New upstream version 18.02
[deb_dpdk.git] / lib / librte_distributor / rte_distributor.c
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2017 Intel Corporation
3  */
4
5 #include <stdio.h>
6 #include <sys/queue.h>
7 #include <string.h>
8 #include <rte_mbuf.h>
9 #include <rte_memory.h>
10 #include <rte_cycles.h>
11 #include <rte_compat.h>
12 #include <rte_memzone.h>
13 #include <rte_errno.h>
14 #include <rte_string_fns.h>
15 #include <rte_eal_memconfig.h>
16 #include <rte_pause.h>
17
18 #include "rte_distributor_private.h"
19 #include "rte_distributor.h"
20 #include "rte_distributor_v20.h"
21 #include "rte_distributor_v1705.h"
22
23 TAILQ_HEAD(rte_dist_burst_list, rte_distributor);
24
25 static struct rte_tailq_elem rte_dist_burst_tailq = {
26         .name = "RTE_DIST_BURST",
27 };
28 EAL_REGISTER_TAILQ(rte_dist_burst_tailq)
29
30 /**** APIs called by workers ****/
31
32 /**** Burst Packet APIs called by workers ****/
33
34 void
35 rte_distributor_request_pkt_v1705(struct rte_distributor *d,
36                 unsigned int worker_id, struct rte_mbuf **oldpkt,
37                 unsigned int count)
38 {
39         struct rte_distributor_buffer *buf = &(d->bufs[worker_id]);
40         unsigned int i;
41
42         volatile int64_t *retptr64;
43
44         if (unlikely(d->alg_type == RTE_DIST_ALG_SINGLE)) {
45                 rte_distributor_request_pkt_v20(d->d_v20,
46                         worker_id, oldpkt[0]);
47                 return;
48         }
49
50         retptr64 = &(buf->retptr64[0]);
51         /* Spin while handshake bits are set (scheduler clears it) */
52         while (unlikely(*retptr64 & RTE_DISTRIB_GET_BUF)) {
53                 rte_pause();
54                 uint64_t t = rte_rdtsc()+100;
55
56                 while (rte_rdtsc() < t)
57                         rte_pause();
58         }
59
60         /*
61          * OK, if we've got here, then the scheduler has just cleared the
62          * handshake bits. Populate the retptrs with returning packets.
63          */
64
65         for (i = count; i < RTE_DIST_BURST_SIZE; i++)
66                 buf->retptr64[i] = 0;
67
68         /* Set Return bit for each packet returned */
69         for (i = count; i-- > 0; )
70                 buf->retptr64[i] =
71                         (((int64_t)(uintptr_t)(oldpkt[i])) <<
72                         RTE_DISTRIB_FLAG_BITS) | RTE_DISTRIB_RETURN_BUF;
73
74         /*
75          * Finally, set the GET_BUF  to signal to distributor that cache
76          * line is ready for processing
77          */
78         *retptr64 |= RTE_DISTRIB_GET_BUF;
79 }
80 BIND_DEFAULT_SYMBOL(rte_distributor_request_pkt, _v1705, 17.05);
81 MAP_STATIC_SYMBOL(void rte_distributor_request_pkt(struct rte_distributor *d,
82                 unsigned int worker_id, struct rte_mbuf **oldpkt,
83                 unsigned int count),
84                 rte_distributor_request_pkt_v1705);
85
86 int
87 rte_distributor_poll_pkt_v1705(struct rte_distributor *d,
88                 unsigned int worker_id, struct rte_mbuf **pkts)
89 {
90         struct rte_distributor_buffer *buf = &d->bufs[worker_id];
91         uint64_t ret;
92         int count = 0;
93         unsigned int i;
94
95         if (unlikely(d->alg_type == RTE_DIST_ALG_SINGLE)) {
96                 pkts[0] = rte_distributor_poll_pkt_v20(d->d_v20, worker_id);
97                 return (pkts[0]) ? 1 : 0;
98         }
99
100         /* If bit is set, return */
101         if (buf->bufptr64[0] & RTE_DISTRIB_GET_BUF)
102                 return -1;
103
104         /* since bufptr64 is signed, this should be an arithmetic shift */
105         for (i = 0; i < RTE_DIST_BURST_SIZE; i++) {
106                 if (likely(buf->bufptr64[i] & RTE_DISTRIB_VALID_BUF)) {
107                         ret = buf->bufptr64[i] >> RTE_DISTRIB_FLAG_BITS;
108                         pkts[count++] = (struct rte_mbuf *)((uintptr_t)(ret));
109                 }
110         }
111
112         /*
113          * so now we've got the contents of the cacheline into an  array of
114          * mbuf pointers, so toggle the bit so scheduler can start working
115          * on the next cacheline while we're working.
116          */
117         buf->bufptr64[0] |= RTE_DISTRIB_GET_BUF;
118
119         return count;
120 }
121 BIND_DEFAULT_SYMBOL(rte_distributor_poll_pkt, _v1705, 17.05);
122 MAP_STATIC_SYMBOL(int rte_distributor_poll_pkt(struct rte_distributor *d,
123                 unsigned int worker_id, struct rte_mbuf **pkts),
124                 rte_distributor_poll_pkt_v1705);
125
126 int
127 rte_distributor_get_pkt_v1705(struct rte_distributor *d,
128                 unsigned int worker_id, struct rte_mbuf **pkts,
129                 struct rte_mbuf **oldpkt, unsigned int return_count)
130 {
131         int count;
132
133         if (unlikely(d->alg_type == RTE_DIST_ALG_SINGLE)) {
134                 if (return_count <= 1) {
135                         pkts[0] = rte_distributor_get_pkt_v20(d->d_v20,
136                                 worker_id, oldpkt[0]);
137                         return (pkts[0]) ? 1 : 0;
138                 } else
139                         return -EINVAL;
140         }
141
142         rte_distributor_request_pkt(d, worker_id, oldpkt, return_count);
143
144         count = rte_distributor_poll_pkt(d, worker_id, pkts);
145         while (count == -1) {
146                 uint64_t t = rte_rdtsc() + 100;
147
148                 while (rte_rdtsc() < t)
149                         rte_pause();
150
151                 count = rte_distributor_poll_pkt(d, worker_id, pkts);
152         }
153         return count;
154 }
155 BIND_DEFAULT_SYMBOL(rte_distributor_get_pkt, _v1705, 17.05);
156 MAP_STATIC_SYMBOL(int rte_distributor_get_pkt(struct rte_distributor *d,
157                 unsigned int worker_id, struct rte_mbuf **pkts,
158                 struct rte_mbuf **oldpkt, unsigned int return_count),
159                 rte_distributor_get_pkt_v1705);
160
161 int
162 rte_distributor_return_pkt_v1705(struct rte_distributor *d,
163                 unsigned int worker_id, struct rte_mbuf **oldpkt, int num)
164 {
165         struct rte_distributor_buffer *buf = &d->bufs[worker_id];
166         unsigned int i;
167
168         if (unlikely(d->alg_type == RTE_DIST_ALG_SINGLE)) {
169                 if (num == 1)
170                         return rte_distributor_return_pkt_v20(d->d_v20,
171                                 worker_id, oldpkt[0]);
172                 else
173                         return -EINVAL;
174         }
175
176         for (i = 0; i < RTE_DIST_BURST_SIZE; i++)
177                 /* Switch off the return bit first */
178                 buf->retptr64[i] &= ~RTE_DISTRIB_RETURN_BUF;
179
180         for (i = num; i-- > 0; )
181                 buf->retptr64[i] = (((int64_t)(uintptr_t)oldpkt[i]) <<
182                         RTE_DISTRIB_FLAG_BITS) | RTE_DISTRIB_RETURN_BUF;
183
184         /* set the GET_BUF but even if we got no returns */
185         buf->retptr64[0] |= RTE_DISTRIB_GET_BUF;
186
187         return 0;
188 }
189 BIND_DEFAULT_SYMBOL(rte_distributor_return_pkt, _v1705, 17.05);
190 MAP_STATIC_SYMBOL(int rte_distributor_return_pkt(struct rte_distributor *d,
191                 unsigned int worker_id, struct rte_mbuf **oldpkt, int num),
192                 rte_distributor_return_pkt_v1705);
193
194 /**** APIs called on distributor core ***/
195
196 /* stores a packet returned from a worker inside the returns array */
197 static inline void
198 store_return(uintptr_t oldbuf, struct rte_distributor *d,
199                 unsigned int *ret_start, unsigned int *ret_count)
200 {
201         if (!oldbuf)
202                 return;
203         /* store returns in a circular buffer */
204         d->returns.mbufs[(*ret_start + *ret_count) & RTE_DISTRIB_RETURNS_MASK]
205                         = (void *)oldbuf;
206         *ret_start += (*ret_count == RTE_DISTRIB_RETURNS_MASK);
207         *ret_count += (*ret_count != RTE_DISTRIB_RETURNS_MASK);
208 }
209
210 /*
211  * Match then flow_ids (tags) of the incoming packets to the flow_ids
212  * of the inflight packets (both inflight on the workers and in each worker
213  * backlog). This will then allow us to pin those packets to the relevant
214  * workers to give us our atomic flow pinning.
