diff options
Diffstat (limited to 'src/vppinfra/bihash_template.c')
-rw-r--r-- | src/vppinfra/bihash_template.c | 624 |
1 files changed, 624 insertions, 0 deletions
diff --git a/src/vppinfra/bihash_template.c b/src/vppinfra/bihash_template.c new file mode 100644 index 00000000..56c410b5 --- /dev/null +++ b/src/vppinfra/bihash_template.c @@ -0,0 +1,624 @@ +/* + * Copyright (c) 2015 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/** @cond DOCUMENTATION_IS_IN_BIHASH_DOC_H */ + +void BV (clib_bihash_init) + (BVT (clib_bihash) * h, char *name, u32 nbuckets, uword memory_size) +{ + void *oldheap; + int i; + + nbuckets = 1 << (max_log2 (nbuckets)); + + h->name = (u8 *) name; + h->nbuckets = nbuckets; + h->log2_nbuckets = max_log2 (nbuckets); + h->cache_hits = 0; + h->cache_misses = 0; + + h->mheap = mheap_alloc (0 /* use VM */ , memory_size); + + oldheap = clib_mem_set_heap (h->mheap); + vec_validate_aligned (h->buckets, nbuckets - 1, CLIB_CACHE_LINE_BYTES); + h->writer_lock = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, + CLIB_CACHE_LINE_BYTES); + h->writer_lock[0] = 0; + + for (i = 0; i < nbuckets; i++) + BV (clib_bihash_reset_cache) (h->buckets + i); + + clib_mem_set_heap (oldheap); +} + +void BV (clib_bihash_free) (BVT (clib_bihash) * h) +{ + mheap_free (h->mheap); + memset (h, 0, sizeof (*h)); +} + +static +BVT (clib_bihash_value) * +BV (value_alloc) (BVT (clib_bihash) * h, u32 log2_pages) +{ + BVT (clib_bihash_value) * rv = 0; + void *oldheap; + + ASSERT (h->writer_lock[0]); + if (log2_pages >= vec_len (h->freelists) || h->freelists[log2_pages] == 0) + { + oldheap = clib_mem_set_heap (h->mheap); + + vec_validate (h->freelists, log2_pages); + rv = clib_mem_alloc_aligned ((sizeof (*rv) * (1 << log2_pages)), + CLIB_CACHE_LINE_BYTES); + clib_mem_set_heap (oldheap); + goto initialize; + } + rv = h->freelists[log2_pages]; + h->freelists[log2_pages] = rv->next_free; + +initialize: + ASSERT (rv); + /* + * Latest gcc complains that the length arg is zero + * if we replace (1<<log2_pages) with vec_len(rv). + * No clue. + */ + memset (rv, 0xff, sizeof (*rv) * (1 << log2_pages)); + return rv; +} + +static void +BV (value_free) (BVT (clib_bihash) * h, BVT (clib_bihash_value) * v, + u32 log2_pages) +{ + ASSERT (h->writer_lock[0]); + + ASSERT (vec_len (h->freelists) > log2_pages); + + v->next_free = h->freelists[log2_pages]; + h->freelists[log2_pages] = v; +} + +static inline void +BV (make_working_copy) (BVT (clib_bihash) * h, BVT (clib_bihash_bucket) * b) +{ + BVT (clib_bihash_value) * v; + BVT (clib_bihash_bucket) working_bucket __attribute__ ((aligned (8))); + void *oldheap; + BVT (clib_bihash_value) * working_copy; + u32 thread_index = os_get_thread_index (); + int log2_working_copy_length; + + if (thread_index >= vec_len (h->working_copies)) + { + oldheap = clib_mem_set_heap (h->mheap); + vec_validate (h->working_copies, thread_index); + vec_validate_init_empty (h->working_copy_lengths, thread_index, ~0); + clib_mem_set_heap (oldheap); + } + + /* + * working_copies are per-cpu so that near-simultaneous + * updates from multiple threads will not result in sporadic, spurious + * lookup failures. + */ + working_copy = h->working_copies[thread_index]; + log2_working_copy_length = h->working_copy_lengths[thread_index]; + + h->saved_bucket.as_u64 = b->as_u64; + oldheap = clib_mem_set_heap (h->mheap); + + if (b->log2_pages > log2_working_copy_length) + { + if (working_copy) + clib_mem_free (working_copy); + + working_copy = clib_mem_alloc_aligned + (sizeof (working_copy[0]) * (1 << b->log2_pages), + CLIB_CACHE_LINE_BYTES); + h->working_copy_lengths[thread_index] = b->log2_pages; + h->working_copies[thread_index] = working_copy; + } + + clib_mem_set_heap (oldheap); + + /* Lock the bucket... */ + while (BV (clib_bihash_lock_bucket) (b) == 