added multithreading sync/memory examples

1 files changed, 123 insertions, 0 deletions

diff --git a/parallel/cig_smoker_problem.c b/parallel/cig_smoker_problem.c
new file mode 100644
index 0000000..9d0928b
--- /dev/null
+++ b/parallel/cig_smoker_problem.c
@@ -0,0 +1,123 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <pthread.h>
+#include <semaphore.h>
+
+#include <assert.h>
+
+
+enum thrd_ids {
+  AGENT_A = 0,
+  AGENT_B,
+  AGENT_C,
+  SMOKER_T,
+  SMOKER_P,
+  SMOKER_M,
+  THRD_MAX
+};
+
+static pthread_t thrds[THRD_MAX];
+
+enum sem_ids {
+  AGENTSEM = 0,
+  TOBACCO,
+  PAPER,
+  MATCH,
+  SEM_MAX
+};
+
+static sem_t sems[SEM_MAX];
+
+
+static void *agenta_thread(void *args)
+{
+  while (1) {
+    sem_wait(&sems[AGENTSEM]);
+    sem_post(&sems[TOBACCO]);
+    sem_post(&sems[PAPER]);
+    printf("AGENT_A: +1 TOBACCO , +1 PAPER\n");
+  }
+  return NULL;
+}
+
+static void *agentb_thread(void *args)
+{
+  while (1) {
+    sem_wait(&sems[AGENTSEM]);
+    sem_post(&sems[PAPER]);
+    sem_post(&sems[MATCH]);
+    printf("AGENT_B: +1 PAPER, +1 MATCH\n");
+  }
+  return NULL;
+}
+
+static void *agentc_thread(void *args)
+{
+  while (1) {
+    sem_wait(&sems[AGENTSEM]);
+    sem_post(&sems[TOBACCO]);
+    sem_post(&sems[MATCH]);
+    printf("AGENT_C: +1 TOBACCO, +1 MATCH\n");
+  }
+  return NULL;
+}
+
+static void *smokerm_thread(void *args)
+{
+  while (1) {
+    sem_wait(&sems[TOBACCO]);
+    sem_wait(&sems[PAPER]);
+    sem_post(&sems[AGENTSEM]);
+    printf("SMOKER_M: +1 PAPER , \n");
+  }
+  return NULL;
+}
+
+static void *smokert_thread(void *args)
+{
+  while (1) {
+    sem_wait(&sems[PAPER]);
+    sem_wait(&sems[MATCH]);
+    sem_post(&sems[AGENTSEM]);
+    printf("SMOKER_T\n");
+  }
+  return NULL;
+}
+
+static void *smokerp_thread(void *args)
+{
+  while (1) {
+    sem_wait(&sems[TOBACCO]);
+    sem_wait(&sems[MATCH]);
+    sem_post(&sems[AGENTSEM]);
+    printf("SMOKER_P\n");
+  }
+  return NULL;
+}
+
+int
+main(int argc, char *argv[])
+{
+  int i;
+
+  for (i = 0; i < SEM_MAX; i++) {
+    assert( sem_init(&sems[i], 0, 0) == 0 );
+  }
+
+  assert( pthread_create(&thrds[AGENT_A], NULL, agenta_thread, NULL) == 0 );
+  assert( pthread_create(&thrds[AGENT_B], NULL, agentb_thread, NULL) == 0 );
+  assert( pthread_create(&thrds[AGENT_C], NULL, agentc_thread, NULL) == 0 );
+  assert( pthread_create(&thrds[SMOKER_M], NULL, smokerm_thread, NULL) == 0 );
+  assert( pthread_create(&thrds[SMOKER_T], NULL, smokert_thread, NULL) == 0 );
+  assert( pthread_create(&thrds[SMOKER_P], NULL, smokerp_thread, NULL) == 0 );
+
+  while (1) {
+    sleep( random() % 5 );
+    sem_post(&sems[AGENTSEM]);
+  }
+  return 0;
+}
+
+