--- /dev/null
+/*
+ Copyright (c) 2017 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.
+*/
+
+/*
+ * cuckoo hash implementation based on paper
+ * 'Algorithmic Improvements for Fast Concurrent Cuckoo Hashing'
+ * by Xiaozhou Li, David G. Andersen, Michael Kaminsky, Michael J. Freedman
+ * and their libcuckoo implementation (https://github.com/efficient/libcuckoo)
+ */
+
+/*
+ * Note: to instantiate the template multiple times in a single file,
+ * #undef __included_cuckoo_template_h__...
+ */
+#ifndef __included_cuckoo_template_h__
+#define __included_cuckoo_template_h__
+
+#include <vppinfra/heap.h>
+#include <vppinfra/format.h>
+#include <vppinfra/pool.h>
+#include <vppinfra/lock.h>
+#include <vppinfra/error.h>
+#include <vppinfra/hash.h>
+#include <vppinfra/cache.h>
+
+#ifndef CLIB_CUCKOO_TYPE
+#error CLIB_CUCKOO_TYPE not defined
+#endif
+
+#ifndef CLIB_CUCKOO_BFS_MAX_STEPS
+#error CLIB_CUCKOO_BFS_MAX_STEPS not defined
+#endif
+
+#ifndef CLIB_CUCKOO_KVP_PER_BUCKET
+#error CLIB_CUCKOO_KVP_PER_BUCKET not defined
+#endif
+
+#ifndef CLIB_CUCKOO_LOG2_KVP_PER_BUCKET
+#error CLIB_CUCKOO_LOG2_KVP_PER_BUCKET not defined
+#endif
+
+#ifndef CLIB_CUCKOO_BFS_MAX_PATH_LENGTH
+#error CLIB_CUCKOO_BFS_MAX_PATH_LENGTH not defined
+#endif
+
+STATIC_ASSERT (CLIB_CUCKOO_KVP_PER_BUCKET ==
+ (1 << CLIB_CUCKOO_LOG2_KVP_PER_BUCKET),
+ "CLIB_CUCKOO_KVP_PER_BUCKET != (1 << CLIB_CUCKOO_LOG2_KVP_PER_BUCKET");
+
+#define _cv(a, b) a##b
+#define __cv(a, b) _cv (a, b)
+#define CV(a) __cv (a, CLIB_CUCKOO_TYPE)
+
+#define _cvt(a, b) a##b##_t
+#define __cvt(a, b) _cvt (a, b)
+#define CVT(a) __cvt (a, CLIB_CUCKOO_TYPE)
+
+typedef u64 clib_cuckoo_bucket_aux_t;
+
+#define CLIB_CUCKOO_USE_COUNT_BIT_WIDTH (1 + CLIB_CUCKOO_LOG2_KVP_PER_BUCKET)
+
+always_inline u64
+clib_cuckoo_bucket_aux_get_version (clib_cuckoo_bucket_aux_t aux)
+{
+ return aux >> (1 + CLIB_CUCKOO_USE_COUNT_BIT_WIDTH);
+}
+
+always_inline int
+clib_cuckoo_bucket_aux_get_use_count (clib_cuckoo_bucket_aux_t aux)
+{
+ u64 use_count_mask = (1 << CLIB_CUCKOO_USE_COUNT_BIT_WIDTH) - 1;
+ return (aux >> 1) & use_count_mask;
+}
+
+always_inline int
+clib_cuckoo_bucket_aux_get_writer_flag (clib_cuckoo_bucket_aux_t aux)
+{
+ return aux & 1;
+}
+
+always_inline clib_cuckoo_bucket_aux_t
+clib_cuckoo_bucket_aux_pack (u64 version, int use_count, int writer_flag)
+{
+ return (version << (1 + CLIB_CUCKOO_USE_COUNT_BIT_WIDTH)) +
+ (use_count << 1) + writer_flag;
+}
+
+always_inline clib_cuckoo_bucket_aux_t
+clib_cuckoo_bucket_aux_set_version (clib_cuckoo_bucket_aux_t aux, u64 version)
+{
+ int use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
+ int writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (aux);
+ return clib_cuckoo_bucket_aux_pack (version, use_count, writer_flag);
+}
+
+always_inline clib_cuckoo_bucket_aux_t
+clib_cuckoo_bucket_aux_set_use_count (clib_cuckoo_bucket_aux_t aux,
+ int use_count)
+{
+ u64 version = clib_cuckoo_bucket_aux_get_version (aux);
+ int writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (aux);
+ return clib_cuckoo_bucket_aux_pack (version, use_count, writer_flag);
+}
+
+always_inline clib_cuckoo_bucket_aux_t
+clib_cuckoo_bucket_aux_set_writer_flag (clib_cuckoo_bucket_aux_t aux,
+ int writer_flag)
+{
+ u64 version = clib_cuckoo_bucket_aux_get_version (aux);
+ int use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
+ return clib_cuckoo_bucket_aux_pack (version, use_count, writer_flag);
+}
+
+#define PATH_BITS_REQ \
+ (CLIB_CUCKOO_BFS_MAX_PATH_LENGTH * CLIB_CUCKOO_LOG2_KVP_PER_BUCKET)
+
+#if PATH_BITS_REQ <= 8
+typedef u8 path_data_t;
+#elif PATH_BITS_REQ <= 16
+typedef u16 path_data_t;
+#elif PATH_BITS_REQ <= 32
+typedef u32 path_data_t;
+#elif PATH_BITS_REQ <= 64
+typedef u64 path_data_t;
+#else
+#error no suitable datatype for path storage...
+#endif
+
+typedef struct
+{
+ /** bucket where this path begins */
+ u64 start;
+ /** bucket at end of path */
+ u64 bucket;
+ /** length of the path */
+ u8 length;
+ /** holds compressed offsets in buckets along path */
+ path_data_t data;
+} clib_cuckoo_path_t;
+
+typedef struct
+{
+ CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
+
+ /** reduced hashes corresponding to elements */
+ u8 reduced_hashes[CLIB_CUCKOO_KVP_PER_BUCKET];
+
+ /** auxiliary data - version, writer flag and used count */
+ volatile clib_cuckoo_bucket_aux_t aux;
+
+ /** cuckoo elements in this bucket */
+ CVT (clib_cuckoo_kv) elts[CLIB_CUCKOO_KVP_PER_BUCKET];
+} CVT (clib_cuckoo_bucket);
+
+#define clib_cuckoo_bucket_foreach_idx(var) \
+ for (var = 0; var < CLIB_CUCKOO_KVP_PER_BUCKET; var++)
+
+#if CLIB_CUCKOO_OPTIMIZE_UNROLL
+#if CLIB_CUCKOO_KVP_PER_BUCKET == 2
+#define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
+ do \
+ { \
+ var = 0; \
+ body; \
+ var = 1; \
+ body; \
+ } \
+ while (0);
+#elif CLIB_CUCKOO_KVP_PER_BUCKET == 4
+#define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
+ do \
+ { \
+ var = 0; \
+ body; \
+ var = 1; \
+ body; \
+ var = 2; \
+ body; \
+ var = 3; \
+ body; \
+ } \
+ while (0);
+#elif CLIB_CUCKOO_KVP_PER_BUCKET == 8
+#define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
+ do \
+ { \
+ var = 0; \
+ body; \
+ var = 1; \
+ body; \
+ var = 2; \
+ body; \
+ var = 3; \
+ body; \
+ var = 4; \
+ body; \
+ var = 5; \
+ body; \
+ var = 6; \
+ body; \
+ var = 7; \
+ body; \
+ } \
+ while (0);
+#else
+#define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
+ clib_cuckoo_bucket_foreach_idx (var) \
+ { \
+ body; \
+ }
+#endif
+#else /* CLIB_CUCKOO_OPTIMIZE_UNROLL */
+#define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
+ clib_cuckoo_bucket_foreach_idx (var) \
+ { \
+ body; \
+ }
+#endif /* CLIB_CUCKOO_OPTIMIZE_UNROLL */
+
+#define clib_cuckoo_bucket_foreach_elt_index(var, bucket) \
+ for (var = 0; var < CLIB_CUCKOO_KVP_PER_BUCKET; ++i)
+
+#define clib_cuckoo_foreach_bucket(var, h, body) \
+ do \
+ { \
+ CVT (clib_cuckoo_bucket) *__buckets = h->buckets; \
+ vec_foreach (var, __buckets) \
+ { \
+ body; \
+ } \
+ } \
+ while (0)
+
+typedef struct CV (clib_cuckoo)
+{
+ /** vector of elements containing key-value pairs and auxiliary data */
+ CVT (clib_cuckoo_bucket) * volatile buckets;
+
+ /** garbage to be freed once its safe to do so .. */
+ CVT (clib_cuckoo_bucket) * *to_be_freed;
+
+ /** hash table name */
+ const char *name;
+
+ /** pool of cuckoo paths (reused when doing bfd search) */
+ clib_cuckoo_path_t *paths;
+
+ /**
+ * vector used as queue when doing cuckoo path searches - holds offsets
+ * in paths pool
+ */
+ uword *bfs_search_queue;
+
+ /**
+ * writer lock - whether this lock is taken or not has zero effect on
+ * readers
+ */
+ clib_spinlock_t writer_lock;
+
+ /** caller context passed to callback with garbage notification */
+ void *garbage_ctx;
+
+ /**
+ * garbage notify function - called when some garbage needs to be collected
+ * in main thread while other threads are stopped
+ */
+ void (*garbage_callback) (struct CV (clib_cuckoo) * h, void *garbage_ctx);
+
+#if CLIB_CUCKOO_DEBUG_COUNTERS
+ u64 steps_exceeded;
+ u64 bfs_queue_emptied;
+ u64 fast_adds;
+ u64 slow_adds;
+ u64 rehashes;
+#endif
+
+} CVT (clib_cuckoo);
+
+void CV (clib_cuckoo_init) (CVT (clib_cuckoo) * h, const char *name,
+ uword nbuckets,
+ void (*garbage_callback) (CVT (clib_cuckoo) *,
+ void *),
+ void *garbage_ctx);
+
+void CV (clib_cuckoo_garbage_collect) (CVT (clib_cuckoo) * h);
+
+void CV (clib_cuckoo_free) (CVT (clib_cuckoo) * h);
+
+int CV (clib_cuckoo_add_del) (CVT (clib_cuckoo) * h,
+ CVT (clib_cuckoo_kv) * add_v, int is_add,
+ int dont_overwrite);
+int CV (clib_cuckoo_search) (CVT (clib_cuckoo) * h,
+ CVT (clib_cuckoo_kv) * search_v,
+ CVT (clib_cuckoo_kv) * return_v);
+
+void CV (clib_cuckoo_foreach_key_value_pair) (CVT (clib_cuckoo) * h,
+ void *callback, void *arg);
+
+float CV (clib_cuckoo_calc_load) (CVT (clib_cuckoo) * h);
+
+format_function_t CV (format_cuckoo);
+format_function_t CV (format_cuckoo_kvp);
+
+always_inline u8
+clib_cuckoo_reduce_hash (u64 hash)
+{
+ u32 v32 = ((u32) hash) ^ ((u32) (hash >> 32));
+ u16 v16 = ((u16) v32) ^ ((u16) (v32 >> 16));
+ u8 v8 = ((u8) v16) ^ ((u8) (v16 >> 8));
+ return v8;
+}
+
+always_inline u64
+clib_cuckoo_get_other_bucket (u64 nbuckets, u64 bucket, u8 reduced_hash)
+{
+ u64 mask = (nbuckets - 1);
+ return (bucket ^ ((reduced_hash + 1) * 0xc6a4a7935bd1e995)) & mask;
+}
+
+always_inline clib_cuckoo_lookup_info_t
+CV (clib_cuckoo_calc_lookup) (CVT (clib_cuckoo_bucket) * buckets, u64 hash)
+{
+ clib_cuckoo_lookup_info_t lookup;
+ u64 nbuckets = vec_len (buckets);
+ u64 mask = (nbuckets - 1);
+ lookup.bucket1 = hash & mask;
+#if CLIB_CUCKOO_OPTIMIZE_PREFETCH
+ CLIB_PREFETCH (vec_elt_at_index (buckets, lookup.bucket1),
+ sizeof (*buckets), LOAD);
+#endif
+ u8 reduced_hash = clib_cuckoo_reduce_hash (hash);
+ lookup.bucket2 =
