htable, strset: benchmarking tools.

[ccan] / ccan / htable / htable.c

diff --git a/ccan/htable/htable.c b/ccan/htable/htable.c
index 48a734071fa93e1cca12a438c129c008ec0e72ee..20b6f5ae2dc964c521aa7f517912cd3d4ab9aa6c 100644 (file)
--- a/ccan/htable/htable.c
+++ b/ccan/htable/htable.c
@@ -1,7 +1,9 @@
+/* Licensed under LGPLv2+ - see LICENSE file for details */
 #include <ccan/htable/htable.h>
 #include <ccan/compiler/compiler.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <limits.h>
 #include <stdbool.h>
 #include <assert.h>
 
@@ -18,6 +20,7 @@ struct htable {
        size_t elems, deleted, max, max_with_deleted;
        /* These are the bits which are the same in all pointers. */
        uintptr_t common_mask, common_bits;
+       uintptr_t perfect_bit;
        uintptr_t *table;
 };
 
@@ -50,7 +53,8 @@ static inline uintptr_t get_hash_ptr_bits(const struct htable *ht,
        /* Shuffling the extra bits (as specified in mask) down the
         * end is quite expensive.  But the lower bits are redundant, so
         * we fold the value first. */
-       return (hash ^ (hash >> ht->bits)) & ht->common_mask;
+       return (hash ^ (hash >> ht->bits))
+               & ht->common_mask & ~ht->perfect_bit;
 }
 
 struct htable *htable_new(size_t (*rehash)(const void *elem, void *priv),
@@ -63,11 +67,12 @@ struct htable *htable_new(size_t (*rehash)(const void *elem, void *priv),
                ht->priv = priv;
                ht->elems = 0;
                ht->deleted = 0;
-               ht->max = (1 << ht->bits) * 2 / 3;
-               ht->max_with_deleted = (1 << ht->bits) * 4 / 5;
+               ht->max = ((size_t)1 << ht->bits) * 3 / 4;
+               ht->max_with_deleted = ((size_t)1 << ht->bits) * 9 / 10;
                /* This guarantees we enter update_common first add. */
                ht->common_mask = -1;
                ht->common_bits = 0;
+               ht->perfect_bit = 0;
                ht->table = calloc(1 << ht->bits, sizeof(uintptr_t));
                if (!ht->table) {
                        free(ht);
@@ -89,9 +94,9 @@ static size_t hash_bucket(const struct htable *ht, size_t h)
 }
 
 static void *htable_val(const struct htable *ht,
-                       struct htable_iter *i, size_t hash)
+                       struct htable_iter *i, size_t hash, uintptr_t perfect)
 {
-       uintptr_t h2 = get_hash_ptr_bits(ht, hash);
+       uintptr_t h2 = get_hash_ptr_bits(ht, hash) | perfect;
 
        while (ht->table[i->off]) {
                if (ht->table[i->off] != HTABLE_DELETED) {
@@ -99,6 +104,7 @@ static void *htable_val(const struct htable *ht,
                                return get_raw_ptr(ht, ht->table[i->off]);
                }
                i->off = (i->off + 1) & ((1 << ht->bits)-1);
+               h2 &= ~perfect;
        }
        return NULL;
 }
@@ -107,14 +113,14 @@ void *htable_firstval(const struct htable *ht,
                      struct htable_iter *i, size_t hash)
 {
        i->off = hash_bucket(ht, hash);
-       return htable_val(ht, i, hash);
+       return htable_val(ht, i, hash, ht->perfect_bit);
 }
 
 void *htable_nextval(const struct htable *ht,
                     struct htable_iter *i, size_t hash)
 {
        i->off = (i->off + 1) & ((1 << ht->bits)-1);
-       return htable_val(ht, i, hash);
+       return htable_val(ht, i, hash, 0);
 }
 
 void *htable_first(const struct htable *ht, struct htable_iter *i)
@@ -139,16 +145,18 @@ void *htable_next(const struct htable *ht, struct htable_iter *i)
 static void ht_add(struct htable *ht, const void *new, size_t h)
 {
        size_t i;
+       uintptr_t perfect = ht->perfect_bit;
 
        i = hash_bucket(ht, h);
 
-       while (entry_is_valid(ht->table[i]))
+       while (entry_is_valid(ht->table[i])) {
+               perfect = 0;
                i = (i + 1) & ((1 << ht->bits)-1);
-
-       ht->table[i] = make_hval(ht, new, get_hash_ptr_bits(ht, h));
+       }
+       ht->table[i] = make_hval(ht, new, get_hash_ptr_bits(ht, h)|perfect);
 }
 
-static COLD_ATTRIBUTE bool double_table(struct htable *ht)
+static COLD bool double_table(struct htable *ht)
 {
        unsigned int i;
        size_t oldnum = (size_t)1 << ht->bits;
@@ -164,6 +172,16 @@ static COLD_ATTRIBUTE bool double_table(struct htable *ht)
        ht->max *= 2;
        ht->max_with_deleted *= 2;
 
+       /* If we lost our "perfect bit", get it back now. */
+       if (!ht->perfect_bit && ht->common_mask) {
+               for (i = 0; i < sizeof(ht->common_mask) * CHAR_BIT; i++) {
+                       if (ht->common_mask & ((size_t)1 << i)) {
+                               ht->perfect_bit = (size_t)1 << i;
+                               break;
+                       }
+               }
+       }
+
        for (i = 0; i < oldnum; i++) {
                if (entry_is_valid(e = oldtable[i])) {
                        void *p = get_raw_ptr(ht, e);
@@ -175,7 +193,7 @@ static COLD_ATTRIBUTE bool double_table(struct htable *ht)
        return true;
 }
 
-static COLD_ATTRIBUTE void rehash_table(struct htable *ht)
+static COLD void rehash_table(struct htable *ht)
 {
        size_t start, i;
        uintptr_t e;
@@ -188,9 +206,11 @@ static COLD_ATTRIBUTE void rehash_table(struct htable *ht)
                e = ht->table[h];
                if (!e)
                        continue;
-               ht->table[h] = 0;
-               if (e != HTABLE_DELETED) {
+               if (e == HTABLE_DELETED)
+                       ht->table[h] = 0;
+               else if (!(e & ht->perfect_bit)) {
                        void *p = get_raw_ptr(ht, e);
+                       ht->table[h] = 0;
                        ht_add(ht, p, ht->rehash(p, ht->priv));
                }
        }
@@ -198,7 +218,7 @@ static COLD_ATTRIBUTE void rehash_table(struct htable *ht)
 }
 
 /* We stole some bits, now we need to put them back... */
-static COLD_ATTRIBUTE void update_common(struct htable *ht, const void *p)
+static COLD void update_common(struct htable *ht, const void *p)
 {
        unsigned int i;
        uintptr_t maskdiff, bitsdiff;
@@ -206,6 +226,7 @@ static COLD_ATTRIBUTE void update_common(struct htable *ht, const void *p)
        if (ht->elems == 0) {
                ht->common_mask = -1;
                ht->common_bits = (uintptr_t)p;
+               ht->perfect_bit = 1;
                return;
        }
 
@@ -224,9 +245,10 @@ static COLD_ATTRIBUTE void update_common(struct htable *ht, const void *p)
                ht->table[i] |= bitsdiff;
        }
 
-       /* Take away those bits from our mask and set. */
+       /* Take away those bits from our mask, bits and perfect bit. */
        ht->common_mask &= ~maskdiff;
        ht->common_bits &= ~maskdiff;
+       ht->perfect_bit &= ~maskdiff;
 }
 
 bool htable_add(struct htable *ht, size_t hash, const void *p)