lib/librte_distributor/rte_distributor_v20.c

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   5  *   All rights reserved.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following conditions
   9  *   are met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <stdio.h>
  35 #include <sys/queue.h>
  36 #include <string.h>
  37 #include <rte_mbuf.h>
  38 #include <rte_memory.h>
  39 #include <rte_memzone.h>
  40 #include <rte_errno.h>
  41 #include <rte_compat.h>
  42 #include <rte_string_fns.h>
  43 #include <rte_eal_memconfig.h>
  44 #include <rte_pause.h>
  45
  46 #include "rte_distributor_v20.h"
  47 #include "rte_distributor_private.h"
  48
  49 TAILQ_HEAD(rte_distributor_list, rte_distributor_v20);
  50
  51 static struct rte_tailq_elem rte_distributor_tailq = {
  52         .name = "RTE_DISTRIBUTOR",
  53 };
  54 EAL_REGISTER_TAILQ(rte_distributor_tailq)
  55
  56 /**** APIs called by workers ****/
  57
  58 void
  59 rte_distributor_request_pkt_v20(struct rte_distributor_v20 *d,
  60                 unsigned worker_id, struct rte_mbuf *oldpkt)
  61 {
  62         union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id];
  63         int64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
  64                         | RTE_DISTRIB_GET_BUF;
  65         while (unlikely(buf->bufptr64 & RTE_DISTRIB_FLAGS_MASK))
  66                 rte_pause();
  67         buf->bufptr64 = req;
  68 }
  69 VERSION_SYMBOL(rte_distributor_request_pkt, _v20, 2.0);
  70
  71 struct rte_mbuf *
  72 rte_distributor_poll_pkt_v20(struct rte_distributor_v20 *d,
  73                 unsigned worker_id)
  74 {
  75         union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id];
  76         if (buf->bufptr64 & RTE_DISTRIB_GET_BUF)
  77                 return NULL;
  78
  79         /* since bufptr64 is signed, this should be an arithmetic shift */
  80         int64_t ret = buf->bufptr64 >> RTE_DISTRIB_FLAG_BITS;
  81         return (struct rte_mbuf *)((uintptr_t)ret);
  82 }
  83 VERSION_SYMBOL(rte_distributor_poll_pkt, _v20, 2.0);
  84
  85 struct rte_mbuf *
  86 rte_distributor_get_pkt_v20(struct rte_distributor_v20 *d,
  87                 unsigned worker_id, struct rte_mbuf *oldpkt)
  88 {
  89         struct rte_mbuf *ret;
  90         rte_distributor_request_pkt_v20(d, worker_id, oldpkt);
  91         while ((ret = rte_distributor_poll_pkt_v20(d, worker_id)) == NULL)
  92                 rte_pause();
  93         return ret;
  94 }
  95 VERSION_SYMBOL(rte_distributor_get_pkt, _v20, 2.0);
  96
  97 int
  98 rte_distributor_return_pkt_v20(struct rte_distributor_v20 *d,
  99                 unsigned worker_id, struct rte_mbuf *oldpkt)
 100 {
 101         union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id];
 102         uint64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS)
 103                         | RTE_DISTRIB_RETURN_BUF;
 104         buf->bufptr64 = req;
 105         return 0;
 106 }
 107 VERSION_SYMBOL(rte_distributor_return_pkt, _v20, 2.0);
 108
 109 /**** APIs called on distributor core ***/
 110
 111 /* as name suggests, adds a packet to the backlog for a particular worker */
 112 static int
 113 add_to_backlog(struct rte_distributor_backlog *bl, int64_t item)
 114 {
 115         if (bl->count == RTE_DISTRIB_BACKLOG_SIZE)
 116                 return -1;
 117
 118         bl->pkts[(bl->start + bl->count++) & (RTE_DISTRIB_BACKLOG_MASK)]
 119                         = item;
 120         return 0;
 121 }
 122
 123 /* takes the next packet for a worker off the backlog */
 124 static int64_t
 125 backlog_pop(struct rte_distributor_backlog *bl)
 126 {
 127         bl->count--;
 128         return bl->pkts[bl->start++ & RTE_DISTRIB_BACKLOG_MASK];
 129 }
 130
 131 /* stores a packet returned from a worker inside the returns array */
 132 static inline void
 133 store_return(uintptr_t oldbuf, struct rte_distributor_v20 *d,
 134                 unsigned *ret_start, unsigned *ret_count)
 135 {
 136         /* store returns in a circular buffer - code is branch-free */
 137         d->returns.mbufs[(*ret_start + *ret_count) & RTE_DISTRIB_RETURNS_MASK]
 138                         = (void *)oldbuf;
 139         *ret_start += (*ret_count == RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
 140         *ret_count += (*ret_count != RTE_DISTRIB_RETURNS_MASK) & !!(oldbuf);
 141 }
 142
 143 static inline void
 144 handle_worker_shutdown(struct rte_distributor_v20 *d, unsigned int wkr)
 145 {
 146         d->in_flight_tags[wkr] = 0;
 147         d->in_flight_bitmask &= ~(1UL << wkr);
 148         d->bufs[wkr].bufptr64 = 0;
 149         if (unlikely(d->backlog[wkr].count != 0)) {
 150                 /* On return of a packet, we need to move the
 151                  * queued packets for this core elsewhere.