+ clib_cuckoo_get_other_bucket (nbuckets, lookup.bucket1, reduced_hash);
+#if CLIB_CUCKOO_OPTIMIZE_PREFETCH
+ CLIB_PREFETCH (vec_elt_at_index (buckets, lookup.bucket2),
+ sizeof (*buckets), LOAD);
+#endif
+ lookup.reduced_hash = reduced_hash;
+ ASSERT (lookup.bucket1 < nbuckets);
+ ASSERT (lookup.bucket2 < nbuckets);
+ return lookup;
+}
+
+/**
+ * search for key within bucket
+ */
+always_inline int CV (clib_cuckoo_bucket_search) (CVT (clib_cuckoo_bucket) *
+ b,
+ CVT (clib_cuckoo_kv) * kvp,
+ u8 reduced_hash)
+{
+ clib_cuckoo_bucket_aux_t bucket_aux;
+ u8 writer_flag;
+ do
+ {
+ bucket_aux = b->aux;
+ writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (bucket_aux);
+ }
+ while (PREDICT_FALSE (writer_flag)); /* loop while writer flag is set */
+
+ int i;
+#if CLIB_CUCKOO_OPTIMIZE_USE_COUNT_LIMITS_SEARCH
+ const int use_count = clib_cuckoo_bucket_aux_get_use_count (bucket_aux);
+#endif
+ /* *INDENT-OFF* */
+ clib_cuckoo_bucket_foreach_idx_unrolled (i, {
+#if CLIB_CUCKOO_OPTIMIZE_USE_COUNT_LIMITS_SEARCH
+ if (i > use_count)
+ {
+ break;
+ }
+#endif
+ if (CV (clib_cuckoo_key_compare) (kvp->key, b->elts[i].key))
+ {
+ kvp->value = b->elts[i].value;
+ clib_cuckoo_bucket_aux_t bucket_aux2 = b->aux;
+ if (PREDICT_TRUE (clib_cuckoo_bucket_aux_get_version (bucket_aux) ==
+ clib_cuckoo_bucket_aux_get_version (bucket_aux2)))
+ {
+ /* yay, fresh data */
+ return CLIB_CUCKOO_ERROR_SUCCESS;
+ }
+ else
+ {
+ /* oops, modification detected */
+ return CLIB_CUCKOO_ERROR_AGAIN;
+ }
+ }
+ });
+ /* *INDENT-ON* */
+ return CLIB_CUCKOO_ERROR_NOT_FOUND;
+}
+
+always_inline int
+CV (clib_cuckoo_search_inline_with_hash) (CVT (clib_cuckoo) * h, u64 hash,
+ CVT (clib_cuckoo_kv) * kvp)
+{
+ CVT (clib_cuckoo_bucket) * buckets = h->buckets;
+ uword bucket1, bucket2;
+ u8 reduced_hash;
+ u64 nbuckets = vec_len (buckets);
+ u64 mask = nbuckets - 1;
+ int rv;
+
+ bucket1 = hash & mask;
+ reduced_hash = clib_cuckoo_reduce_hash (hash);
+
+again:
+ rv = CV (clib_cuckoo_bucket_search) (vec_elt_at_index (buckets, bucket1),
+ kvp, reduced_hash);
+
+ if (rv == CLIB_CUCKOO_ERROR_SUCCESS)
+ return CLIB_CUCKOO_ERROR_SUCCESS;
+
+ if (PREDICT_FALSE (rv == CLIB_CUCKOO_ERROR_AGAIN))
+ goto again;
+
+ bucket2 = clib_cuckoo_get_other_bucket (nbuckets, bucket1, reduced_hash);
+ rv = CV (clib_cuckoo_bucket_search) (vec_elt_at_index (buckets, bucket2),
+ kvp, reduced_hash);
+
+ /* change to 2nd bucket could bump the item to 1st bucket and the bucket
+ * indexes might not even be valid anymore - restart the search */
+ if (PREDICT_FALSE (rv == CLIB_CUCKOO_ERROR_AGAIN))
+ goto again;
+
+ return rv;
+}
+
+always_inline int CV (clib_cuckoo_search_inline) (CVT (clib_cuckoo) * h,
+ CVT (clib_cuckoo_kv) * kvp)
+{
+ u64 hash = CV (clib_cuckoo_hash) (kvp);
+ return CV (clib_cuckoo_search_inline_with_hash) (h, hash, kvp);
+}
+
+#endif /* __included_cuckoo_template_h__ */
+
+/** @endcond */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
Code Review / vpp.git / blobdiff