0) + ; + + v = BV (clib_bihash_get_value) (h, b->offset); + + clib_memcpy (working_copy, v, sizeof (*v) * (1 << b->log2_pages)); + working_bucket.as_u64 = b->as_u64; + working_bucket.offset = BV (clib_bihash_get_offset) (h, working_copy); + CLIB_MEMORY_BARRIER (); + b->as_u64 = working_bucket.as_u64; + h->working_copies[thread_index] = working_copy; +} + +static +BVT (clib_bihash_value) * +BV (split_and_rehash) + (BVT (clib_bihash) * h, + BVT (clib_bihash_value) * old_values, u32 old_log2_pages, + u32 new_log2_pages) +{ + BVT (clib_bihash_value) * new_values, *new_v; + int i, j, length_in_kvs; + + new_values = BV (value_alloc) (h, new_log2_pages); + length_in_kvs = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE; + + for (i = 0; i < length_in_kvs; i++) + { + u64 new_hash; + + /* Entry not in use? Forget it */ + if (BV (clib_bihash_is_free) (&(old_values->kvp[i]))) + continue; + + /* rehash the item onto its new home-page */ + new_hash = BV (clib_bihash_hash) (&(old_values->kvp[i])); + new_hash >>= h->log2_nbuckets; + new_hash &= (1 << new_log2_pages) - 1; + new_v = &new_values[new_hash]; + + /* Across the new home-page */ + for (j = 0; j < BIHASH_KVP_PER_PAGE; j++) + { + /* Empty slot */ + if (BV (clib_bihash_is_free) (&(new_v->kvp[j]))) + { + clib_memcpy (&(new_v->kvp[j]), &(old_values->kvp[i]), + sizeof (new_v->kvp[j])); + goto doublebreak; + } + } + /* Crap. Tell caller to try again */ + BV (value_free) (h, new_values, new_log2_pages); + return 0; + doublebreak:; + } + + return new_values; +} + +static +BVT (clib_bihash_value) * +BV (split_and_rehash_linear) + (BVT (clib_bihash) * h, + BVT (clib_bihash_value) * old_values, u32 old_log2_pages, + u32 new_log2_pages) +{ + BVT (clib_bihash_value) * new_values; + int i, j, new_length, old_length; + + new_values = BV (value_alloc) (h, new_log2_pages); + new_length = (1 << new_log2_pages) * BIHASH_KVP_PER_PAGE; + old_length = (1 << old_log2_pages) * BIHASH_KVP_PER_PAGE; + + j = 0; + /* Across the old value array */ + for (i = 0; i < old_length; i++) + { + /* Find a free slot in the new linear scan bucket */ + for (; j < new_length; j++) + { + /* Old value not in use? Forget it. */ + if (BV (clib_bihash_is_free) (&(old_values->kvp[i]))) + goto doublebreak; + + /* New value should never be in use */ + if (BV (clib_bihash_is_free) (&(new_values->kvp[j]))) + { + /* Copy the old value and move along */ + clib_memcpy (&(new_values->kvp[j]), &(old_values->kvp[i]), + sizeof (new_values->kvp[j])); + j++; + goto doublebreak; + } + } + /* This should never happen... */ + clib_warning ("BUG: linear rehash failed!"); + BV (value_free) (h, new_values, new_log2_pages); + return 0; + + doublebreak:; + } + return new_values; +} + +int BV (clib_bihash_add_del) + (BVT (clib_bihash) * h, BVT (clib_bihash_kv) * add_v, int is_add) +{ + u32 bucket_index; + BVT (clib_bihash_bucket) * b, tmp_b; + BVT (clib_bihash_value) * v, *new_v, *save_new_v, *working_copy; + int rv = 0; + int i, limit; + u64 hash, new_hash; + u32 new_log2_pages, old_log2_pages; + u32 thread_index = os_get_thread_index (); + int mark_bucket_linear; + int resplit_once; + + hash = BV (clib_bihash_hash) (add_v); + + bucket_index = hash & (h->nbuckets - 1); + b = &h->buckets[bucket_index]; + + hash >>= h->log2_nbuckets; + + tmp_b.linear_search = 0; + + while (__sync_lock_test_and_set (h->writer_lock, 1)) + ; + + /* First elt in the bucket? */ + if (b->offset == 0) + { + if (is_add == 0) + { + rv = -1; + goto unlock; + } + + v = BV (value_alloc) (h, 0); + + *v->kvp = *add_v; + tmp_b.as_u64 = 0; + tmp_b.offset = BV (clib_bihash_get_offset) (h, v); + + b->as_u64 = tmp_b.as_u64; + goto unlock; + } + + /* Note: this leaves the cache disabled */ + BV (make_working_copy) (h, b); + + v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset); + + limit = BIHASH_KVP_PER_PAGE; + v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0; + if (b->linear_search) + limit <<= b->log2_pages; + + if (is_add) + { + /* + * For obvious (in hindsight) reasons, see if we're supposed to + * replace an existing key, then look for an empty slot. + */ + for (i = 0; i < limit; i++) + { + if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key))) + { + clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v)); + CLIB_MEMORY_BARRIER (); + /* Restore the previous (k,v) pairs */ + b->as_u64 = h->saved_bucket.as_u64; + goto unlock; + } + } + for (i = 0; i < limit; i++) + { + if (BV (clib_bihash_is_free) (&(v->kvp[i]))) + { + clib_memcpy (&(v->kvp[i]), add_v, sizeof (*add_v)); + CLIB_MEMORY_BARRIER (); + b->as_u64 = h->saved_bucket.as_u64; + goto unlock; + } + } + /* no room at the inn... split case... */ + } + else + { + for (i = 0; i < limit; i++) + { + if (!memcmp (&(v->kvp[i]), &add_v->key, sizeof (add_v->key))) + { + memset (&(v->kvp[i]), 0xff, sizeof (*(add_v))); + CLIB_MEMORY_BARRIER (); + b->as_u64 = h->saved_bucket.as_u64; + goto unlock; + } + } + rv = -3; + b->as_u64 = h->saved_bucket.as_u64; + goto unlock; + } + + old_log2_pages = h->saved_bucket.log2_pages; + new_log2_pages = old_log2_pages + 1; + mark_bucket_linear = 0; + + working_copy = h->working_copies[thread_index]; + resplit_once = 0; + + new_v = BV (split_and_rehash) (h, working_copy, old_log2_pages, + new_log2_pages); + if (new_v == 0) + { + try_resplit: + resplit_once = 1; + new_log2_pages++; + /* Try re-splitting. If that fails, fall back to linear search */ + new_v = BV (split_and_rehash) (h, working_copy, old_log2_pages, + new_log2_pages); + if (new_v == 0) + { + mark_linear: + new_log2_pages--; + /* pinned collisions, use linear search */ + new_v = + BV (split_and_rehash_linear) (h, working_copy, old_log2_pages, + new_log2_pages); + mark_bucket_linear = 1; + } + } + + /* Try to add the new entry */ + save_new_v = new_v; + new_hash = BV (clib_bihash_hash) (add_v); + limit = BIHASH_KVP_PER_PAGE; + if (mark_bucket_linear) + limit <<= new_log2_pages; + new_hash >>= h->log2_nbuckets; + new_hash &= (1 << new_log2_pages) - 1; + new_v += mark_bucket_linear ? 0 : new_hash; + + for (i = 0; i < limit; i++) + { + if (BV (clib_bihash_is_free) (&(new_v->kvp[i]))) + { + clib_memcpy (&(new_v->kvp[i]), add_v, sizeof (*add_v)); + goto expand_ok; + } + } + + /* Crap. Try again */ + BV (value_free) (h, save_new_v, new_log2_pages); + /* + * If we've already doubled the size of the bucket once, + * fall back to linear search now. + */ + if (resplit_once) + goto mark_linear; + else + goto try_resplit; + +expand_ok: + /* Keep track of the number of linear-scan buckets */ + if (tmp_b.linear_search ^ mark_bucket_linear) + h->linear_buckets += (mark_bucket_linear == 1) ? 1 : -1; + + tmp_b.log2_pages = new_log2_pages; + tmp_b.offset = BV (clib_bihash_get_offset) (h, save_new_v); + tmp_b.linear_search = mark_bucket_linear; + + CLIB_MEMORY_BARRIER (); + b->as_u64 = tmp_b.as_u64; + v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset); + BV (value_free) (h, v, old_log2_pages); + +unlock: + BV (clib_bihash_reset_cache) (b); + BV (clib_bihash_unlock_bucket) (b); + CLIB_MEMORY_BARRIER (); + h->writer_lock[0] = 0; + return rv; +} + +int BV (clib_bihash_search) + (BVT (clib_bihash) * h, + BVT (clib_bihash_kv) * search_key, BVT (clib_bihash_kv) * valuep) +{ + u64 hash; + u32 bucket_index; + BVT (clib_bihash_value) * v; +#if BIHASH_KVP_CACHE_SIZE > 0 + BVT (clib_bihash_kv) * kvp; +#endif + BVT (clib_bihash_bucket) * b; + int i, limit; + + ASSERT (valuep); + + hash = BV (clib_bihash_hash) (search_key); + + bucket_index = hash & (h->nbuckets - 1); + b = &h->buckets[bucket_index]; + + if (b->offset == 0) + return -1; + +#if BIHASH_KVP_CACHE_SIZE > 0 + /* Check the cache, if currently enabled */ + if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0)) + { + limit = BIHASH_KVP_CACHE_SIZE; + kvp = b->cache; + for (i = 0; i < limit; i++) + { + if (BV (clib_bihash_key_compare) (kvp[i].key, search_key->key)) + { + *valuep = kvp[i]; + h->cache_hits++; + return 0; + } + } + } +#endif + + hash >>= h->log2_nbuckets; + + v = BV (clib_bihash_get_value) (h, b->offset); + limit = BIHASH_KVP_PER_PAGE; + v += (b->linear_search == 0) ? hash & ((1 << b->log2_pages) - 1) : 0; + if (PREDICT_FALSE (b->linear_search)) + limit <<= b->log2_pages; + + for (i = 0; i < limit; i++) + { + if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key)) + { + *valuep = v->kvp[i]; + +#if BIHASH_KVP_CACHE_SIZE > 0 + u8 cache_slot; + /* Shut off the cache */ + if (BV (clib_bihash_lock_bucket) (b)) + { + cache_slot = BV (clib_bihash_get_lru) (b); + b->cache[cache_slot] = v->kvp[i]; + BV (clib_bihash_update_lru) (b, cache_slot); + + /* Reenable the cache */ + BV (clib_bihash_unlock_bucket) (b); + h->cache_misses++; + } +#endif + return 0; + } + } + return -1; +} + +u8 *BV (format_bihash_lru) (u8 * s, va_list * args) +{ +#if BIHASH_KVP_SIZE > 0 + int i; + BVT (clib_bihash_bucket) * b = va_arg (*args, BVT (clib_bihash_bucket) *); + u16 cache_lru = b->cache_lru; + + s = format (s, "cache %s, order ", cache_lru & (1 << 15) ? "on" : "off"); + + for (i = 0; i < BIHASH_KVP_CACHE_SIZE; i++) + s = format (s, "[%d] ", ((cache_lru >> (3 * i)) & 7)); + + return (s); +#else + return format (s, "cache not configured"); +#endif +} + +void +BV (clib_bihash_update_lru_not_inline) (BVT (clib_bihash_bucket) * b, u8 slot) +{ +#if BIHASH_KVP_SIZE > 0 + BV (clib_bihash_update_lru) (b, slot); +#endif +} + +u8 *BV (format_bihash) (u8 * s, va_list * args) +{ + BVT (clib_bihash) * h = va_arg (*args, BVT (clib_bihash) *); + int verbose = va_arg (*args, int); + BVT (clib_bihash_bucket) * b; + BVT (clib_bihash_value) * v; + int i, j, k; + u64 active_elements = 0; + + s = format (s, "Hash table %s\n", h->name ? h->name : (u8 *) "(unnamed)"); + + for (i = 0; i < h->nbuckets; i++) + { + b = &h->buckets[i]; + if (b->offset == 0) + { + if (verbose > 1) + s = format (s, "[%d]: empty\n", i); + continue; + } + + if (verbose) + { + s = format (s, "[%d]: heap offset %d, len %d, linear %d\n", i, + b->offset, (1 << b->log2_pages), b->linear_search); + } + + v = BV (clib_bihash_get_value) (h, b->offset); + for (j = 0; j < (1 << b->log2_pages); j++) + { + for (k = 0; k < BIHASH_KVP_PER_PAGE; k++) + { + if (BV (clib_bihash_is_free) (&v->kvp[k])) + { + if (verbose > 1) + s = format (s, " %d: empty\n", + j * BIHASH_KVP_PER_PAGE + k); + continue; + } + if (verbose) + { + s = format (s, " %d: %U\n", + j * BIHASH_KVP_PER_PAGE + k, + BV (format_bihash_kvp), &(v->kvp[k])); + } + active_elements++; + } + v++; + } + } + + s = format (s, " %lld active elements\n", active_elements); + s = format (s, " %d free lists\n", vec_len (h->freelists)); + s = format (s, " %d linear search buckets\n", h->linear_buckets); + s = format (s, " %lld cache hits, %lld cache misses\n", + h->cache_hits, h->cache_misses); + return s; +} + +void BV (clib_bihash_foreach_key_value_pair) + (BVT (clib_bihash) * h, void *callback, void *arg) +{ + int i, j, k; + BVT (clib_bihash_bucket) * b; + BVT (clib_bihash_value) * v; + void (*fp) (BVT (clib_bihash_kv) *, void *) = callback; + + for (i = 0; i < h->nbuckets; i++) + { + b = &h->buckets[i]; + if (b->offset == 0) + continue; + + v = BV (clib_bihash_get_value) (h, b->offset); + for (j = 0; j < (1 << b->log2_pages); j++) + { + for (k = 0; k < BIHASH_KVP_PER_PAGE; k++) + { + if (BV (clib_bihash_is_free) (&v->kvp[k])) + continue; + + (*fp) (&v->kvp[k], arg); + } + v++; + } + } +} + +/** @endcond */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ |