FD.io VPP  v19.01.3-6-g70449b9b9
Vector Packet Processing
cuckoo_template.h
Go to the documentation of this file.
1 /*
2  Copyright (c) 2017 Cisco and/or its affiliates.
3 
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at:
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15 */
16 
17 /*
18  * cuckoo hash implementation based on paper
19  * 'Algorithmic Improvements for Fast Concurrent Cuckoo Hashing'
20  * by Xiaozhou Li, David G. Andersen, Michael Kaminsky, Michael J. Freedman
21  * and their libcuckoo implementation (https://github.com/efficient/libcuckoo)
22  */
23 
24 /*
25  * Note: to instantiate the template multiple times in a single file,
26  * #undef __included_cuckoo_template_h__...
27  */
28 #ifndef __included_cuckoo_template_h__
29 #define __included_cuckoo_template_h__
30 
31 #include <vppinfra/heap.h>
32 #include <vppinfra/format.h>
33 #include <vppinfra/pool.h>
34 #include <vppinfra/lock.h>
35 #include <vppinfra/error.h>
36 #include <vppinfra/hash.h>
37 #include <vppinfra/cache.h>
38 #include <vppinfra/cuckoo_8_8.h>
39 
40 #ifndef CLIB_CUCKOO_TYPE
41 #error CLIB_CUCKOO_TYPE not defined
42 #endif
43 
44 #ifndef CLIB_CUCKOO_BFS_MAX_STEPS
45 #error CLIB_CUCKOO_BFS_MAX_STEPS not defined
46 #endif
47 
48 #ifndef CLIB_CUCKOO_KVP_PER_BUCKET
49 #error CLIB_CUCKOO_KVP_PER_BUCKET not defined
50 #endif
51 
52 #ifndef CLIB_CUCKOO_LOG2_KVP_PER_BUCKET
53 #error CLIB_CUCKOO_LOG2_KVP_PER_BUCKET not defined
54 #endif
55 
56 #ifndef CLIB_CUCKOO_BFS_MAX_PATH_LENGTH
57 #error CLIB_CUCKOO_BFS_MAX_PATH_LENGTH not defined
58 #endif
59 
62  "CLIB_CUCKOO_KVP_PER_BUCKET != (1 << CLIB_CUCKOO_LOG2_KVP_PER_BUCKET");
63 
64 #define _cv(a, b) a##b
65 #define __cv(a, b) _cv (a, b)
66 #define CV(a) __cv (a, CLIB_CUCKOO_TYPE)
67 
68 #define _cvt(a, b) a##b##_t
69 #define __cvt(a, b) _cvt (a, b)
70 #define CVT(a) __cvt (a, CLIB_CUCKOO_TYPE)
71 
73 
74 #define CLIB_CUCKOO_USE_COUNT_BIT_WIDTH (1 + CLIB_CUCKOO_LOG2_KVP_PER_BUCKET)
75 
77 clib_cuckoo_bucket_aux_get_version (clib_cuckoo_bucket_aux_t aux)
78 {
79  return aux >> (1 + CLIB_CUCKOO_USE_COUNT_BIT_WIDTH);
80 }
81 
82 always_inline int
83 clib_cuckoo_bucket_aux_get_use_count (clib_cuckoo_bucket_aux_t aux)
84 {
85  u64 use_count_mask = (1 << CLIB_CUCKOO_USE_COUNT_BIT_WIDTH) - 1;
86  return (aux >> 1) & use_count_mask;
87 }
88 
89 always_inline int
90 clib_cuckoo_bucket_aux_get_writer_flag (clib_cuckoo_bucket_aux_t aux)
91 {
92  return aux & 1;
93 }
94 
95 always_inline clib_cuckoo_bucket_aux_t
96 clib_cuckoo_bucket_aux_pack (u64 version, int use_count, int writer_flag)
97 {
98  return (version << (1 + CLIB_CUCKOO_USE_COUNT_BIT_WIDTH)) +
99  (use_count << 1) + writer_flag;
100 }
101 
102 always_inline clib_cuckoo_bucket_aux_t
103 clib_cuckoo_bucket_aux_set_version (clib_cuckoo_bucket_aux_t aux, u64 version)
104 {
105  int use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
106  int writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (aux);
107  return clib_cuckoo_bucket_aux_pack (version, use_count, writer_flag);
108 }
109 
110 always_inline clib_cuckoo_bucket_aux_t
111 clib_cuckoo_bucket_aux_set_use_count (clib_cuckoo_bucket_aux_t aux,