215  */
216 void
217 find_match_scalar(struct rte_distributor *d,
218                         uint16_t *data_ptr,
219                         uint16_t *output_ptr)
220 {
221         struct rte_distributor_backlog *bl;
222         uint16_t i, j, w;
223
224         /*
225          * Function overview:
226          * 1. Loop through all worker ID's
227          * 2. Compare the current inflights to the incoming tags
228          * 3. Compare the current backlog to the incoming tags
229          * 4. Add any matches to the output
230          */
231
232         for (j = 0 ; j < RTE_DIST_BURST_SIZE; j++)
233                 output_ptr[j] = 0;
234
235         for (i = 0; i < d->num_workers; i++) {
236                 bl = &d->backlog[i];
237
238                 for (j = 0; j < RTE_DIST_BURST_SIZE ; j++)
239                         for (w = 0; w < RTE_DIST_BURST_SIZE; w++)
240                                 if (d->in_flight_tags[i][j] == data_ptr[w]) {
241                                         output_ptr[j] = i+1;
242                                         break;
243                                 }
244                 for (j = 0; j < RTE_DIST_BURST_SIZE; j++)
245                         for (w = 0; w < RTE_DIST_BURST_SIZE; w++)
246                                 if (bl->tags[j] == data_ptr[w]) {
247                                         output_ptr[j] = i+1;
248                                         break;
249                                 }
250         }
251
252         /*
253          * At this stage, the output contains 8 16-bit values, with
254          * each non-zero value containing the worker ID on which the
255          * corresponding flow is pinned to.
256          */
257 }
258
259
260 /*
261  * When the handshake bits indicate that there are packets coming
262  * back from the worker, this function is called to copy and store
263  * the valid returned pointers (store_return).
264  */
265 static unsigned int
266 handle_returns(struct rte_distributor *d, unsigned int wkr)
267 {
268         struct rte_distributor_buffer *buf = &(d->bufs[wkr]);
269         uintptr_t oldbuf;
270         unsigned int ret_start = d->returns.start,
271                         ret_count = d->returns.count;
272         unsigned int count = 0;
273         unsigned int i;
274
275         if (buf->retptr64[0] & RTE_DISTRIB_GET_BUF) {
276                 for (i = 0; i < RTE_DIST_BURST_SIZE; i++) {
277                         if (buf->retptr64[i] & RTE_DISTRIB_RETURN_BUF) {
278                                 oldbuf = ((uintptr_t)(buf->retptr64[i] >>
279                                         RTE_DISTRIB_FLAG_BITS));
280                                 /* store returns in a circular buffer */
281                                 store_return(oldbuf, d, &ret_start, &ret_count);
282                                 count++;
283                                 buf->retptr64[i] &= ~RTE_DISTRIB_RETURN_BUF;
284                         }
285                 }
286                 d->returns.start = ret_start;
287                 d->returns.count = ret_count;
288                 /* Clear for the worker to populate with more returns */
289                 buf->retptr64[0] = 0;
290         }
291         return count;
292 }
293
294 /*
295  * This function releases a burst (cache line) to a worker.
296  * It is called from the process function when a cacheline is
297  * full to make room for more packets for that worker, or when
298  * all packets have been assigned to bursts and need to be flushed
299  * to the workers.
300  * It also needs to wait for any outstanding packets from the worker
301  * before sending out new packets.
