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/* Simple speed tests for hashtables. */
#include <ccan/htable/htable_type.h>
#include <ccan/htable/htable.c>
#include <ccan/hash/hash.h>
#include <ccan/time/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.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 struct object *object, const unsigned int *key)
{
return object->key == *key;
}
HTABLE_DEFINE_TYPE(struct object, objkey, hash_obj, cmp, htable_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) {
assert((ht->table[i] & ht->perfect_bit)
== ht->perfect_bit);
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 timeabs *start,
const struct timeabs *stop,
unsigned int num)
{
return time_to_nsec(time_divide(time_between(*stop, *start), num));
}
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;
unsigned int i, j;
size_t num, deleted;
struct timeabs start, stop;
struct htable_obj ht;
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];
}
htable_obj_init(&ht);
printf("Initial insert: ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++)
htable_obj_add(&ht, objs[i].self);
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Details: hash size %u, mask bits %u, perfect %.0f%%\n",
1U << ht.raw.bits, popcount(ht.raw.common_mask),
perfect(&ht.raw) * 100.0 / ht.raw.elems);
if (make_dumb) {
/* Screw with mask, to hobble us. */
update_common(&ht.raw, (void *)~ht.raw.common_bits);
printf("Details: DUMB MODE: mask bits %u\n",
popcount(ht.raw.common_mask));
}
printf("Initial lookup (match): ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++)
if (htable_obj_get(&ht, &i)->self != objs[i].self)
abort();
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Initial lookup (miss): ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++) {
unsigned int n = i + num;
if (htable_obj_get(&ht, &n))
abort();
}
stop = time_now();
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);
start = time_now();
for (i = 0, j = 0; i < num; i++, j = (j + 10007) % num)
if (htable_obj_get(&ht, &j)->self != &objs[j])
abort();
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
hashcount = 0;
printf("Initial delete all: ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++)
if (!htable_obj_del(&ht, objs[i].self))
abort();
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Details: rehashes %zu\n", hashcount);
printf("Initial re-inserting: ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++)
htable_obj_add(&ht, objs[i].self);
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
hashcount = 0;
printf("Deleting first half: ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i+=2)
if (!htable_obj_del(&ht, objs[i].self))
abort();
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Details: rehashes %zu, delete markers %zu\n",
hashcount, count_deleted(&ht.raw));
printf("Adding (a different) half: ");
fflush(stdout);
for (i = 0; i < num; i+=2)
objs[i].key = num+i;
start = time_now();
for (i = 0; i < num; i+=2)
htable_obj_add(&ht, objs[i].self);
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Details: delete markers %zu, perfect %.0f%%\n",
count_deleted(&ht.raw), perfect(&ht.raw) * 100.0 / ht.raw.elems);
printf("Lookup after half-change (match): ");
fflush(stdout);
start = time_now();
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();
}
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Lookup after half-change (miss): ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++) {
unsigned int n = i + num * 2;
if (htable_obj_get(&ht, &n))
abort();
}
stop = time_now();
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);
}
start = time_now();
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();
}
stop = time_now();
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(&ht.raw), perfect(&ht.raw) * 100.0 / ht.raw.elems);
i = worst_run(&ht.raw, &deleted);
printf("Details: worst run %u (%zu deleted)\n", i, deleted);
printf("Lookup after churn & spread (match): ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++) {
unsigned int n = num * 5 + i * 9;
if (htable_obj_get(&ht, &n)->self != objs[i].self)
abort();
}
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Lookup after churn & spread (miss): ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i++) {
unsigned int n = num * (5 + 9) + i * 9;
if (htable_obj_get(&ht, &n))
abort();
}
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Lookup after churn & spread (random): ");
fflush(stdout);
start = time_now();
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();
}
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
hashcount = 0;
printf("Deleting half after churn & spread: ");
fflush(stdout);
start = time_now();
for (i = 0; i < num; i+=2)
if (!htable_obj_del(&ht, objs[i].self))
abort();
stop = time_now();
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;
start = time_now();
for (i = 0; i < num; i+=2)
htable_obj_add(&ht, objs[i].self);
stop = time_now();
printf(" %zu ns\n", normalize(&start, &stop, num));
printf("Details: delete markers %zu, perfect %.0f%%\n",
count_deleted(&ht.raw), perfect(&ht.raw) * 100.0 / ht.raw.elems);
return 0;
}
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