112  int use_count)
113 {
115  int writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (aux);
116  return clib_cuckoo_bucket_aux_pack (version, use_count, writer_flag);
117 }
118 
119 always_inline clib_cuckoo_bucket_aux_t
120 clib_cuckoo_bucket_aux_set_writer_flag (clib_cuckoo_bucket_aux_t aux,
121  int writer_flag)
122 {
124  int use_count = clib_cuckoo_bucket_aux_get_use_count (aux);
125  return clib_cuckoo_bucket_aux_pack (version, use_count, writer_flag);
126 }
127 
128 #define PATH_BITS_REQ \
129  (CLIB_CUCKOO_BFS_MAX_PATH_LENGTH * CLIB_CUCKOO_LOG2_KVP_PER_BUCKET)
130 
131 #if PATH_BITS_REQ <= 8
132 typedef u8 path_data_t;
133 #elif PATH_BITS_REQ <= 16
134 typedef u16 path_data_t;
135 #elif PATH_BITS_REQ <= 32
136 typedef u32 path_data_t;
137 #elif PATH_BITS_REQ <= 64
138 typedef u64 path_data_t;
139 #else
140 #error no suitable datatype for path storage...
141 #endif
142 
143 typedef struct
144 {
145  /** bucket where this path begins */
147  /** bucket at end of path */
149  /** length of the path */
151  /** holds compressed offsets in buckets along path */
152  path_data_t data;
154 
155 typedef struct
156 {
157  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
158 
159  /** reduced hashes corresponding to elements */
161 
162  /** auxiliary data - version, writer flag and used count */
163  volatile clib_cuckoo_bucket_aux_t aux;
164 
165  /** cuckoo elements in this bucket */
166  CVT (clib_cuckoo_kv) elts[CLIB_CUCKOO_KVP_PER_BUCKET];
167 } CVT (clib_cuckoo_bucket);
168 
169 #define clib_cuckoo_bucket_foreach_idx(var) \
170  for (var = 0; var < CLIB_CUCKOO_KVP_PER_BUCKET; var++)
171 
172 #if CLIB_CUCKOO_OPTIMIZE_UNROLL
173 #if CLIB_CUCKOO_KVP_PER_BUCKET == 2
174 #define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
175  do \
176  { \
177  var = 0; \
178  body; \
179  var = 1; \
180  body; \
181  } \
182  while (0);
183 #elif CLIB_CUCKOO_KVP_PER_BUCKET == 4
184 #define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
185  do \
186  { \
187  var = 0; \
188  body; \
189  var = 1; \
190  body; \
191  var = 2; \
192  body; \
193  var = 3; \
194  body; \
195  } \
196  while (0);
197 #elif CLIB_CUCKOO_KVP_PER_BUCKET == 8
198 #define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
199  do \
200  { \
201  var = 0; \
202  body; \
203  var = 1; \
204  body; \
205  var = 2; \
206  body; \
207  var = 3; \
208  body; \
209  var = 4; \
210  body; \
211  var = 5; \
212  body; \
213  var = 6; \
214  body; \
215  var = 7; \
216  body; \
217  } \
218  while (0);
219 #else
220 #define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
221  clib_cuckoo_bucket_foreach_idx (var) \
222  { \
223  body; \
224  }
225 #endif
226 #else /* CLIB_CUCKOO_OPTIMIZE_UNROLL */
227 #define clib_cuckoo_bucket_foreach_idx_unrolled(var, body) \
228  clib_cuckoo_bucket_foreach_idx (var) \
229  { \
230  body; \
231  }
232 #endif /* CLIB_CUCKOO_OPTIMIZE_UNROLL */
233 
234 #define clib_cuckoo_bucket_foreach_elt_index(var, bucket) \
235  for (var = 0; var < CLIB_CUCKOO_KVP_PER_BUCKET; ++i)
236 
237 #define clib_cuckoo_foreach_bucket(var, h, body) \
238  do \
239  { \
