HW5 threads + locking: add ph.c file

hw/ph.c

@@ -0,0 +1,133 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <assert.h>
+#include <pthread.h>
+#include <sys/time.h>
+
+#define SOL
+#define NBUCKET 5
+#define NKEYS 100000
+
+struct entry {
+  int key;
+  int value;
+  struct entry *next;
+};
+struct entry *table[NBUCKET];
+int keys[NKEYS];
+int nthread = 1;
+volatile int done;
+
+
+double
+now()
+{
+ struct timeval tv;
+ gettimeofday(&tv, 0);
+ return tv.tv_sec + tv.tv_usec / 1000000.0;
+}
+
+static void
+print(void)
+{
+  int i;
+  struct entry *e;
+  for (i = 0; i < NBUCKET; i++) {
+    printf("%d: ", i);
+    for (e = table[i]; e != 0; e = e->next) {
+      printf("%d ", e->key);
+    }
+    printf("\n");
+  }
+}
+
+static void
+insert(int key, int value, struct entry **p, struct entry *n)
+{
+  struct entry *e = malloc(sizeof(struct entry));
+  e->key = key;
+  e->value = value;
+  e->next = n;
+  *p = e;
+}
+
+static
+void put(int key, int value)
+{
+  int i = key % NBUCKET;
+  insert(key, value, &table[i], table[i]);
+}
+
+static struct entry*
+get(int key)
+{
+  struct entry *e = 0;
+  for (e = table[key % NBUCKET]; e != 0; e = e->next) {
+    if (e->key == key) break;
+  }
+  return e;
+}
+
+static void *
+thread(void *xa)
+{
+  long n = (long) xa;
+  int i;
+  int b = NKEYS/nthread;
+  int k = 0;
+  double t1, t0;
+
+  //  printf("b = %d\n", b);
+  t0 = now();
+  for (i = 0; i < b; i++) {
+    // printf("%d: put %d\n", n, b*n+i);
+    put(keys[b*n + i], n);
+  }
+  t1 = now();
+  printf("%ld: put time = %f\n", n, t1-t0);
+
+  // Should use pthread_barrier, but MacOS doesn't support it ...
+  __sync_fetch_and_add(&done, 1);
+  while (done < nthread) ;
+
+  t0 = now();
+  for (i = 0; i < NKEYS; i++) {
+    struct entry *e = get(keys[i]);
+    if (e == 0) k++;
+  }
+  t1 = now();
+  printf("%ld: get time = %f\n", n, t1-t0);
+  printf("%ld: %d keys missing\n", n, k);
+  return NULL;
+}
+
+int
+main(int argc, char *argv[])
+{
+  pthread_t *tha;
+  void *value;
+  long i;
+  double t1, t0;
+
+  if (argc < 2) {
+    fprintf(stderr, "%s: %s nthread\n", argv[0], argv[0]);
+    exit(-1);
+  }
+  nthread = atoi(argv[1]);
+  tha = malloc(sizeof(pthread_t) * nthread);
+  srandom(0);
+  assert(NKEYS % nthread == 0);
+  for (i = 0; i < NKEYS; i++) {
+    keys[i] = random();
+  }
+  t0 = now();
+  for(i = 0; i < nthread; i++) {
+    assert(pthread_create(&tha[i], NULL, thread, (void *) i) == 0);
+  }
+  for(i = 0; i < nthread; i++) {
+    assert(pthread_join(tha[i], &value) == 0);
+  }
+  t1 = now();
+  printf("completion time = %f\n", t1-t0);
+}