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-rw-r--r--notxv6/ph.c150
1 files changed, 150 insertions, 0 deletions
diff --git a/notxv6/ph.c b/notxv6/ph.c
new file mode 100644
index 0000000..82afe76
--- /dev/null
+++ b/notxv6/ph.c
@@ -0,0 +1,150 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <assert.h>
+#include <pthread.h>
+#include <sys/time.h>
+
+#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;
+
+
+double
+now()
+{
+ struct timeval tv;
+ gettimeofday(&tv, 0);
+ return tv.tv_sec + tv.tv_usec / 1000000.0;
+}
+
+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;
+
+ // is the key already present?
+ struct entry *e = 0;
+ for (e = table[i]; e != 0; e = e->next) {
+ if (e->key == key)
+ break;
+ }
+ if(e){
+ // update the existing key.
+ e->value = value;
+ } else {
+ // the new is new.
+ insert(key, value, &table[i], table[i]);
+ }
+
+}
+
+static struct entry*
+get(int key)
+{
+ int i = key % NBUCKET;
+
+
+ struct entry *e = 0;
+ for (e = table[i]; e != 0; e = e->next) {
+ if (e->key == key) break;
+ }
+
+ return e;
+}
+
+static void *
+put_thread(void *xa)
+{
+ int n = (int) (long) xa; // thread number
+ int b = NKEYS/nthread;
+
+ for (int i = 0; i < b; i++) {
+ put(keys[b*n + i], n);
+ }
+
+ return NULL;
+}
+
+static void *
+get_thread(void *xa)
+{
+ int n = (int) (long) xa; // thread number
+ int missing = 0;
+
+ for (int i = 0; i < NKEYS; i++) {
+ struct entry *e = get(keys[i]);
+ if (e == 0) missing++;
+ }
+ printf("%d: %d keys missing\n", n, missing);
+ return NULL;
+}
+
+int
+main(int argc, char *argv[])
+{
+ pthread_t *tha;
+ void *value;
+ double t1, t0;
+
+
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s nthreads\n", argv[0]);
+ exit(-1);
+ }
+ nthread = atoi(argv[1]);
+ tha = malloc(sizeof(pthread_t) * nthread);
+ srandom(0);
+ assert(NKEYS % nthread == 0);
+ for (int i = 0; i < NKEYS; i++) {
+ keys[i] = random();
+ }
+
+ //
+ // first the puts
+ //
+ t0 = now();
+ for(int i = 0; i < nthread; i++) {
+ assert(pthread_create(&tha[i], NULL, put_thread, (void *) (long) i) == 0);
+ }
+ for(int i = 0; i < nthread; i++) {
+ assert(pthread_join(tha[i], &value) == 0);
+ }
+ t1 = now();
+
+ printf("%d puts, %.3f seconds, %.0f puts/second\n",
+ NKEYS, t1 - t0, NKEYS / (t1 - t0));
+
+ //
+ // now the gets
+ //
+ t0 = now();
+ for(int i = 0; i < nthread; i++) {
+ assert(pthread_create(&tha[i], NULL, get_thread, (void *) (long) i) == 0);
+ }
+ for(int i = 0; i < nthread; i++) {
+ assert(pthread_join(tha[i], &value) == 0);
+ }
+ t1 = now();
+
+ printf("%d gets, %.3f seconds, %.0f gets/second\n",
+ NKEYS*nthread, t1 - t0, (NKEYS*nthread) / (t1 - t0));
+}