240  CVT (clib_cuckoo_bucket) *__buckets = h->buckets; \
241  vec_foreach (var, __buckets) \
242  { \
243  body; \
244  } \
245  } \
246  while (0)
247 
248 typedef struct CV (clib_cuckoo)
249 {
250  /** vector of elements containing key-value pairs and auxiliary data */
251  CVT (clib_cuckoo_bucket) * volatile buckets;
252 
253  /** garbage to be freed once its safe to do so .. */
254  CVT (clib_cuckoo_bucket) * *to_be_freed;
255 
256  /** hash table name */
257  const char *name;
258 
259  /** pool of cuckoo paths (reused when doing bfd search) */
260  clib_cuckoo_path_t *paths;
261 
262  /**
263  * vector used as queue when doing cuckoo path searches - holds offsets
264  * in paths pool
265  */
266  uword *bfs_search_queue;
267 
268  /**
269  * writer lock - whether this lock is taken or not has zero effect on
270  * readers
271  */
272  clib_spinlock_t writer_lock;
273 
274  /** caller context passed to callback with garbage notification */
275  void *garbage_ctx;
276 
277  /**
278  * garbage notify function - called when some garbage needs to be collected
279  * in main thread while other threads are stopped
280  */
281  void (*garbage_callback) (struct CV (clib_cuckoo) * h, void *garbage_ctx);
282 
283 #if CLIB_CUCKOO_DEBUG_COUNTERS
284  u64 steps_exceeded;
285  u64 bfs_queue_emptied;
286  u64 fast_adds;
287  u64 slow_adds;
288  u64 rehashes;
289 #endif
290 
291 } CVT (clib_cuckoo);
292 
293 void CV (clib_cuckoo_init) (CVT (clib_cuckoo) * h, const char *name,
294  uword nbuckets,
295  void (*garbage_callback) (CVT (clib_cuckoo) *,
296  void *),
297  void *garbage_ctx);
298 
299 void CV (clib_cuckoo_garbage_collect) (CVT (clib_cuckoo) * h);
300 
301 void CV (clib_cuckoo_free) (CVT (clib_cuckoo) * h);
302 
303 int CV (clib_cuckoo_add_del) (CVT (clib_cuckoo) * h,
304  CVT (clib_cuckoo_kv) * add_v, int is_add);
305 int CV (clib_cuckoo_search) (CVT (clib_cuckoo) * h,
306  CVT (clib_cuckoo_kv) * search_v,
307  CVT (clib_cuckoo_kv) * return_v);
308 
309 void CV (clib_cuckoo_foreach_key_value_pair) (CVT (clib_cuckoo) * h,
310  void *callback, void *arg);
311 
312 float CV (clib_cuckoo_calc_load) (CVT (clib_cuckoo) * h);
313 
315 format_function_t CV (format_cuckoo_kvp);
316 
319 {
320  u32 v32 = ((u32) hash) ^ ((u32) (hash >> 32));
321  u16 v16 = ((u16) v32) ^ ((u16) (v32 >> 16));
322  u8 v8 = ((u8) v16) ^ ((u8) (v16 >> 8));
323  return v8;
324 }
325 
327 clib_cuckoo_get_other_bucket (u64 nbuckets, u64 bucket, u8 reduced_hash)
328 {
329  u64 mask = (nbuckets - 1);
330  return (bucket ^ ((reduced_hash + 1) * 0xc6a4a7935bd1e995)) & mask;
331 }
332 
334 CV (clib_cuckoo_calc_lookup) (CVT (clib_cuckoo_bucket) * buckets, u64 hash)
335 {
337  u64 nbuckets = vec_len (buckets);
338  u64 mask = (nbuckets - 1);
339  lookup.bucket1 = hash & mask;
340 #if CLIB_CUCKOO_OPTIMIZE_PREFETCH
341  CLIB_PREFETCH (vec_elt_at_index (buckets, lookup.bucket1),
342  sizeof (*buckets), LOAD);
343 #endif
344  u8 reduced_hash = clib_cuckoo_reduce_hash (hash);
345  lookup.bucket2 =
346  clib_cuckoo_get_other_bucket (nbuckets, lookup.bucket1, reduced_hash);
347 #if CLIB_CUCKOO_OPTIMIZE_PREFETCH
348  CLIB_PREFETCH (vec_elt_at_index (buckets, lookup.bucket2),
