feat: update structure

cs2106/labs/lab3/progs/part3/barrier.c

@@ -0,0 +1,55 @@
+#include <semaphore.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/shm.h>
+
+int nproc = 0;
+// count must be a semaphore
+int *count;
+sem_t *barrier;
+sem_t *countMut;
+int barrierShmId, countShmId, countMutShmId;
+
+void init_barrier(int numproc) {
+  nproc = numproc;
+  barrierShmId = shmget(IPC_PRIVATE, sizeof(sem_t), IPC_CREAT | 0600);
+  countMutShmId = shmget(IPC_PRIVATE, sizeof(sem_t), IPC_CREAT | 0600);
+
+  countShmId = shmget(IPC_PRIVATE, sizeof(int), IPC_CREAT | 0600);
+
+  barrier = (sem_t *)shmat(barrierShmId, NULL, 0);
+  countMut = (sem_t *)shmat(countMutShmId, NULL, 0);
+
+  count = (int *)shmat(countShmId, NULL, 0);
+  sem_init(barrier, 1, 0);
+  sem_init(countMut, 1, 1);
+}
+
+void reach_barrier() {
+  sem_wait(countMut);
+  *count += 1;
+  sem_post(countMut);
+  if (*count == nproc) {
+    sem_post(barrier);
+  } else {
+    sem_wait(barrier);
+    sem_post(barrier);
+  }
+}
+
+void destroy_barrier(int my_pid) {
+  if (my_pid != 0) {
+    sem_destroy(barrier);
+    sem_destroy(countMut);
+    shmdt(count);
+    shmdt(barrier);
+    shmdt(countMut);
+    shmctl(countShmId, IPC_RMID, 0);
+    shmctl(barrierShmId, IPC_RMID, 0);
+    shmctl(countMutShmId, IPC_RMID, 0);
+    // Destroy the semaphores and detach
+    // and free any shared memory. Notice
+    // that we explicity check that it is
+    // the parent doing it.
+  }
+}

cs2106/labs/lab3/progs/part3/barrier.h

@@ -0,0 +1,3 @@
+void init_barrier(int);
+void reach_barrier();
+void destroy_barrier(int);

cs2106/labs/lab3/progs/part3/bigsmall-par.c

@@ -0,0 +1,101 @@
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "barrier.h"
+#include "config.h"
+
+#define NUM_PROCESSES 8
+
+int main() {
+  int vect[VECT_SIZE];
+  int pid;
+  int largestShmId, smallestShmId;
+  int *largest, *smallest;
+  init_barrier(NUM_PROCESSES + 1);
+
+  largestShmId =
+      shmget(IPC_PRIVATE, sizeof(int) * NUM_PROCESSES, IPC_CREAT | 0600);
+  largest = (int *)shmat(largestShmId, NULL, 0);
+  smallestShmId =
+      shmget(IPC_PRIVATE, sizeof(int) * NUM_PROCESSES, IPC_CREAT | 0600);
+  smallest = (int *)shmat(smallestShmId, NULL, 0);
+
+  float per_process_raw = (float)VECT_SIZE / NUM_PROCESSES;
+  int per_process = (int)per_process_raw;
+
+  clock_t start, end;
+  double time_taken;
+
+  if (per_process_raw != (float)per_process) {
+    printf("Vector size of %d is not divisible by %d processes.\n", VECT_SIZE,
+           NUM_PROCESSES);
+    exit(-1);
+  }
+
+  srand(24601);
+  int i;
+
+  for (i = 0; i < VECT_SIZE; i++) {
+    vect[i] = rand();
+  }
+
+  for (i = 0; i < NUM_PROCESSES; i++) {
+    pid = fork();
+
+    if (pid == 0)
+      break;
+  }
+
+  int j;
+  int big = -INT_MAX;
+  int small = INT_MAX;
+
+  if (pid == 0) {
+    int start = i * per_process;
+    int end = i * per_process + per_process;
+
+    for (j = start; j < end; j++) {
+      if (vect[j] > big)
+        big = vect[j];
+
+      if (vect[j] < small)
+        small = vect[j];
+    }
+    largest[i] = big;
+    smallest[i] = small;
+    reach_barrier();
+  } else {
+    reach_barrier();
+    start = clock();
+    for (j = 0; j < NUM_PROCESSES; j++) {
+      if (largest[j] > big)
+        big = largest[j];
+
+      if (smallest[j] < small)
+        small = smallest[j];
+    }
+    end = clock();
+    time_taken = ((double)end - start) / CLOCKS_PER_SEC;
+
+    printf("\nNumber of items: %d\n", VECT_SIZE);
+    printf("Smallest element is %d\n", small);
+    printf("Largest element is %d\n", big);
+    printf("Time taken is %3.2fs\n\n", time_taken);
+
+    // Clean up process table
+    for (j = 0; j < NUM_PROCESSES; j++)
+      wait(NULL);
+
+    destroy_barrier(pid);
+    shmdt(largest);
+    shmdt(smallest);
+    shmctl(largestShmId, IPC_RMID, 0);
+    shmctl(smallestShmId, IPC_RMID, 0);
+  }
+}

cs2106/labs/lab3/progs/part3/bigsmall.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <time.h>
+#include "config.h"
+
+// Sort through an array of VECT_SIZE integers
+
+int main() {
+    int vect[VECT_SIZE], i;
+    clock_t start, end;
+    double time_taken;
+
+    srand(24601);
+    for(i=0; i<VECT_SIZE; i++) {
+        vect[i] = rand();
+    }
+
+    // Now find smallest and largest
+    int smallest = INT_MAX;
+    int largest = -INT_MAX;
+    
+    start = clock();
+    for(i=0; i<VECT_SIZE; i++) {
+        if(vect[i] < smallest) {
+            smallest = vect[i];
+        }
+
+        if(vect[i] > largest) {
+            largest = vect[i];
+        }
+    }
+    end = clock();
+    time_taken = ((double) (end - start)) / CLOCKS_PER_SEC;
+
+    printf("\nNumber of items: %d\n", VECT_SIZE);
+    printf("Smallest element is %d\n", smallest);
+    printf("Largest element is %d\n", largest);
+    printf("Time taken is %3.2f seconds\n\n", time_taken);
+}
+

cs2106/labs/lab3/progs/part3/config.h

@@ -0,0 +1,3 @@
+#define VECT_SIZE   2000000
+#define VECT_NAME   "vector.dat"
+