 152                  * Easiest solution is to set things up for
 153                  * a recursive call. That will cause those
 154                  * packets to be queued up for the next free
 155                  * core, i.e. it will return as soon as a
 156                  * core becomes free to accept the first
 157                  * packet, as subsequent ones will be added to
 158                  * the backlog for that core.
 159                  */
 160                 struct rte_mbuf *pkts[RTE_DISTRIB_BACKLOG_SIZE];
 161                 unsigned i;
 162                 struct rte_distributor_backlog *bl = &d->backlog[wkr];
 163
 164                 for (i = 0; i < bl->count; i++) {
 165                         unsigned idx = (bl->start + i) &
 166                                         RTE_DISTRIB_BACKLOG_MASK;
 167                         pkts[i] = (void *)((uintptr_t)(bl->pkts[idx] >>
 168                                         RTE_DISTRIB_FLAG_BITS));
 169                 }
 170                 /* recursive call.
 171                  * Note that the tags were set before first level call
 172                  * to rte_distributor_process.
 173                  */
 174                 rte_distributor_process_v20(d, pkts, i);
 175                 bl->count = bl->start = 0;
 176         }
 177 }
 178
 179 /* this function is called when process() fn is called without any new
 180  * packets. It goes through all the workers and clears any returned packets
 181  * to do a partial flush.
 182  */
 183 static int
 184 process_returns(struct rte_distributor_v20 *d)
 185 {
 186         unsigned wkr;
 187         unsigned flushed = 0;
 188         unsigned ret_start = d->returns.start,
 189                         ret_count = d->returns.count;
 190
 191         for (wkr = 0; wkr < d->num_workers; wkr++) {
 192
 193                 const int64_t data = d->bufs[wkr].bufptr64;
 194                 uintptr_t oldbuf = 0;
 195
 196                 if (data & RTE_DISTRIB_GET_BUF) {
 197                         flushed++;
 198                         if (d->backlog[wkr].count)
 199                                 d->bufs[wkr].bufptr64 =
 200                                                 backlog_pop(&d->backlog[wkr]);
 201                         else {
 202                                 d->bufs[wkr].bufptr64 = RTE_DISTRIB_GET_BUF;
 203                                 d->in_flight_tags[wkr] = 0;
 204                                 d->in_flight_bitmask &= ~(1UL << wkr);
 205                         }
 206                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 207                 } else if (data & RTE_DISTRIB_RETURN_BUF) {
 208                         handle_worker_shutdown(d, wkr);
 209                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 210                 }
 211
 212                 store_return(oldbuf, d, &ret_start, &ret_count);
 213         }
 214
 215         d->returns.start = ret_start;
 216         d->returns.count = ret_count;
 217
 218         return flushed;
 219 }
 220
 221 /* process a set of packets to distribute them to workers */
 222 int
 223 rte_distributor_process_v20(struct rte_distributor_v20 *d,
 224                 struct rte_mbuf **mbufs, unsigned num_mbufs)
 225 {
 226         unsigned next_idx = 0;
 227         unsigned wkr = 0;
 228         struct rte_mbuf *next_mb = NULL;
 229         int64_t next_value = 0;
 230         uint32_t new_tag = 0;
 231         unsigned ret_start = d->returns.start,
 232                         ret_count = d->returns.count;
 233
 234         if (unlikely(num_mbufs == 0))
 235                 return process_returns(d);
 236
 237         while (next_idx < num_mbufs || next_mb != NULL) {
 238
 239                 int64_t data = d->bufs[wkr].bufptr64;
 240                 uintptr_t oldbuf = 0;
 241
 242                 if (!next_mb) {
 243                         next_mb = mbufs[next_idx++];
 244                         next_value = (((int64_t)(uintptr_t)next_mb)
 245                                         << RTE_DISTRIB_FLAG_BITS);
 246                         /*
 247                          * User is advocated to set tag value for each
 248                          * mbuf before calling rte_distributor_process.
 249                          * User defined tags are used to identify flows,
 250                          * or sessions.
 251                          */
 252                         new_tag = next_mb->hash.usr;
 253
 254                         /*
 255                          * Note that if RTE_DISTRIB_MAX_WORKERS is larger than 64
 256                          * then the size of match has to be expanded.