349  sizeof (*buckets), LOAD);
350 #endif
351  lookup.reduced_hash = reduced_hash;
352  ASSERT (lookup.bucket1 < nbuckets);
353  ASSERT (lookup.bucket2 < nbuckets);
354  return lookup;
355 }
356 
357 /**
358  * search for key within bucket
359  */
360 always_inline int CV (clib_cuckoo_bucket_search) (CVT (clib_cuckoo_bucket) *
361  b,
362  CVT (clib_cuckoo_kv) * kvp,
363  u8 reduced_hash)
364 {
365  clib_cuckoo_bucket_aux_t bucket_aux;
366  u8 writer_flag;
367  do
368  {
369  bucket_aux = b->aux;
370  writer_flag = clib_cuckoo_bucket_aux_get_writer_flag (bucket_aux);
371  }
372  while (PREDICT_FALSE (writer_flag)); /* loop while writer flag is set */
373 
374  int i;
375 #if CLIB_CUCKOO_OPTIMIZE_USE_COUNT_LIMITS_SEARCH
376  const int use_count = clib_cuckoo_bucket_aux_get_use_count (bucket_aux);
377 #endif
378  /* *INDENT-OFF* */
380 #if CLIB_CUCKOO_OPTIMIZE_USE_COUNT_LIMITS_SEARCH
381  if (i > use_count)
382  {
383  break;
384  }
385 #endif
386  if (
388  reduced_hash == b->reduced_hashes[i] &&
389 #endif
390  0 == memcmp (&kvp->key, &b->elts[i].key, sizeof (kvp->key)))
391  {
392  kvp->value = b->elts[i].value;
393  clib_cuckoo_bucket_aux_t bucket_aux2 = b->aux;
394  if (PREDICT_TRUE (clib_cuckoo_bucket_aux_get_version (bucket_aux) ==
395  clib_cuckoo_bucket_aux_get_version (bucket_aux2)))
396  {
397  /* yay, fresh data */
398  return CLIB_CUCKOO_ERROR_SUCCESS;
399  }
400  else
401  {
402  /* oops, modification detected */
403  return CLIB_CUCKOO_ERROR_AGAIN;
404  }
405  }
406  });
407  /* *INDENT-ON* */
408  return CLIB_CUCKOO_ERROR_NOT_FOUND;
409 }
410 
412  CVT (clib_cuckoo_kv) * kvp)
413 {
415  int rv;
416 
417  u64 hash = CV (clib_cuckoo_hash) (kvp);
418  CVT (clib_cuckoo_bucket) * buckets;
419 again:
420  buckets = h->buckets;
421  lookup = CV (clib_cuckoo_calc_lookup) (buckets, hash);
422  do
423  {
424  rv =
426  (buckets, lookup.bucket1), kvp,
427  lookup.reduced_hash);
428  }
429  while (PREDICT_FALSE (CLIB_CUCKOO_ERROR_AGAIN == rv));
430  if (CLIB_CUCKOO_ERROR_SUCCESS == rv)
431  {
432  return CLIB_CUCKOO_ERROR_SUCCESS;
433  }
434 
435  rv =
437  (buckets, lookup.bucket2), kvp,
438  lookup.reduced_hash);
439  if (PREDICT_FALSE (CLIB_CUCKOO_ERROR_AGAIN == rv))
440  {
441  /*
442  * change to 2nd bucket could bump the item to 1st bucket and the bucket
443  * indexes might not even be valid anymore - restart the search
444  */
445  goto again;
446  }
447  return rv;
448 }
449 
450 #endif /* __included_cuckoo_template_h__ */
451 
452 /** @endcond */
453 
454 /*
455  * fd.io coding-style-patch-verification: ON
456  *
457  * Local Variables:
458  * eval: (c-set-style "gnu")
459  * End:
460  */
#define clib_cuckoo_bucket_foreach_idx_unrolled(var, body)
#define CLIB_CACHE_LINE_ALIGN_MARK(mark)
Definition: cache.h:60
int CV() clib_cuckoo_search(CVT(clib_cuckoo) *h, CVT(clib_cuckoo_kv) *search_v, CVT(clib_cuckoo_kv) *return_v)
u64 start
bucket where this path begins
unsigned long u64
Definition: types.h:89
volatile clib_cuckoo_bucket_aux_t aux
auxiliary data - version, writer flag and used count
u8 length
length of the path
Fixed length block allocator.
