+/* Simple speed tests for hashtables. */
+#include <ccan/htable/htable_type.h>
+#include <ccan/htable/htable.c>
+#include <ccan/hash/hash.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+static size_t hashcount;
+struct object {
+ /* The key. */
+ unsigned int key;
+
+ /* Some contents. Doubles as consistency check. */
+ struct object *self;
+};
+
+static const unsigned int *objkey(const struct object *obj)
+{
+ return &obj->key;
+}
+
+static size_t hash_obj(const unsigned int *key)
+{
+ hashcount++;
+ return hashl(key, 1, 0);
+}
+
+static bool cmp(const unsigned int *key1, const unsigned int *key2)
+{
+ return *key1 == *key2;
+}
+
+HTABLE_DEFINE_TYPE(struct object, objkey, hash_obj, cmp, obj);
+
+static unsigned int popcount(unsigned long val)
+{
+#if HAVE_BUILTIN_POPCOUNTL
+ return __builtin_popcountl(val);
+#else
+ if (sizeof(long) == sizeof(u64)) {
+ u64 v = val;
+ v = (v & 0x5555555555555555ULL)
+ + ((v >> 1) & 0x5555555555555555ULL);
+ v = (v & 0x3333333333333333ULL)
+ + ((v >> 1) & 0x3333333333333333ULL);
+ v = (v & 0x0F0F0F0F0F0F0F0FULL)
+ + ((v >> 1) & 0x0F0F0F0F0F0F0F0FULL);
+ v = (v & 0x00FF00FF00FF00FFULL)
+ + ((v >> 1) & 0x00FF00FF00FF00FFULL);
+ v = (v & 0x0000FFFF0000FFFFULL)
+ + ((v >> 1) & 0x0000FFFF0000FFFFULL);
+ v = (v & 0x00000000FFFFFFFFULL)
+ + ((v >> 1) & 0x00000000FFFFFFFFULL);
+ return v;
+ }
+ val = (val & 0x55555555ULL) + ((val >> 1) & 0x55555555ULL);
+ val = (val & 0x33333333ULL) + ((val >> 1) & 0x33333333ULL);
+ val = (val & 0x0F0F0F0FULL) + ((val >> 1) & 0x0F0F0F0FULL);
+ val = (val & 0x00FF00FFULL) + ((val >> 1) & 0x00FF00FFULL);
+ val = (val & 0x0000FFFFULL) + ((val >> 1) & 0x0000FFFFULL);
+ return val;
+#endif
+}
+
+static size_t perfect(const struct htable *ht)
+{
+ size_t i, placed_perfect = 0;
+
+ for (i = 0; i < ((size_t)1 << ht->bits); i++) {
+ if (!entry_is_valid(ht->table[i]))
+ continue;
+ if (hash_bucket(ht, ht->rehash(get_raw_ptr(ht, ht->table[i]),
+ ht->priv)) == i)
+ placed_perfect++;
+ }
+ return placed_perfect;
+}
+
+static size_t count_deleted(const struct htable *ht)
+{
+ size_t i, delete_markers = 0;
+
+ for (i = 0; i < ((size_t)1 << ht->bits); i++) {
+ if (ht->table[i] == HTABLE_DELETED)
+ delete_markers++;
+ }
+ return delete_markers;
+}
+
+/* Nanoseconds per operation */
+static size_t normalize(const struct timeval *start,
+ const struct timeval *stop,
+ unsigned int num)
+{
+ struct timeval diff;
+
+ timersub(stop, start, &diff);
+
+ /* Floating point is more accurate here. */
+ return (double)(diff.tv_sec * 1000000 + diff.tv_usec)
+ / num * 1000;
+}
+
+static size_t worst_run(struct htable *ht, size_t *deleted)
+{
+ size_t longest = 0, len = 0, this_del = 0, i;
+
+ *deleted = 0;
+ /* This doesn't take into account end-wrap, but gives an idea. */
+ for (i = 0; i < ((size_t)1 << ht->bits); i++) {
+ if (ht->table[i]) {
+ len++;
+ if (ht->table[i] == HTABLE_DELETED)
+ this_del++;
+ } else {
+ if (len > longest) {
+ longest = len;
+ *deleted = this_del;
+ }
+ len = 0;
+ this_del = 0;
+ }
+ }
+ return longest;
+}
+
+int main(int argc, char *argv[])
+{
+ struct object *objs;
+ size_t i, j, num, deleted;
+ struct timeval start, stop;
+ struct htable_obj *ht;
+ struct htable *htr;
+ bool make_dumb = false;
+
+ if (argv[1] && strcmp(argv[1], "--dumb") == 0) {
+ argv++;
+ make_dumb = true;
+ }
+ num = argv[1] ? atoi(argv[1]) : 1000000;
+ objs = calloc(num, sizeof(objs[0]));
+
+ for (i = 0; i < num; i++) {
+ objs[i].key = i;
+ objs[i].self = &objs[i];
+ }
+
+ ht = htable_obj_new();
+ htr = (void *)ht;
+
+ printf("Initial insert: ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++)
+ htable_obj_add(ht, objs[i].self);
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+ printf("Details: hash size %u, mask bits %u, perfect %.0f%%\n",
+ 1U << htr->bits, popcount(htr->common_mask),
+ perfect(htr) * 100.0 / htr->elems);
+
+ if (make_dumb) {
+ /* Screw with mask, to hobble us. */
+ update_common(htr, (void *)~htr->common_bits);
+ printf("Details: DUMB MODE: mask bits %u\n",
+ popcount(htr->common_mask));
+ }
+
+ printf("Initial lookup (match): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++)
+ if (htable_obj_get(ht, &i)->self != objs[i].self)
+ abort();
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Initial lookup (miss): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++) {
+ unsigned int n = i + num;
+ if (htable_obj_get(ht, &n))
+ abort();
+ }
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ /* Lookups in order are very cache-friendly for judy; try random */
