Process and threads | Computer Science homework help

For this first assignment, you won’t be writing code; instead, you will be reading and executing the given below codes. Read the README instruction below for directions on how to compile and link the programs. Submit your answer in writing onto Blackboard.

  • Experiment 1. Thread and Process Creation
    Study the programs thr_create.c and fork.c. These programs measure the average time to create a thread using thr_create() and to create a process using fork(). Compile and execute the programs. What do you conclude from this experiment? Describe the reasons for the difference in timings.
  • Experiment 2. Processes vs Threads
    Study the two programs thr_shared.c and proc_shared.c. These programs are identical except that one uses threads and the other uses processes. Compile and execute the programs. What do you conclude from this second experiment? Explain the reason for the difference in behavior.
  • Experiment 3: The Update Problem
    Study the programs shared_data.c and SharedData.java. In these examples, multiple threads are both updating (i.e., modifying) a shared variable. Compile and execute both. Are the programs behaving “correctly”? What do you conclude from this experiment?
    README Instructions
  • Run the program on Linux platform.
  • To compile and run a C program (e.g., thr_create.c):
    gcc -o thr_create thr_create.c -lpthread thr_create
  • To build and run a classfile from the java code: javac SharedData.java
    java SharedData

page1image63834912page1image63835200page1image63835488page1image63835776page1image63836128page1image63836416

Submission Guidelines and Requirements

  • Submit your answers for all the experiments as a PDF file onto Blackboard
  • Include your name, UCM ID and Certification statement in your solution:
    //Your name
    // Your UCM ID
    //Certificate of Authenticity: “I certify that the codes/answers of this assignment are entirely my own work.”

thr_create.c

page2image105196192

#include <sys/time.h> #include <stdio.h> #include <pthread.h> #include <errno.h> main()

{
struct timeval start,end; long forktime;
double avgtime; pthread_t last_thread; int i;
int iters = 250;
void *null_proc();

gettimeofday(&start,NULL);

for (i = 0; i < iters – 1; i++) /* create (iters-1) threads */ pthread_create(&last_thread,NULL,null_proc,NULL);

pthread_create(&last_thread,NULL,null_proc,NULL); /* create last thread */ gettimeofday(&end,NULL);

pthread_join(last_thread, NULL); /* wait for last thread */ forktime = (end.tv_sec – start.tv_sec)*1000000 +

(end.tv_usec – start.tv_usec); avgtime = (double)forktime/(double)iters;

printf(“Avg thr_create time = %f microsecn”, avgtime); }

void *null_proc() {}

for (i = 0; i < iters; i++) /* create iters processes */ {

if ((pid = fork()) == 0) /* child process */ {

null_proc();

exit(1); }

else if (pid == -1) {

/* error */

printf(“error %dn”,errno);

exit(-1); }

else /* parent process */ continue;

}

/* only parent process reaches this point */ gettimeofday(&end,NULL);
for ( i = 0; i < iters; i++) /* have to do a wait for each child */ wait(&status);
forktime = (end.tv_sec – start.tv_sec)*1000000 +

(end.tv_usec – start.tv_usec); avgtime = (double)forktime/(double)iters;

printf(“Avg fork time =%f microsecn”, avgtime);

} null_proc() {
}

fork.c

page3image65305088

#include <sys/time.h> #include <stdio.h> #include <errno.h>

main() {

int pid;
struct timeval start,end;
int i;
long forktime;
double avgtime;
int iters = 250;
int status; gettimeofday(&start,NULL);

#include <sys/time.h> #include <stdio.h> #include <pthread.h> #include <unistd.h> #include <stdlib.h>

void *proc();
int shared_number;

main() {

int i;
pthread_t new_thread; int sleep_time;
int seed;

shared_number = 1;

printf(“Enter a positive integer for seed: “);
scanf(“%d”,&seed);
srand48(seed); /* initialize seed of random number stream */

/* thr_create(NULL,0,proc,NULL,0,&new_thread);*/ pthread_create(&new_thread,NULL,proc,NULL);
/* create new thread */

for (i = 0; i < 50; i++) {

printf(“MAIN THREAD: i = %d, shared_number = %dn”,i,shared_number); sleep_time = 100000.0*drand48(); /* generate random sleep time */ printf(“sleep time = %d microsecondsn”,sleep_time);
usleep(sleep_time);

shared_number = shared_number + 2; }

pthread_join(new_thread,NULL);

printf(“MAIN THREAD: DONEn”); }

thr_shared.c

page4image105085200

void *proc() {

int i = 0; int DONE;

DONE = 0; while (!DONE)

{ i++;

if (i%10000 == 0)
printf(“CHILD THREAD: i = %d,shared_number = %dn”,i,shared_number);

if (i > 5000000) DONE = 1;

}
printf(“CHILD THREAD: DONEn”);