u8 v8
Definition: ikev2.h:27
u64 clib_cuckoo_bucket_aux_t
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")
static u64 clib_cuckoo_get_other_bucket(u64 nbuckets, u64 bucket, u8 reduced_hash)
int i
int CV() clib_cuckoo_add_del(CVT(clib_cuckoo) *h, CVT(clib_cuckoo_kv) *add_v, int is_add)
#define CLIB_CUCKOO_USE_COUNT_BIT_WIDTH
unsigned char u8
Definition: types.h:56
static u8 clib_cuckoo_reduce_hash(u64 hash)
#define CVT(a)
u8 *() format_function_t(u8 *s, va_list *args)
Definition: format.h:48
static clib_cuckoo_bucket_aux_t clib_cuckoo_bucket_aux_set_version(clib_cuckoo_bucket_aux_t aux, u64 version)
float CV() clib_cuckoo_calc_load(CVT(clib_cuckoo) *h)
void CV() clib_cuckoo_init(CVT(clib_cuckoo) *h, const char *name, uword nbuckets, void(*garbage_callback)(CVT(clib_cuckoo) *, void *), void *garbage_ctx)
#define always_inline
Definition: clib.h:98
#define vec_elt_at_index(v, i)
Get vector value at index i checking that i is in bounds.
static clib_cuckoo_bucket_aux_t clib_cuckoo_bucket_aux_set_use_count(clib_cuckoo_bucket_aux_t aux, int use_count)
unsigned int u32
Definition: types.h:88
static u64 clib_cuckoo_bucket_aux_get_version(clib_cuckoo_bucket_aux_t aux)
unsigned short u16
Definition: types.h:57
u64 bucket
bucket at end of path
#define PREDICT_FALSE(x)
Definition: clib.h:111
static int CV() clib_cuckoo_bucket_search(CVT(clib_cuckoo_bucket) *b, CVT(clib_cuckoo_kv) *kvp, u8 reduced_hash)
search for key within bucket
#define CLIB_CUCKOO_KVP_PER_BUCKET
Definition: cuckoo_8_8.h:18
u8 name[64]
Definition: memclnt.api:152
static hash_pair_t * lookup(void *v, uword key, enum lookup_opcode op, void *new_value, void *old_value)
Definition: hash.c:494
#define CV(a)
#define CLIB_PREFETCH(addr, size, type)
Definition: cache.h:79
static int clib_cuckoo_bucket_aux_get_use_count(clib_cuckoo_bucket_aux_t aux)
void CV() clib_cuckoo_foreach_key_value_pair(CVT(clib_cuckoo) *h, void *callback, void *arg)
u8 *CV() format_cuckoo(u8 *s, va_list *args)
#define ASSERT(truth)
void CV() clib_cuckoo_free(CVT(clib_cuckoo) *h)
#define CLIB_CUCKOO_LOG2_KVP_PER_BUCKET
Definition: cuckoo_8_8.h:19
static clib_cuckoo_bucket_aux_t clib_cuckoo_bucket_aux_set_writer_flag(clib_cuckoo_bucket_aux_t aux, int writer_flag)
option version
Definition: memclnt.api:17
static clib_cuckoo_lookup_info_t CV() clib_cuckoo_calc_lookup(CVT(clib_cuckoo_bucket) *buckets, u64 hash)
#define CLIB_CUCKOO_OPTIMIZE_CMP_REDUCED_HASH
Definition: cuckoo_8_8.h:38
static int CV() clib_cuckoo_search_inline(CVT(clib_cuckoo) *h, CVT(clib_cuckoo_kv) *kvp)
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
u64 uword
Definition: types.h:112
void CV() clib_cuckoo_garbage_collect(CVT(clib_cuckoo) *h)
perform garbage collection
path_data_t data
holds compressed offsets in buckets along path
u8 path_data_t
static int clib_cuckoo_bucket_aux_get_writer_flag(clib_cuckoo_bucket_aux_t aux)
static clib_cuckoo_bucket_aux_t clib_cuckoo_bucket_aux_pack(u64 version, int use_count, int writer_flag)