Prevention of a data race in a parallelised program, Operating System

Assignment Help:

Present your own fully documented and tested programming example illustrating the prevention of a data race in a parallelised program.

This is an example where total number of prime number between 2 and 10000 is being calculated. The order of memory accesses is prevented from being non-deterministic and from the code data race is avoided by making it parallelized with OpenMP directives.  The inconsistency can be seen by running the program consecutively for 3 or more times.

 

#include

#include

#include

#define MyThreads 4

#define num 10000

 

   int primeNum[num];

   int primeF[num];

 

   int is_prime(int v)

   {

    int i;

    int lim = floor(sqrt(v)) + 1;

 

    for (i = 2; i < lim; i++) {

           /* no need to check against known composites */

           if (!primeF[i])

               continue;

           if (v % i == 0) {

               primeF[v] = 0;

               return 0;

           }

       }

       return (v > 1);

   }

 

   int main(int argn, char **argv)

   {

       int i;

       int total = 0;

            printf("Enter a number greater than 2");

            scanf("%d", &num)

   #ifdef _OPEnumMP

       omp_set_dynamic(0);

       omp_set_num_threads(MyThreads);

   #endif

 

       for (i = 0; i < num; i++) {

           primeF[i] = 1;

       }

 

       #pragma omp parallel for

       for (i = 2; i < num; i++) {

           if ( is_prime(i) ) {

               primeNum[total] = i;

               total++;

           }

       }

        printf("total prime numbers that lie between 2 and %d: %d\n",

              num, total);

       return 0;

   }


Related Discussions:- Prevention of a data race in a parallelised program

Explain combined ult/klt approaches, COMBINED ULT/KLT APPROACHES Idea i...

COMBINED ULT/KLT APPROACHES Idea is to merge the best of both approaches Solaris is an illustration of an OS that combines both ULT and KLT  Thread creation complete i

Basic server model, Suppose we want to program a Web server; we could easil...

Suppose we want to program a Web server; we could easily do so without using concurrency, as follows: while(true) wait connection read from socket and parse url look up url cont

Explain wait for graph, Explain Wait for Graph a. Use a resource alloca...

Explain Wait for Graph a. Use a resource allocation graph to derive a wait-for graph.  b. Wait-for graph acquired by making an edge from p 1 to p 2 iff p 1 is waiting for

What are two probable uses of these multiple modes, Q. Several CPUs provide...

Q. Several CPUs provide for more than two modes of operation. What are two probable uses of these multiple modes? Answer: Although most systems merely distinguish between use

What are the necessary conditions for deadlocks?, What are the necessary co...

What are the necessary conditions for deadlocks? 1. Mutual exclusion :  Only one process at a time is able to use the resource. 2. Hold and wait :  A process should be holdi

What is a two state process model?, What is a two state process model? ...

What is a two state process model?   At any time a process is being implementing by a processor or not. Therefore a process may be in Running or not running state. When an Ope

Beladys anomaly algorithm, Q.  You have devised a fresh page-replacement a...

Q.  You have devised a fresh page-replacement algorithm that you think may be optimal. In a few contorted test cases Belady's anomaly occurs. Is the fresh algorithm optimal? Descr

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd