*
* Note: This is code uses synchronous atomic operations because that is all that x86 provides.
* Every atomic operation is also an implicit full memory barrier. The upshot is that it simplifies
- * the code a bit, but it won't be as fast as it could be on platforms like SPARC that provide
- * weaker operations which would still do the job.
+ * the code a bit, but it won't be as fast as it could be on platforms that provide weaker
+ * operations like and unfenced CAS which would still do the job.
*/
#include <stdio.h>
#define GET_PTR(x) ((void *)((x) & MASK(48))) // low-order 48 bits is a pointer to a nstring_t
typedef struct entry {
- uint64_t key;
- uint64_t val;
+ map_key_t key;
+ map_val_t val;
} entry_t;
typedef struct hti {
struct ht_iter {
hti_t * hti;
int64_t idx;
- uint64_t key;
- uint64_t val;
};
struct ht {
const datatype_t *key_type;
};
-static const uint64_t COPIED_VALUE = -1;
-static const uint64_t TOMBSTONE = STRIP_TAG(-1, TAG1);
+static const map_val_t COPIED_VALUE = -1;
+static const map_val_t TOMBSTONE = STRIP_TAG(-1, TAG1);
static const unsigned ENTRIES_PER_BUCKET = CACHE_LINE_SIZE/sizeof(entry_t);
static const unsigned ENTRIES_PER_COPY_CHUNK = CACHE_LINE_SIZE/sizeof(entry_t)*2;
//
// Record if the entry being returned is empty. Otherwise the caller will have to waste time
// re-comparing the keys to confirm that it did not lose a race to fill an empty entry.
-static volatile entry_t *hti_lookup (hti_t *hti, void *key, uint32_t key_hash, int *is_empty) {
+static volatile entry_t *hti_lookup (hti_t *hti, map_key_t key, uint32_t key_hash, int *is_empty) {
TRACE("h2", "hti_lookup(key %p in hti %p)", key, hti);
*is_empty = 0;
for (int j = 0; j < ENTRIES_PER_BUCKET; ++j) {
volatile entry_t *ent = bucket + ((ndx + j) & (ENTRIES_PER_BUCKET-1));
- uint64_t ent_key = ent->key;
+ map_key_t ent_key = ent->key;
if (ent_key == DOES_NOT_EXIST) {
TRACE("h1", "hti_lookup: entry %p for key %p is empty", ent,
(hti->ht->key_type == NULL) ? (void *)ent_key : GET_PTR(ent_key));
// Compare <key> with the key in the entry.
if (EXPECT_TRUE(hti->ht->key_type == NULL)) {
// fast path for integer keys
- if (ent_key == (uint64_t)key) {
+ if (ent_key == key) {
TRACE("h1", "hti_lookup: found entry %p with key %p", ent, ent_key);
return ent;
}
// The key in <ent> is made up of two parts. The 48 low-order bits are a pointer. The
// high-order 16 bits are taken from the hash. The bits from the hash are used as a
// quick check to rule out non-equal keys without doing a complete compare.
- if ((key_hash >> 16) == (ent_key >> 48) && hti->ht->key_type->cmp(GET_PTR(ent_key), key) == 0) {
- TRACE("h1", "hti_lookup: found entry %p with key %p", ent, GET_PTR(ent_key));
- return ent;
+ if ((key_hash >> 16) == (ent_key >> 48)) {
+ if (hti->ht->key_type->cmp(GET_PTR(ent_key), (void *)key) == 0) {
+ TRACE("h1", "hti_lookup: found entry %p with key %p", ent, GET_PTR(ent_key));
+ return ent;
+ }
}
}
}
TRACE("h0", "hti_start_copy(hti %p scale %llu)", hti, hti->scale);
// heuristics to determine the size of the new table
- uint64_t count = ht_count(hti->ht);
+ size_t count = ht_count(hti->ht);
unsigned int new_scale = hti->scale;
new_scale += (count > (1 << (new_scale - 2))); // double size if more than 1/4 full
new_scale += (count > (1 << (new_scale - 2))); // double size again if more than 1/2 full
assert(ht1_ent >= ht1->table && ht1_ent < ht1->table + (1 << ht1->scale));
assert(key_hash == 0 || ht1->ht->key_type == NULL || (key_hash >> 16) == (ht1_ent->key >> 48));
- uint64_t ht1_ent_val = ht1_ent->val;
+ map_val_t ht1_ent_val = ht1_ent->val;
if (EXPECT_FALSE(ht1_ent_val == COPIED_VALUE)) {
TRACE("h1", "hti_copy_entry: entry %p already copied to table %p", ht1_ent, ht2);
return FALSE; // already copied
// Kill empty entries.
if (EXPECT_FALSE(ht1_ent_val == DOES_NOT_EXIST)) {
- uint64_t ht1_ent_val = SYNC_CAS(&ht1_ent->val, DOES_NOT_EXIST, COPIED_VALUE);
+ map_val_t ht1_ent_val = SYNC_CAS(&ht1_ent->val, DOES_NOT_EXIST, COPIED_VALUE);
if (ht1_ent_val == DOES_NOT_EXIST) {
TRACE("h1", "hti_copy_entry: empty entry %p killed", ht1_ent, 0);
return TRUE;
}
// Install the key in the new table.
- uint64_t ht1_ent_key = ht1_ent->key;
- void *key = (ht1->ht->key_type == NULL) ? (void *)ht1_ent_key : GET_PTR(ht1_ent_key);
+ map_key_t ht1_ent_key = ht1_ent->key;
+ map_key_t key = (ht1->ht->key_type == NULL) ? (map_key_t)ht1_ent_key : (map_key_t)GET_PTR(ht1_ent_key);
// The old table's dead entries don't need to be copied to the new table, but their keys need to be freed.
assert(COPIED_VALUE == TAG_VALUE(TOMBSTONE, TAG1));
if (ht1_ent_val == TOMBSTONE) {
TRACE("h1", "hti_copy_entry: entry %p old value was deleted, now freeing key %p", ht1_ent, key);
if (EXPECT_FALSE(ht1->ht->key_type != NULL)) {
- nbd_defer_free(key);
+ nbd_defer_free((void *)key);
}
return TRUE;
}
// We use 0 to indicate that <key_hash> is uninitiallized. Occasionally the key's hash will really be 0 and we
// waste time recomputing it every time. It is rare enough (1 in 65k) that it won't hurt performance.
if (key_hash == 0) {
- key_hash = (ht1->ht->key_type == NULL) ? murmur32_8b(ht1_ent_key) : ht1->ht->key_type->hash(key);
+ key_hash = (ht1->ht->key_type == NULL)
+ ? murmur32_8b(ht1_ent_key)
+ : ht1->ht->key_type->hash((void *)key);
}
int ht2_ent_is_empty;
}
if (ht2_ent_is_empty) {
- uint64_t old_ht2_ent_key = SYNC_CAS(&ht2_ent->key, DOES_NOT_EXIST, ht1_ent_key);
+ map_key_t old_ht2_ent_key = SYNC_CAS(&ht2_ent->key, DOES_NOT_EXIST, ht1_ent_key);
if (old_ht2_ent_key != DOES_NOT_EXIST) {
TRACE("h0", "hti_copy_entry: lost race to CAS key %p into new entry; found %p",
ht1_ent_key, old_ht2_ent_key);
// Copy the value to the entry in the new table.
ht1_ent_val = STRIP_TAG(ht1_ent_val, TAG1);
- uint64_t old_ht2_ent_val = SYNC_CAS(&ht2_ent->val, DOES_NOT_EXIST, ht1_ent_val);
+ map_val_t old_ht2_ent_val = SYNC_CAS(&ht2_ent->val, DOES_NOT_EXIST, ht1_ent_val);
// If there is a nested copy in progress, we might have installed the key into a dead entry.
if (old_ht2_ent_val == COPIED_VALUE) {
// real value matches (i.ent. not a TOMBSTONE or DOES_NOT_EXIST) as long as <key> is in the table. If
// <expected> is CAS_EXPECT_WHATEVER then skip the test entirely.
//
-static uint64_t hti_cas (hti_t *hti, void *key, uint32_t key_hash, uint64_t expected, uint64_t new) {
+static map_val_t hti_cas (hti_t *hti, map_key_t key, uint32_t key_hash, map_val_t expected, map_val_t new) {
TRACE("h1", "hti_cas: hti %p key %p", hti, key);
TRACE("h1", "hti_cas: value %p expect %p", new, expected);
assert(hti);
return DOES_NOT_EXIST;
// Allocate <new_key>.
- uint64_t new_key = (uint64_t)((hti->ht->key_type == NULL) ? key : hti->ht->key_type->clone(key));
+ map_key_t new_key = (hti->ht->key_type == NULL)
+ ? (map_key_t)key
+ : (map_key_t)hti->ht->key_type->clone((void *)key);
if (EXPECT_FALSE(hti->ht->key_type != NULL)) {
// Combine <new_key> pointer with bits from its hash
new_key = ((uint64_t)(key_hash >> 16) << 48) | new_key;
}
// CAS the key into the table.
- uint64_t old_ent_key = SYNC_CAS(&ent->key, DOES_NOT_EXIST, new_key);
+ map_key_t old_ent_key = SYNC_CAS(&ent->key, DOES_NOT_EXIST, new_key);
// Retry if another thread stole the entry out from under us.
if (old_ent_key != DOES_NOT_EXIST) {
(hti->ht->key_type == NULL) ? (void *)ent->key : GET_PTR(ent->key), ent);
// If the entry is in the middle of a copy, the copy must be completed first.
- uint64_t ent_val = ent->val;
+ map_val_t ent_val = ent->val;
if (EXPECT_FALSE(IS_TAGGED(ent_val, TAG1))) {
if (ent_val != COPIED_VALUE) {
int did_copy = hti_copy_entry(hti, ent, key_hash, ((volatile hti_t *)hti)->next);
}
// CAS the value into the entry. Retry if it fails.
- uint64_t v = SYNC_CAS(&ent->val, ent_val, new == DOES_NOT_EXIST ? TOMBSTONE : new);
+ map_val_t v = SYNC_CAS(&ent->val, ent_val, new == DOES_NOT_EXIST ? TOMBSTONE : new);
if (EXPECT_FALSE(v != ent_val)) {
TRACE("h0", "hti_cas: value CAS failed; expected %p found %p", ent_val, v);
return hti_cas(hti, key, key_hash, expected, new); // recursive tail-call
}
//
-static uint64_t hti_get (hti_t *hti, void *key, uint32_t key_hash) {
+static map_val_t hti_get (hti_t *hti, map_key_t key, uint32_t key_hash) {
int is_empty;
volatile entry_t *ent = hti_lookup(hti, key, key_hash, &is_empty);
return DOES_NOT_EXIST;
// If the entry is being copied, finish the copy and retry on the next table.
- uint64_t ent_val = ent->val;
+ map_val_t ent_val = ent->val;
if (EXPECT_FALSE(IS_TAGGED(ent_val, TAG1))) {
if (EXPECT_FALSE(ent_val != COPIED_VALUE)) {
int did_copy = hti_copy_entry(hti, ent, key_hash, ((volatile hti_t *)hti)->next);
}
//
-uint64_t ht_get (hashtable_t *ht, void *key) {
- uint32_t hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash(key);
+map_val_t ht_get (hashtable_t *ht, map_key_t key) {
+ uint32_t hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash((void *)key);
return hti_get(ht->hti, key, hash);
}
// returns TRUE if copy is done
int hti_help_copy (hti_t *hti) {
volatile entry_t *ent;
- uint64_t limit;
- uint64_t total_copied = hti->num_entries_copied;
- int num_copied = 0;
- int x = hti->copy_scan;
+ size_t limit;
+ size_t total_copied = hti->num_entries_copied;
+ size_t num_copied = 0;
+ size_t x = hti->copy_scan;
TRACE("h1", "ht_cas: help copy. scan is %llu, size is %llu", x, 1<<hti->scale);
if (total_copied != (1 << hti->scale)) {
}
//
-uint64_t ht_cas (hashtable_t *ht, void *key, uint64_t expected_val, uint64_t new_val) {
+map_val_t ht_cas (hashtable_t *ht, map_key_t key, map_val_t expected_val, map_val_t new_val) {
TRACE("h2", "ht_cas: key %p ht %p", key, ht);
TRACE("h2", "ht_cas: expected val %p new val %p", expected_val, new_val);
}
}
- uint64_t old_val;
- uint32_t key_hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash(key);
+ map_val_t old_val;
+ uint32_t key_hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash((void *)key);
while ((old_val = hti_cas(hti, key, key_hash, expected_val, new_val)) == COPIED_VALUE) {
assert(hti->next);
hti = hti->next;
// Remove the value in <ht> associated with <key>. Returns the value removed, or DOES_NOT_EXIST if there was
// no value for that key.
-uint64_t ht_remove (hashtable_t *ht, void *key) {
+map_val_t ht_remove (hashtable_t *ht, map_key_t key) {
hti_t *hti = ht->hti;
- uint64_t val;
- uint32_t key_hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash(key);
+ map_val_t val;
+ uint32_t key_hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash((void *)key);
do {
val = hti_cas(hti, key, key_hash, CAS_EXPECT_WHATEVER, DOES_NOT_EXIST);
if (val != COPIED_VALUE)
}
// Returns the number of key-values pairs in <ht>
-uint64_t ht_count (hashtable_t *ht) {
+size_t ht_count (hashtable_t *ht) {
hti_t *hti = ht->hti;
- uint64_t count = 0;
+ size_t count = 0;
while (hti) {
count += hti->count;
hti = hti->next;
printf("hti:%p scale:%u count:%d copied:%d\n", hti, hti->scale, hti->count, hti->num_entries_copied);
for (int i = 0; i < (1 << hti->scale); ++i) {
volatile entry_t *ent = hti->table + i;
- printf("[0x%x] %p:%p\n", i, (void *)ent->key, (void *)ent->val);
+ printf("[0x%x] 0x%llx:0x%llx\n", i, (uint64_t)ent->key, ent->val);
if (i > 30) {
printf("...\n");
break;
}
}
-ht_iter_t *ht_iter_begin (hashtable_t *ht, void *key) {
- assert(key == NULL);
+ht_iter_t *ht_iter_begin (hashtable_t *ht, map_key_t key) {
hti_t *hti = ht->hti;
int rcount;
do {
return iter;
}
-uint64_t ht_iter_next (ht_iter_t *iter, void **key_ptr) {
+map_val_t ht_iter_next (ht_iter_t *iter, map_key_t *key_ptr) {
volatile entry_t *ent;
- uint64_t key;
- uint64_t val;
- uint64_t table_size = (1 << iter->hti->scale);
+ map_key_t key;
+ map_val_t val;
+ size_t table_size = (1 << iter->hti->scale);
do {
iter->idx++;
if (iter->idx == table_size) {
return DOES_NOT_EXIST;
}
ent = &iter->hti->table[iter->idx];
- key = ent->key;
+ key = (iter->hti->ht->key_type == NULL) ? (map_key_t)ent->key : (map_key_t)GET_PTR(ent->key);
val = ent->val;
} while (key == DOES_NOT_EXIST || val == DOES_NOT_EXIST || val == TOMBSTONE);
if (key_ptr) {
- *key_ptr = (void *)key;
+ *key_ptr = key;
}
if (val == COPIED_VALUE) {
uint32_t hash = (iter->hti->ht->key_type == NULL)
- ? murmur32_8b(key)
+ ? murmur32_8b((uint64_t)key)
: iter->hti->ht->key_type->hash((void *)key);
- val = hti_get(iter->hti->next, (void *)ent->key, hash);
+ val = hti_get(iter->hti->next, (map_key_t)ent->key, hash);
}
return val;
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