302  */
303 static unsigned int
304 release(struct rte_distributor *d, unsigned int wkr)
305 {
306         struct rte_distributor_buffer *buf = &(d->bufs[wkr]);
307         unsigned int i;
308
309         while (!(d->bufs[wkr].bufptr64[0] & RTE_DISTRIB_GET_BUF))
310                 rte_pause();
311
312         handle_returns(d, wkr);
313
314         buf->count = 0;
315
316         for (i = 0; i < d->backlog[wkr].count; i++) {
317                 d->bufs[wkr].bufptr64[i] = d->backlog[wkr].pkts[i] |
318                                 RTE_DISTRIB_GET_BUF | RTE_DISTRIB_VALID_BUF;
319                 d->in_flight_tags[wkr][i] = d->backlog[wkr].tags[i];
320         }
321         buf->count = i;
322         for ( ; i < RTE_DIST_BURST_SIZE ; i++) {
323                 buf->bufptr64[i] = RTE_DISTRIB_GET_BUF;
324                 d->in_flight_tags[wkr][i] = 0;
325         }
326
327         d->backlog[wkr].count = 0;
328
329         /* Clear the GET bit */
330         buf->bufptr64[0] &= ~RTE_DISTRIB_GET_BUF;
331         return  buf->count;
332
333 }
334
335
336 /* process a set of packets to distribute them to workers */
337 int
338 rte_distributor_process_v1705(struct rte_distributor *d,
339                 struct rte_mbuf **mbufs, unsigned int num_mbufs)
340 {
341         unsigned int next_idx = 0;
342         static unsigned int wkr;
343         struct rte_mbuf *next_mb = NULL;
344         int64_t next_value = 0;
345         uint16_t new_tag = 0;
346         uint16_t flows[RTE_DIST_BURST_SIZE] __rte_cache_aligned;
347         unsigned int i, j, w, wid;
348
349         if (d->alg_type == RTE_DIST_ALG_SINGLE) {
350                 /* Call the old API */
351                 return rte_distributor_process_v20(d->d_v20, mbufs, num_mbufs);
352         }
353
354         if (unlikely(num_mbufs == 0)) {
355                 /* Flush out all non-full cache-lines to workers. */
356                 for (wid = 0 ; wid < d->num_workers; wid++) {
357                         if (d->bufs[wid].bufptr64[0] & RTE_DISTRIB_GET_BUF) {
358                                 release(d, wid);
359                                 handle_returns(d, wid);
360                         }
361                 }
362                 return 0;
363         }
364
365         while (next_idx < num_mbufs) {
366                 uint16_t matches[RTE_DIST_BURST_SIZE];
367                 unsigned int pkts;
368
369                 if (d->bufs[wkr].bufptr64[0] & RTE_DISTRIB_GET_BUF)
370                         d->bufs[wkr].count = 0;
371
372                 if ((num_mbufs - next_idx) < RTE_DIST_BURST_SIZE)
373                         pkts = num_mbufs - next_idx;
374                 else
375                         pkts = RTE_DIST_BURST_SIZE;
376
377                 for (i = 0; i < pkts; i++) {
378                         if (mbufs[next_idx + i]) {
379                                 /* flows have to be non-zero */
380                                 flows[i] = mbufs[next_idx + i]->hash.usr | 1;
381                         } else
382                                 flows[i] = 0;
383                 }
384                 for (; i < RTE_DIST_BURST_SIZE; i++)
385                         flows[i] = 0;
386
387                 switch (d->dist_match_fn) {
388                 case RTE_DIST_MATCH_VECTOR:
389                         find_match_vec(d, &flows[0], &matches[0]);
390                         break;
391                 default:
392                         find_match_scalar(d, &flows[0], &matches[0]);
393                 }
394
395                 /*
396                  * Matches array now contain the intended worker ID (+1) of
397                  * the incoming packets. Any zeroes need to be assigned
398                  * workers.
399                  */
400
401                 for (j = 0; j < pkts; j++) {
402
403                         next_mb = mbufs[next_idx++];
404                         next_value = (((int64_t)(uintptr_t)next_mb) <<
405                                         RTE_DISTRIB_FLAG_BITS);
406                         /*
407                          * User is advocated to set tag value for each
408                          * mbuf before calling rte_distributor_process.
409                          * User defined tags are used to identify flows,
410                          * or sessions.
411                          */
412                         /* flows MUST be non-zero */
413                         new_tag = (uint16_t)(next_mb->hash.usr) | 1;
414
415                         /*
416                          * Uncommenting the next line will cause the find_match
417                          * function to be optimized out, making this function
418                          * do parallel (non-atomic) distribution
419                          */
420                         /* matches[j] = 0; */
421
422                         if (matches[j]) {
423                                 struct rte_distributor_backlog *bl =
424                                                 &d->backlog[matches[j]-1];
425                                 if (unlikely(bl->count ==
426                                                 RTE_DIST_BURST_SIZE)) {
427                                         release(d, matches[j]-1);
428                                 }
429
430                                 /* Add to worker that already has flow */
431                                 unsigned int idx = bl->count++;
432
433                                 bl->tags[idx] = new_tag;
434                                 bl->pkts[idx] = next_value;
435
436                         } else {
437                                 struct rte_distributor_backlog *bl =
438                                                 &d->backlog[wkr];
439                                 if (unlikely(bl->count ==
440                                                 RTE_DIST_BURST_SIZE)) {
441                                         release(d, wkr);
442                                 }
443
444                                 /* Add to current worker worker */
445                                 unsigned int idx = bl->count++;
446
447                                 bl->tags[idx] = new_tag;
448                                 bl->pkts[idx] = next_value;
449                                 /*
450                                  * Now that we've just added an unpinned flow
451                                  * to a worker, we need to ensure that all
452                                  * other packets with that same flow will go
453                                  * to the same worker in this burst.
454                                  */
455                                 for (w = j; w < pkts; w++)
456                                         if (flows[w] == new_tag)
457                                                 matches[w] = wkr+1;
458                         }
459                 }
460                 wkr++;
461                 if (wkr >= d->num_workers)
462                         wkr = 0;
463         }
464
465         /* Flush out all non-full cache-lines to workers. */
466         for (wid = 0 ; wid < d->num_workers; wid++)
467                 if ((d->bufs[wid].bufptr64[0] & RTE_DISTRIB_GET_BUF))
468                         release(d, wid);
469
470         return num_mbufs;
471 }
472 BIND_DEFAULT_SYMBOL(rte_distributor_process, _v1705, 17.05);
473 MAP_STATIC_SYMBOL(int rte_distributor_process(struct rte_distributor *d,
474                 struct rte_mbuf **mbufs, unsigned int num_mbufs),
475                 rte_distributor_process_v1705);
476
477 /* return to the caller, packets returned from workers */
478 int
479 rte_distributor_returned_pkts_v1705(struct rte_distributor *d,
480                 struct rte_mbuf **mbufs, unsigned int max_mbufs)
481 {
482         struct rte_distributor_returned_pkts *returns = &d->returns;
483         unsigned int retval = (max_mbufs < returns->count) ?
484                         max_mbufs : returns->count;
485         unsigned int i;
486
487         if (d->alg_type == RTE_DIST_ALG_SINGLE) {
488                 /* Call the old API */
489                 return rte_distributor_returned_pkts_v20(d->d_v20,
490                                 mbufs, max_mbufs);
491         }
492
493         for (i = 0; i < retval; i++) {
494                 unsigned int idx = (returns->start + i) &
495                                 RTE_DISTRIB_RETURNS_MASK;
496
497                 mbufs[i] = returns->mbufs[idx];
498         }
499         returns->start += i;
500         returns->count -= i;
501
502         return retval;
503 }
504 BIND_DEFAULT_SYMBOL(rte_distributor_returned_pkts, _v1705, 17.05);
505 MAP_STATIC_SYMBOL(int rte_distributor_returned_pkts(struct rte_distributor *d,
506                 struct rte_mbuf **mbufs, unsigned int max_mbufs),
507                 rte_distributor_returned_pkts_v1705);
508
509 /*
510  * Return the number of packets in-flight in a distributor, i.e. packets
511  * being worked on or queued up in a backlog.
512  */
513 static inline unsigned int
514 total_outstanding(const struct rte_distributor *d)
515 {
516         unsigned int wkr, total_outstanding = 0;
517
518         for (wkr = 0; wkr < d->num_workers; wkr++)
519                 total_outstanding += d->backlog[wkr].count;
520
521         return total_outstanding;
522 }
523
524 /*
525  * Flush the distributor, so that there are no outstanding packets in flight or
526  * queued up.
527  */
528 int
529 rte_distributor_flush_v1705(struct rte_distributor *d)
530 {
531         unsigned int flushed;
532         unsigned int wkr;
533
534         if (d->alg_type == RTE_DIST_ALG_SINGLE) {
535                 /* Call the old API */
536                 return rte_distributor_flush_v20(d->d_v20);
537         }
538
539         flushed = total_outstanding(d);
540
541         while (total_outstanding(d) > 0)
542                 rte_distributor_process(d, NULL, 0);
543
544         /*
545          * Send empty burst to all workers to allow them to exit
546          * gracefully, should they need to.
547          */
548         rte_distributor_process(d, NULL, 0);
549
550         for (wkr = 0; wkr < d->num_workers; wkr++)
551                 handle_returns(d, wkr);
552
553         return flushed;
554 }
555 BIND_DEFAULT_SYMBOL(rte_distributor_flush, _v1705, 17.05);
556 MAP_STATIC_SYMBOL(int rte_distributor_flush(struct rte_distributor *d),
557                 rte_distributor_flush_v1705);
558
559 /* clears the internal returns array in the distributor */
560 void
561 rte_distributor_clear_returns_v1705(struct rte_distributor *d)
562 {
563         unsigned int wkr;
564
565         if (d->alg_type == RTE_DIST_ALG_SINGLE) {
566                 /* Call the old API */
567                 rte_distributor_clear_returns_v20(d->d_v20);
568                 return;
569         }
570
571         /* throw away returns, so workers can exit */
572         for (wkr = 0; wkr < d->num_workers; wkr++)
573                 d->bufs[wkr].retptr64[0] = 0;
574 }
575 BIND_DEFAULT_SYMBOL(rte_distributor_clear_returns, _v1705, 17.05);
576 MAP_STATIC_SYMBOL(void rte_distributor_clear_returns(struct rte_distributor *d),
577                 rte_distributor_clear_returns_v1705);
578
579 /* creates a distributor instance */
580 struct rte_distributor *
581 rte_distributor_create_v1705(const char *name,
582                 unsigned int socket_id,
583                 unsigned int num_workers,
584                 unsigned int alg_type)
585 {
586         struct rte_distributor *d;
587         struct rte_dist_burst_list *dist_burst_list;
588         char mz_name[RTE_MEMZONE_NAMESIZE];
589         const struct rte_memzone *mz;
590         unsigned int i;
591
592         /* TODO Reorganise function properly around RTE_DIST_ALG_SINGLE/BURST */
593
594         /* compilation-time checks */
595         RTE_BUILD_BUG_ON((sizeof(*d) & RTE_CACHE_LINE_MASK) != 0);
596         RTE_BUILD_BUG_ON((RTE_DISTRIB_MAX_WORKERS & 7) != 0);
597
598         if (alg_type == RTE_DIST_ALG_SINGLE) {
599                 d = malloc(sizeof(struct rte_distributor));
600                 if (d == NULL) {
601                         rte_errno = ENOMEM;
602                         return NULL;
603                 }
604                 d->d_v20 = rte_distributor_create_v20(name,
605                                 socket_id, num_workers);
606                 if (d->d_v20 == NULL) {
607                         free(d);
608                         /* rte_errno will have been set */
609                         return NULL;
610                 }
611                 d->alg_type = alg_type;
612                 return d;
613         }
614
615         if (name == NULL || num_workers >= RTE_DISTRIB_MAX_WORKERS) {
616                 rte_errno = EINVAL;
617                 return NULL;
618         }
619
620         snprintf(mz_name, sizeof(mz_name), RTE_DISTRIB_PREFIX"%s", name);
621         mz = rte_memzone_reserve(mz_name, sizeof(*d), socket_id, NO_FLAGS);
622         if (mz == NULL) {
623                 rte_errno = ENOMEM;
624                 return NULL;
625         }
626
627         d = mz->addr;
628         snprintf(d->name, sizeof(d->name), "%s", name);
629         d->num_workers = num_workers;
630         d->alg_type = alg_type;
631
632         d->dist_match_fn = RTE_DIST_MATCH_SCALAR;
633 #if defined(RTE_ARCH_X86)
634         d->dist_match_fn = RTE_DIST_MATCH_VECTOR;
635 #endif
636
637         /*
638          * Set up the backlog tags so they're pointing at the second cache
639          * line for performance during flow matching
640          */
641         for (i = 0 ; i < num_workers ; i++)
642                 d->backlog[i].tags = &d->in_flight_tags[i][RTE_DIST_BURST_SIZE];
643
644         dist_burst_list = RTE_TAILQ_CAST(rte_dist_burst_tailq.head,
645                                           rte_dist_burst_list);
646
647
648         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
649         TAILQ_INSERT_TAIL(dist_burst_list, d, next);
650         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
651
652         return d;
653 }
654 BIND_DEFAULT_SYMBOL(rte_distributor_create, _v1705, 17.05);
655 MAP_STATIC_SYMBOL(struct rte_distributor *rte_distributor_create(
656                 const char *name, unsigned int socket_id,
657                 unsigned int num_workers, unsigned int alg_type),
658                 rte_distributor_create_v1705);