Hi ,
here is my code where i tried to separate the computation into a process and the I/O into another process. when i do compile there is no error, but when i run it; it goes spinning and spinning without stoping..
even i declared the lock variabe in a separate header file like this:
extern bool lock;
bool lock= false;
and included as #include"shared.h"
Can any one correct it , thank u
#include <sys/types.h> /* pid_t */
#include <sys/wait.h> /* waitpid */
#include <stdio.h> /* printf, perror */
#include <stdlib.h> /* exit */
#include <unistd.h> /* _exit, fork */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <errno.h>
#include <sys/time.h>
#include <stdbool.h>
#define DATASIZE (10<<20)
bool lock= false;
bool TestAndSet(bool *target)
{
bool rv = *target;
*target = true;
return rv;
}
int main()
{
int counter= 0;
double A[200][200];
double B[200][200];
double C[200][200];
int i, j, k, m;
int outfile, result, count;
unsigned seed;
struct timeval before, after;
char *buff;
buff = (char *)malloc(sizeof(char)*(10<<20));
srandom(seed);
/* ==================================================================*/
for (i=0; i<200; i++)
for (j=0; j<200; j++) {
A[i][j] = random()/100.0;
B[i][j] = random()/100.0;
}
/* ==================================================================*/
gettimeofday(&before, NULL);
pid_t pid;
pid = fork();
if (pid ==-1) {
/*
* When fork() returns -1, an error happened.
*/
perror("fork failed");
exit(EXIT_FAILURE);
}
/* ================================================================*/
else
if(pid >=0)
{
/* =================================================================*/
if (pid == 0) {
/*
* When fork() returns 0, we are in the child process.
*/
gettimeofday(&before, NULL);
for (m=0 ; m < 10; m++) {
while(TestAndSet(&lock))
printf("spinning");
/* Computation */ /* STARTING COMPUTATION CRITICAL SECTION */
printf("Comuptation process iteration was allowed to start \n");
for (i=0; i<200; i++)
for (j=0; j<200; j++) {
C[i][j] = 0;
for (k=0; k<200; k++)
C[i][j] += A[i][k]*B[k][j];
}
counter++;
printf("Comuptation process iteration is finished \n");
/* ENDING COMPUTATION CRITICAL SECTION */
} /*===computation iterations=======for*/
lock = false;
} /* ================if pid == 0 ==================*/
else {
/*
* When fork() returns a positive number, we are in the parent process
* and the return value is the PID of the newly created child process.
*/
for (m=0 ; m < 10; m++)
{
while(TestAndSet(&lock))
printf("spinning");
/*======================critical section =========================*/
/* I/O */ /* STARTING I/O CRITICAL SECTION */
printf("I/O process iteration was allowed to start \n");
outfile = open("testfile", O_RDWR|O_CREAT|O_APPEND, 0777);
if (outfile <= 0)
perror("Error opening file\n");
else {
result = write(outfile, buff, DATASIZE);
if (result <= 0)
perror("Error writing file\n");
} /* if*/
close(outfile);
counter++;
printf("I/O process iteration is finished \n");
}
/* ENDING I/O CRITICAL SECTION */
int status;
(void)waitpid(0, &status, 0);
// wait(NULL);
// } /* for */
//} /*else*/
free(buff);
gettimeofday(&after, NULL);
count = (after.tv_sec - before.tv_sec) * 1e6;
count += (after.tv_usec - before.tv_usec);
printf("Total time in usec: %d\n", count);
printf("Counter final value: %d\n", counter);
} /* parent*/
} /* parent & child*/
return 0;
}
