- NOT the directory you used to develop the code):
% tar xvzf LASTNAME-PSUEMAILID-assign4.tgz
% cd assign4
% make
... (TEST THE PROGRAM)
Note: Like all assignments in this class you are prohibited from copying any content
from the Internet or discussing, sharing ideas, code, configuration, text or anything else
or getting help from anyone in or outside of the class. Consulting online sources is
acceptable, but under no circumstances should anything be copied. Failure to abide by
this requirement will result dismissal from the class as described in our course
syllabus.

因为专业，所以值得信赖。如有需要，请加QQ：99515681 或邮箱：[e-mail]

微信：codehelp