}

#include <sys/time.h> #include <stdio.h> #include <pthread.h> #include <unistd.h> #include <stdlib.h> #include <errno.h>

void *proc();
int shared_number;

main() {

int i;
pthread_t new_thread; int sleep_time;
int pid;
int status;
int seed;

shared_number = 1;

proc_shared.c

page5image105361792

printf(“Enter a positive integer for seed: “); scanf(“%d”,&seed);

srand48(seed);

if ((pid = fork()) == 0) {

proc();

exit(0); }

else if (pid == -1) {

printf(“error %dn”,errno);

exit(-1); }

else
{ /* parent process */

for (i = 0; i < 50; i++) {

/* initialize random number stream */ /* child process */

/* error */

printf(“MAIN PROCESS: i = %d, shared_number = %dn”,i,shared_number); sleep_time = 100000.0*drand48(); /* generate random sleep time */ printf(“sleep time = %d microsecondsn”,sleep_time);
usleep(sleep_time);

shared_number = shared_number + 2; }

wait(&status); /* wait for child process */

printf(“MAIN PROCESS: DONEn”); }

}

void *proc() {

int i;
int DONE;

DONE = 0;
i = 0;
while (!DONE)

{ i++;

if (i%10000 == 0)

printf(“CHILD PROCESS: i = %d,shared_number = %dn”,i,shared_number); if (i > 5000000)

DONE = 1; }

printf(“CHILD PROCESS: DONEn”); }

shared_data.c

page7image64682480

#include <sys/time.h> #include <stdio.h> #include <pthread.h> #include <unistd.h> #include <stdlib.h>

void *proc();
int shared_number;

main() {

int i;
pthread_t new_thread; int sleep_time;
int number;
int seed;

shared_number = 1;
printf(“Enter a positive integer for seed: “); scanf(“%d”,&seed);
srand48(seed);

pthread_create(&new_thread,NULL,proc,NULL);

for (i = 0; i < 20; i++) {

number = shared_number;
printf(“MAIN THREAD: i = %d, shared_number = %dn”,i,shared_number); sleep_time = 100000.0*drand48(); /* generate random sleep time */ printf(“sleep time = %d microsecondsn”,sleep_time);

usleep(sleep_time);

shared_number = number + 2; }

pthread_join(new_thread,NULL);

printf(“MAIN THREAD: DONEn”); }

void *proc() {

int number,i; int sleep_time;

printf(“CHILDn”); for (i = 0; i < 10; i++)

{
number = shared_number;
printf(“CHILD THREAD: i = %d, shared_number = %dn”,i,shared_number); sleep_time = 100000.0*drand48(); /* generate random sleep time */ printf(“sleep time = %d microsecondsn”,sleep_time);
usleep(sleep_time);
shared_number = number + 200000;

}
printf(“CHILD THREAD: DONEn”);

}

SharedData.java

import java.util.Random;
public class SharedData extends Thread {

static Random gRandom = new Random(); static int gSharedNumber = 0;
private int gID;
public SharedData(int id) {

page8image105399776

this.gID = id; }

public void run() { for(int i=0;i<20;i++) {

int number = gSharedNumber; System.out.println(“SharedData[“+gID+”](i=”+i+”) = “+gSharedNumber); try { Thread.sleep(gRandom.nextInt(1000));
} catch (InterruptedException e) { /* ignore */ }
if(gID == 0) gSharedNumber = number + 1;
else gSharedNumber = number + 1000;

} }

public static void main(String args[]) throws Exception { SharedData sd1 = new SharedData(0);
SharedData sd2 = new SharedData(1);

sd1.start(); sd2.start();

sd1.join(); sd2.join(); }

}

Order a unique copy of this paper
(550 words)

Approximate price: $22

Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees


We value our customers, and so ensure that our papers are 100 percent original. Our Team of professionals does not miss the mark; they ensure that step by step each paper is written uniquely. We never duplicate or work as we compare papers rest assured. We deliver our work a day before time to ensure that you don’t miss your deadlines. It is not only doing the work but delivering it at the right time. We capture the consequences of late remittances. .

Money-back guarantee

We value customer satisfaction here at popularessaywriters.com and make sure that you get the best value for your Money. It happens that sometimes you can pay twice for your order or may want to cancel it, or you feel that it doesn’t meet your requirements; our money back guarantee will give you the opportunity to get back your money. We will also refund 100% of money paid double. In case your paper does not satisfy your requirements , we request that you notify us via writing within 2 days otherwise on the third day we will assume that you have been satisfied. Do all your correspondences through our email address popularessaywriters@gmail.com.

Read more

Zero-plagiarism guarantee

At popularessaywriters.com, our professional writers know the consequence plagiarism does for our clients. We have updated software’s such as article checker and copyscape to check for originality of the custom papers before submission of the final paper to the you. Our guarantee to the customer is that we will write 100% original papers for them that are quality, timely and of low cost. We have experienced professional and competent PhD writers who will write quality custom papers for you..

Read more

Free-revision policy

. At popularessaywriters.com, we are proud to provide top-quality Essay writing service to our esteemed customers. We are ready to take up that challenging academic assignment that is giving you sleepless nights and simplify it for you according to your desired requirements. We are willing to revise your paper if it does not meet your requirements. At popularessaywriters.com, we do not compromise with quality; thus, we offer unlimited free revisions until the customer is satisfied with their custom paper. Our unlimited free revision services are provided under the following terms:.. .

Read more

Privacy policy

Popularessawriters.com knows that client’s information is an essential tool for our company. It means that whatever the client requests from our service is kept strictly confidential. It means that whoever writes for this company understands the terms and conditions hence you should not be worried because you will never see your work somewhere else...

Read more

Fair-cooperation guarantee

Rest assured that we will always be attentive to your needs and requirements. We belief in the phrase treat your neighbour as you would want them to treat you. We leave nothing to chance and always look forward to a good interaction with each other.. .

Read more

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency