lib/librte_distributor/rte_distributor_v20.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 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_memzone.h>
  11 #include <rte_errno.h>
  12 #include <rte_compat.h>
  13 #include <rte_string_fns.h>
  14 #include <rte_eal_memconfig.h>
  15 #include <rte_pause.h>
  16 #include <rte_tailq.h>
  17
  18 #include "rte_distributor_v20.h"
  19 #include "rte_distributor_private.h"
  20
  21 TAILQ_HEAD(rte_distributor_list, rte_distributor_v20);
  22
  23 static struct rte_tailq_elem rte_distributor_tailq = {
  24         .name = "RTE_DISTRIBUTOR",
  25 };
  26 EAL_REGISTER_TAILQ(rte_distributor_tailq)
  27
  28 /**** APIs called by workers ****/
  29
  30 void
  31 rte_distributor_request_pkt_v20(struct rte_distributor_v20 *d,
  32                 unsigned worker_id, struct rte_mbuf *oldpkt)
  33 {
  34         union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id];
  35         int64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
  36                         | RTE_DISTRIB_GET_BUF;
  37         while (unlikely(buf->bufptr64 & RTE_DISTRIB_FLAGS_MASK))
  38                 rte_pause();
  39         buf->bufptr64 = req;
  40 }
  41 VERSION_SYMBOL(rte_distributor_request_pkt, _v20, 2.0);
  42
  43 struct rte_mbuf *
  44 rte_distributor_poll_pkt_v20(struct rte_distributor_v20 *d,
  45                 unsigned worker_id)
  46 {
  47         union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id];
  48         if (buf->bufptr64 & RTE_DISTRIB_GET_BUF)
  49                 return NULL;
  50
  51         /* since bufptr64 is signed, this should be an arithmetic shift */
  52         int64_t ret = buf->bufptr64 >> RTE_DISTRIB_FLAG_BITS;
  53         return (struct rte_mbuf *)((uintptr_t)ret);
  54 }
  55 VERSION_SYMBOL(rte_distributor_poll_pkt, _v20, 2.0);
  56
  57 struct rte_mbuf *
  58 rte_distributor_get_pkt_v20(struct rte_distributor_v20 *d,
  59                 unsigned worker_id, struct rte_mbuf *oldpkt)
  60 {
  61         struct rte_mbuf *ret;
  62         rte_distributor_request_pkt_v20(d, worker_id, oldpkt);
  63         while ((ret = rte_distributor_poll_pkt_v20(d, worker_id)) == NULL)
  64                 rte_pause();
  65         return ret;
  66 }
  67 VERSION_SYMBOL(rte_distributor_get_pkt, _v20, 2.0);
  68
  69 int
  70 rte_distributor_return_pkt_v20(struct rte_distributor_v20 *d,
  71                 unsigned worker_id, struct rte_mbuf *oldpkt)
  72 {
  73         union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id];
  74         uint64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
  75                         | RTE_DISTRIB_RETURN_BUF;
  76         buf->bufptr64 = req;
  77         return 0;
  78 }
  79 VERSION_SYMBOL(rte_distributor_return_pkt, _v20, 2.0);
  80
  81 /**** APIs called on distributor core ***/
  82
  83 /* as name suggests, adds a packet to the backlog for a particular worker */
  84 static int
  85 add_to_backlog(struct rte_distributor_backlog *bl, int64_t item)
  86 {
  87         if (bl->count == RTE_DISTRIB_BACKLOG_SIZE)
  88                 return -1;
  89
  90         bl->pkts[(bl->start + bl->count++) & (RTE_DISTRIB_BACKLOG_MASK)]
  91                         = item;
  92         return 0;
  93 }
  94
  95 /* takes the next packet for a worker off the backlog */
  96 static int64_t
  97 backlog_pop(struct rte_distributor_backlog *bl)
  98 {
  99         bl->count--;
 100         return bl->pkts[bl->start++ & RTE_DISTRIB_BACKLOG_MASK];
 101 }
 102
 103 /* stores a packet returned from a worker inside the returns array */
 104 static inline void
 105 store_return(uintptr_t oldbuf, struct rte_distributor_v20 *d,
 106                 unsigned *ret_start, unsigned *ret_count)
 107 {
 108         /* store returns in a circular buffer - code is branch-free */
 109         d->returns.mbufs[(*ret_start + *ret_count) & RTE_DISTRIB_RETURNS_MASK]
 110                         = (void *)oldbuf;
 111         *ret_start += (*ret_count == RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
 112         *ret_count += (*ret_count != RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
 113 }
 114
 115 static inline void
 116 handle_worker_shutdown(struct rte_distributor_v20 *d, unsigned int wkr)
 117 {
 118         d->in_flight_tags[wkr] = 0;
 119         d->in_flight_bitmask &= ~(1UL << wkr);
 120         d->bufs[wkr].bufptr64 = 0;
 121         if (unlikely(d->backlog[wkr].count != 0)) {
 122                 /* On return of a packet, we need to move the
 123                  * queued packets for this core elsewhere.
 124                  * Easiest solution is to set things up for
 125                  * a recursive call. That will cause those
 126                  * packets to be queued up for the next free
 127                  * core, i.e. it will return as soon as a
 128                  * core becomes free to accept the first
 129                  * packet, as subsequent ones will be added to
 130                  * the backlog for that core.
 131                  */
 132                 struct rte_mbuf *pkts[RTE_DISTRIB_BACKLOG_SIZE];
 133                 unsigned i;
 134                 struct rte_distributor_backlog *bl = &d->backlog[wkr];
 135
 136                 for (i = 0; i < bl->count; i++) {
 137                         unsigned idx = (bl->start + i) &
 138                                         RTE_DISTRIB_BACKLOG_MASK;
 139                         pkts[i] = (void *)((uintptr_t)(bl->pkts[idx] >>
 140                                         RTE_DISTRIB_FLAG_BITS));
 141                 }
 142                 /* recursive call.
 143                  * Note that the tags were set before first level call
 144                  * to rte_distributor_process.
 145                  */
 146                 rte_distributor_process_v20(d, pkts, i);
 147                 bl->count = bl->start = 0;
 148         }
 149 }
 150
 151 /* this function is called when process() fn is called without any new
 152  * packets. It goes through all the workers and clears any returned packets
 153  * to do a partial flush.
 154  */
 155 static int
 156 process_returns(struct rte_distributor_v20 *d)
 157 {
 158         unsigned wkr;
 159         unsigned flushed = 0;
 160         unsigned ret_start = d->returns.start,
 161                         ret_count = d->returns.count;
 162
 163         for (wkr = 0; wkr < d->num_workers; wkr++) {
 164
 165                 const int64_t data = d->bufs[wkr].bufptr64;
 166                 uintptr_t oldbuf = 0;
 167
 168                 if (data & RTE_DISTRIB_GET_BUF) {
 169                         flushed++;
 170                         if (d->backlog[wkr].count)
 171                                 d->bufs[wkr].bufptr64 =
 172                                                 backlog_pop(&d->backlog[wkr]);
 173                         else {
 174                                 d->bufs[wkr].bufptr64 = RTE_DISTRIB_GET_BUF;
 175                                 d->in_flight_tags[wkr] = 0;
 176                                 d->in_flight_bitmask &= ~(1UL << wkr);
 177                         }
 178                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 179                 } else if (data & RTE_DISTRIB_RETURN_BUF) {
 180                         handle_worker_shutdown(d, wkr);
 181                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 182                 }
 183
 184                 store_return(oldbuf, d, &ret_start, &ret_count);
 185         }
 186
 187         d->returns.start = ret_start;
 188         d->returns.count = ret_count;
 189
 190         return flushed;
 191 }
 192
 193 /* process a set of packets to distribute them to workers */
 194 int
 195 rte_distributor_process_v20(struct rte_distributor_v20 *d,
 196                 struct rte_mbuf **mbufs, unsigned num_mbufs)
 197 {
 198         unsigned next_idx = 0;
 199         unsigned wkr = 0;
 200         struct rte_mbuf *next_mb = NULL;
 201         int64_t next_value = 0;
 202         uint32_t new_tag = 0;
 203         unsigned ret_start = d->returns.start,
 204                         ret_count = d->returns.count;
 205
 206         if (unlikely(num_mbufs == 0))
 207                 return process_returns(d);
 208
 209         while (next_idx < num_mbufs || next_mb != NULL) {
 210
 211                 int64_t data = d->bufs[wkr].bufptr64;
 212                 uintptr_t oldbuf = 0;
 213
 214                 if (!next_mb) {
 215                         next_mb = mbufs[next_idx++];
 216                         next_value = (((int64_t)(uintptr_t)next_mb)
 217                                         << RTE_DISTRIB_FLAG_BITS);
 218                         /*
 219                          * User is advocated to set tag value for each
 220                          * mbuf before calling rte_distributor_process.
 221                          * User defined tags are used to identify flows,
 222                          * or sessions.
 223                          */
 224                         new_tag = next_mb->hash.usr;
 225
 226                         /*
 227                          * Note that if RTE_DISTRIB_MAX_WORKERS is larger than 64
 228                          * then the size of match has to be expanded.
 229                          */
 230                         uint64_t match = 0;
 231                         unsigned i;
 232                         /*
 233                          * to scan for a match use "xor" and "not" to get a 0/1
 234                          * value, then use shifting to merge to single "match"
 235                          * variable, where a one-bit indicates a match for the
 236                          * worker given by the bit-position
 237                          */
 238                         for (i = 0; i < d->num_workers; i++)
 239                                 match |= (!(d->in_flight_tags[i] ^ new_tag)
 240                                         << i);
 241
 242                         /* Only turned-on bits are considered as match */
 243                         match &= d->in_flight_bitmask;
 244
 245                         if (match) {
 246                                 next_mb = NULL;
 247                                 unsigned worker = __builtin_ctzl(match);
 248                                 if (add_to_backlog(&d->backlog[worker],
 249                                                 next_value) < 0)
 250                                         next_idx--;
 251                         }
 252                 }
 253
 254                 if ((data & RTE_DISTRIB_GET_BUF) &&
 255                                 (d->backlog[wkr].count || next_mb)) {
 256
 257                         if (d->backlog[wkr].count)
 258                                 d->bufs[wkr].bufptr64 =
 259                                                 backlog_pop(&d->backlog[wkr]);
 260
 261                         else {
 262                                 d->bufs[wkr].bufptr64 = next_value;
 263                                 d->in_flight_tags[wkr] = new_tag;
 264                                 d->in_flight_bitmask |= (1UL << wkr);
 265                                 next_mb = NULL;
 266                         }
 267                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 268                 } else if (data & RTE_DISTRIB_RETURN_BUF) {
 269                         handle_worker_shutdown(d, wkr);
 270                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 271                 }
 272
 273                 /* store returns in a circular buffer */
 274                 store_return(oldbuf, d, &ret_start, &ret_count);
 275
 276                 if (++wkr == d->num_workers)
 277                         wkr = 0;
 278         }
 279         /* to finish, check all workers for backlog and schedule work for them
 280          * if they are ready */
 281         for (wkr = 0; wkr < d->num_workers; wkr++)
 282                 if (d->backlog[wkr].count &&
 283                                 (d->bufs[wkr].bufptr64 & RTE_DISTRIB_GET_BUF)) {
 284
 285                         int64_t oldbuf = d->bufs[wkr].bufptr64 >>
 286                                         RTE_DISTRIB_FLAG_BITS;
 287                         store_return(oldbuf, d, &ret_start, &ret_count);
 288
 289                         d->bufs[wkr].bufptr64 = backlog_pop(&d->backlog[wkr]);
 290                 }
 291
 292         d->returns.start = ret_start;
 293         d->returns.count = ret_count;
 294         return num_mbufs;
 295 }
 296 VERSION_SYMBOL(rte_distributor_process, _v20, 2.0);
 297
 298 /* return to the caller, packets returned from workers */
 299 int
 300 rte_distributor_returned_pkts_v20(struct rte_distributor_v20 *d,
 301                 struct rte_mbuf **mbufs, unsigned max_mbufs)
 302 {
 303         struct rte_distributor_returned_pkts *returns = &d->returns;
 304         unsigned retval = (max_mbufs < returns->count) ?
 305                         max_mbufs : returns->count;
 306         unsigned i;
 307
 308         for (i = 0; i < retval; i++) {
 309                 unsigned idx = (returns->start + i) & RTE_DISTRIB_RETURNS_MASK;
 310                 mbufs[i] = returns->mbufs[idx];
 311         }
 312         returns->start += i;
 313         returns->count -= i;
 314
 315         return retval;
 316 }
 317 VERSION_SYMBOL(rte_distributor_returned_pkts, _v20, 2.0);
 318
 319 /* return the number of packets in-flight in a distributor, i.e. packets
 320  * being worked on or queued up in a backlog.
 321  */
 322 static inline unsigned
 323 total_outstanding(const struct rte_distributor_v20 *d)
 324 {
 325         unsigned wkr, total_outstanding;
 326
 327         total_outstanding = __builtin_popcountl(d->in_flight_bitmask);
 328
 329         for (wkr = 0; wkr < d->num_workers; wkr++)
 330                 total_outstanding += d->backlog[wkr].count;
 331
 332         return total_outstanding;
 333 }
 334
 335 /* flush the distributor, so that there are no outstanding packets in flight or
 336  * queued up. */
 337 int
 338 rte_distributor_flush_v20(struct rte_distributor_v20 *d)
 339 {
 340         const unsigned flushed = total_outstanding(d);
 341
 342         while (total_outstanding(d) > 0)
 343                 rte_distributor_process_v20(d, NULL, 0);
 344
 345         return flushed;
 346 }
 347 VERSION_SYMBOL(rte_distributor_flush, _v20, 2.0);
 348
 349 /* clears the internal returns array in the distributor */
 350 void
 351 rte_distributor_clear_returns_v20(struct rte_distributor_v20 *d)
 352 {
 353         d->returns.start = d->returns.count = 0;
 354 #ifndef __OPTIMIZE__
 355         memset(d->returns.mbufs, 0, sizeof(d->returns.mbufs));
 356 #endif
 357 }
 358 VERSION_SYMBOL(rte_distributor_clear_returns, _v20, 2.0);
 359
 360 /* creates a distributor instance */
 361 struct rte_distributor_v20 *
 362 rte_distributor_create_v20(const char *name,
 363                 unsigned socket_id,
 364                 unsigned num_workers)
 365 {
 366         struct rte_distributor_v20 *d;
 367         struct rte_distributor_list *distributor_list;
 368         char mz_name[RTE_MEMZONE_NAMESIZE];
 369         const struct rte_memzone *mz;
 370
 371         /* compilation-time checks */
 372         RTE_BUILD_BUG_ON((sizeof(*d) & RTE_CACHE_LINE_MASK) != 0);
 373         RTE_BUILD_BUG_ON((RTE_DISTRIB_MAX_WORKERS & 7) != 0);
 374         RTE_BUILD_BUG_ON(RTE_DISTRIB_MAX_WORKERS >
 375                                 sizeof(d->in_flight_bitmask) * CHAR_BIT);
 376
 377         if (name == NULL || num_workers >= RTE_DISTRIB_MAX_WORKERS) {
 378                 rte_errno = EINVAL;
 379                 return NULL;
 380         }
 381
 382         snprintf(mz_name, sizeof(mz_name), RTE_DISTRIB_PREFIX"%s", name);
 383         mz = rte_memzone_reserve(mz_name, sizeof(*d), socket_id, NO_FLAGS);
 384         if (mz == NULL) {
 385                 rte_errno = ENOMEM;
 386                 return NULL;
 387         }
 388
 389         d = mz->addr;
 390         strlcpy(d->name, name, sizeof(d->name));
 391         d->num_workers = num_workers;
 392
 393         distributor_list = RTE_TAILQ_CAST(rte_distributor_tailq.head,
 394                                           rte_distributor_list);
 395
 396         rte_mcfg_tailq_write_lock();
 397         TAILQ_INSERT_TAIL(distributor_list, d, next);
 398         rte_mcfg_tailq_write_unlock();
 399
 400         return d;
 401 }
 402 VERSION_SYMBOL(rte_distributor_create, _v20, 2.0);