+ printf("Initial lookup (random): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0, j = 0; i < num; i++, j = (j + 10007) % num)
+ if (htable_obj_get(ht, &j)->self != &objs[j])
+ abort();
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ hashcount = 0;
+ printf("Initial delete all: ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++)
+ if (!htable_obj_del(ht, objs[i].self))
+ abort();
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+ printf("Details: rehashes %zu\n", hashcount);
+
+ printf("Initial re-inserting: ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++)
+ htable_obj_add(ht, objs[i].self);
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ hashcount = 0;
+ printf("Deleting first half: ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i+=2)
+ if (!htable_obj_del(ht, objs[i].self))
+ abort();
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Details: rehashes %zu, delete markers %zu\n",
+ hashcount, count_deleted(htr));
+
+ printf("Adding (a different) half: ");
+ fflush(stdout);
+
+ for (i = 0; i < num; i+=2)
+ objs[i].key = num+i;
+
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i+=2)
+ htable_obj_add(ht, objs[i].self);
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Details: delete markers %zu, perfect %.0f%%\n",
+ count_deleted(htr), perfect(htr) * 100.0 / htr->elems);
+
+ printf("Lookup after half-change (match): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 1; i < num; i+=2)
+ if (htable_obj_get(ht, &i)->self != objs[i].self)
+ abort();
+ for (i = 0; i < num; i+=2) {
+ unsigned int n = i + num;
+ if (htable_obj_get(ht, &n)->self != objs[i].self)
+ abort();
+ }
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Lookup after half-change (miss): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++) {
+ unsigned int n = i + num * 2;
+ if (htable_obj_get(ht, &n))
+ abort();
+ }
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ /* Hashtables with delete markers can fill with markers over time.
+ * so do some changes to see how it operates in long-term. */
+ for (i = 0; i < 5; i++) {
+ if (i == 0) {
+ /* We don't measure this: jmap is different. */
+ printf("Details: initial churn\n");
+ } else {
+ printf("Churning %s time: ",
+ i == 1 ? "second"
+ : i == 2 ? "third"
+ : i == 3 ? "fourth"
+ : "fifth");
+ fflush(stdout);
+ }
+ gettimeofday(&start, NULL);
+ for (j = 0; j < num; j++) {
+ if (!htable_obj_del(ht, &objs[j]))
+ abort();
+ objs[j].key = num*i+j;
+ if (!htable_obj_add(ht, &objs[j]))
+ abort();
+ }
+ gettimeofday(&stop, NULL);
+ if (i != 0)
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+ }
+
+ /* Spread out the keys more to try to make it harder. */
+ printf("Details: reinserting with spread\n");
+ for (i = 0; i < num; i++) {
+ if (!htable_obj_del(ht, objs[i].self))
+ abort();
+ objs[i].key = num * 5 + i * 9;
+ if (!htable_obj_add(ht, objs[i].self))
+ abort();
+ }
+ printf("Details: delete markers %zu, perfect %.0f%%\n",
+ count_deleted(htr), perfect(htr) * 100.0 / htr->elems);
+ i = worst_run(htr, &deleted);
+ printf("Details: worst run %zu (%zu deleted)\n", i, deleted);
+
+ printf("Lookup after churn & spread (match): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++) {
+ unsigned int n = num * 5 + i * 9;
+ if (htable_obj_get(ht, &n)->self != objs[i].self)
+ abort();
+ }
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Lookup after churn & spread (miss): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i++) {
+ unsigned int n = num * 6 + i * 9;
+ if (htable_obj_get(ht, &n))
+ abort();
+ }
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Lookup after churn & spread (random): ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0, j = 0; i < num; i++, j = (j + 10007) % num) {
+ unsigned int n = num * 5 + j * 9;
+ if (htable_obj_get(ht, &n)->self != &objs[j])
+ abort();
+ }
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ hashcount = 0;
+ printf("Deleting half after churn & spread: ");
+ fflush(stdout);
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i+=2)
+ if (!htable_obj_del(ht, objs[i].self))
+ abort();
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Adding (a different) half after churn & spread: ");
+ fflush(stdout);
+
+ for (i = 0; i < num; i+=2)
+ objs[i].key = num*6+i*9;
+
+ gettimeofday(&start, NULL);
+ for (i = 0; i < num; i+=2)
+ htable_obj_add(ht, objs[i].self);
+ gettimeofday(&stop, NULL);
+ printf(" %zu ns\n", normalize(&start, &stop, num));
+
+ printf("Details: delete markers %zu, perfect %.0f%%\n",
+ count_deleted(htr), perfect(htr) * 100.0 / htr->elems);
+
+ return 0;
+}
projects / ccan / commitdiff