Initial commit

Author: mattbford

Diff for: .gitattributes

@@ -0,0 +1,2 @@
+# Auto detect text files and perform LF normalization
+* text=auto

Diff for: pc_mutex_cond_pthread.c

@@ -0,0 +1,86 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <assert.h>
+
+#define MAX_ITEMS 10
+const int NUM_ITERATIONS = 200;
+const int NUM_CONSUMERS  = 2;
+const int NUM_PRODUCERS  = 2;
+
+int producer_wait_count;     // # of times producer had to wait
+int consumer_wait_count;     // # of times consumer had to wait
+int histogram [MAX_ITEMS+1]; // histogram [i] == # of times list stored i items
+
+pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_cond_t condc, condp;
+
+int items = 0;
+
+void* producer (void* v) {
+  for (int i=0; i<NUM_ITERATIONS; i++) {
+    // protects buffer from over-production
+    pthread_mutex_lock(&mutex);
+    if(items >= MAX_ITEMS) {
+      while(items >= MAX_ITEMS) {
+        pthread_cond_wait(&condp, &mutex);
+      }
+      producer_wait_count++;
+    }
+
+    //PRODUCE
+    items++;
+    histogram[items]++;
+    //give greenlight to consume
+    pthread_cond_signal(&condc);
+    pthread_mutex_unlock(&mutex);
+
+  }
+  return NULL;
+}
+
+void* consumer (void* v) {
+  for (int i=0; i<NUM_ITERATIONS; i++) {
+    // protects buffer from over-consumption
+    pthread_mutex_lock(&mutex);
+    if(items <= 0 ) {
+      while(items <= 0) {
+        pthread_cond_wait(&condc, &mutex);
+      }
+      consumer_wait_count++;
+    }
+    //CONSUME
+    items--;
+    histogram[items]++;
+    //give greenlight to produce
+    pthread_cond_signal(&condp);
+    pthread_mutex_unlock(&mutex);
+  }
+  return NULL;
+}
+
+int main (int argc, char** argv) {
+  pthread_t t[4];
+
+  // Create Threads and Join
+  pthread_create(&t[0], NULL, producer, NULL);
+  pthread_create(&t[1], NULL, producer, NULL);
+  pthread_create(&t[2], NULL, consumer, NULL);
+  pthread_create(&t[3], NULL, consumer, NULL);
+
+  pthread_join(t[0], NULL);
+  pthread_join(t[1], NULL);
+  pthread_join(t[2], NULL);
+  pthread_join(t[3], NULL);
+
+  printf ("producer_wait_count=%d\nconsumer_wait_count=%d\n", producer_wait_count, consumer_wait_count);
+  printf ("items value histogram:\n");
+  int sum=0;
+  for (int i = 0; i <= MAX_ITEMS; i++) {
+    printf ("  items=%d, %d times\n", i, histogram [i]);
+    sum += histogram [i];
+  }
+  printf("sum: %d\n", sum);
+  assert (sum == sizeof (t) / sizeof (pthread_t) * NUM_ITERATIONS);
+}

Diff for: pc_sem_pthread.c

@@ -0,0 +1,89 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <unistd.h>
+
+#define MAX_ITEMS 10
+const int NUM_ITERATIONS = 200;
+const int NUM_CONSUMERS  = 2;
+const int NUM_PRODUCERS  = 2;
+
+int histogram [MAX_ITEMS+1]; // histogram [i] == # of times list stored i items
+sem_t sem_empty;
+sem_t sem_full;
+sem_t avail;
+
+int items = 0;
+
+void* producer (void* v) {
+  for (int i=0; i<NUM_ITERATIONS; i++) {
+
+    sem_wait(&sem_empty);
+    sem_wait(&avail);
+
+    printf("-");
+    items++;
+    histogram[items]++;
+    sem_post(&avail);
+    if(items >= MAX_ITEMS)
+      sem_post(&sem_full);
+    else
+      sem_post(&sem_empty);
+
+  }
+  return NULL;
+}
+
+void* consumer (void* v) {
+  for (int i=0; i<NUM_ITERATIONS; i++) {
+
+    sem_wait(&sem_full);
+    sem_wait(&avail);
+
+    printf("_");
+    items--;
+    histogram[items]++;
+    sem_post(&avail);
+    if(items <= 0)
+      sem_post(&sem_empty);
+    else
+      sem_post(&sem_full);
+
+  }
+  return NULL;
+}
+
+int main (int argc, char** argv) {
+  pthread_t t[4];
+
+  sem_init(&sem_empty, 0, 1);
+  sem_init(&sem_full, 0, 0);
+  sem_init(&avail, 0, 1);
+
+  // Create Threads and Join
+  pthread_create(&t[0], NULL, producer, NULL);
+  pthread_create(&t[1], NULL, producer, NULL);
+  pthread_create(&t[2], NULL, consumer, NULL);
+  pthread_create(&t[3], NULL, consumer, NULL);
+
+  pthread_join(t[0], NULL);
+  pthread_join(t[1], NULL);
+  pthread_join(t[2], NULL);
+  pthread_join(t[3], NULL);
+
+  printf ("items value histogram:\n");
+  int sum=0;
+  for (int i = 0; i <= MAX_ITEMS; i++) {
+    printf ("  items=%d, %d times\n", i, histogram [i]);
+    sum += histogram [i];
+  }
+  printf("sum: %d\n", sum);
+  assert (sum == sizeof (t) / sizeof (pthread_t) * NUM_ITERATIONS);
+
+  sem_destroy(&sem_empty);
+  sem_destroy(&sem_full);
+  sem_destroy(&avail);
+
+}