 257                          */
 258                         uint64_t match = 0;
 259                         unsigned i;
 260                         /*
 261                          * to scan for a match use "xor" and "not" to get a 0/1
 262                          * value, then use shifting to merge to single "match"
 263                          * variable, where a one-bit indicates a match for the
 264                          * worker given by the bit-position
 265                          */
 266                         for (i = 0; i < d->num_workers; i++)
 267                                 match |= (!(d->in_flight_tags[i] ^ new_tag)
 268                                         << i);
 269
 270                         /* Only turned-on bits are considered as match */
 271                         match &= d->in_flight_bitmask;
 272
 273                         if (match) {
 274                                 next_mb = NULL;
 275                                 unsigned worker = __builtin_ctzl(match);
 276                                 if (add_to_backlog(&d->backlog[worker],
 277                                                 next_value) < 0)
 278                                         next_idx--;
 279                         }
 280                 }
 281
 282                 if ((data & RTE_DISTRIB_GET_BUF) &&
 283                                 (d->backlog[wkr].count || next_mb)) {
 284
 285                         if (d->backlog[wkr].count)
 286                                 d->bufs[wkr].bufptr64 =
 287                                                 backlog_pop(&d->backlog[wkr]);
 288
 289                         else {
 290                                 d->bufs[wkr].bufptr64 = next_value;
 291                                 d->in_flight_tags[wkr] = new_tag;
 292                                 d->in_flight_bitmask |= (1UL << wkr);
 293                                 next_mb = NULL;
 294                         }
 295                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 296                 } else if (data & RTE_DISTRIB_RETURN_BUF) {
 297                         handle_worker_shutdown(d, wkr);
 298                         oldbuf = data >> RTE_DISTRIB_FLAG_BITS;
 299                 }
 300
 301                 /* store returns in a circular buffer */
 302                 store_return(oldbuf, d, &ret_start, &ret_count);
 303
 304                 if (++wkr == d->num_workers)
 305                         wkr = 0;
 306         }
 307         /* to finish, check all workers for backlog and schedule work for them
 308          * if they are ready */
 309         for (wkr = 0; wkr < d->num_workers; wkr++)
 310                 if (d->backlog[wkr].count &&
 311                                 (d->bufs[wkr].bufptr64 & RTE_DISTRIB_GET_BUF)) {
 312
 313                         int64_t oldbuf = d->bufs[wkr].bufptr64 >>
 314                                         RTE_DISTRIB_FLAG_BITS;
 315                         store_return(oldbuf, d, &ret_start, &ret_count);
 316
 317                         d->bufs[wkr].bufptr64 = backlog_pop(&d->backlog[wkr]);
 318                 }
 319
 320         d->returns.start = ret_start;
 321         d->returns.count = ret_count;
 322         return num_mbufs;
 323 }
 324 VERSION_SYMBOL(rte_distributor_process, _v20, 2.0);
 325
 326 /* return to the caller, packets returned from workers */
 327 int
 328 rte_distributor_returned_pkts_v20(struct rte_distributor_v20 *d,
 329                 struct rte_mbuf **mbufs, unsigned max_mbufs)
 330 {
 331         struct rte_distributor_returned_pkts *returns = &d->returns;
 332         unsigned retval = (max_mbufs < returns->count) ?
 333                         max_mbufs : returns->count;
 334         unsigned i;
 335
 336         for (i = 0; i < retval; i++) {
 337                 unsigned idx = (returns->start + i) & RTE_DISTRIB_RETURNS_MASK;
 338                 mbufs[i] = returns->mbufs[idx];
 339         }
 340         returns->start += i;
 341         returns->count -= i;
 342
 343         return retval;
 344 }
 345 VERSION_SYMBOL(rte_distributor_returned_pkts, _v20, 2.0);
 346
 347 /* return the number of packets in-flight in a distributor, i.e. packets
 348  * being workered on or queued up in a backlog. */
 349 static inline unsigned
 350 total_outstanding(const struct rte_distributor_v20 *d)
 351 {
 352         unsigned wkr, total_outstanding;
 353
 354         total_outstanding = __builtin_popcountl(d->in_flight_bitmask);
 355
 356         for (wkr = 0; wkr < d->num_workers; wkr++)
 357                 total_outstanding += d->backlog[wkr].count;
 358
 359         return total_outstanding;
 360 }
 361
 362 /* flush the distributor, so that there are no outstanding packets in flight or
 363  * queued up. */
 364 int
 365 rte_distributor_flush_v20(struct rte_distributor_v20 *d)
 366 {
 367         const unsigned flushed = total_outstanding(d);
 368
 369         while (total_outstanding(d) > 0)
 370                 rte_distributor_process_v20(d, NULL, 0);
 371
 372         return flushed;
 373 }
 374 VERSION_SYMBOL(rte_distributor_flush, _v20, 2.0);
 375
 376 /* clears the internal returns array in the distributor */
 377 void
 378 rte_distributor_clear_returns_v20(struct rte_distributor_v20 *d)
 379 {
 380         d->returns.start = d->returns.count = 0;
 381 #ifndef __OPTIMIZE__
 382         memset(d->returns.mbufs, 0, sizeof(d->returns.mbufs));
 383 #endif
 384 }
 385 VERSION_SYMBOL(rte_distributor_clear_returns, _v20, 2.0);
 386
 387 /* creates a distributor instance */
 388 struct rte_distributor_v20 *
 389 rte_distributor_create_v20(const char *name,
 390                 unsigned socket_id,
 391                 unsigned num_workers)
 392 {
 393         struct rte_distributor_v20 *d;
 394         struct rte_distributor_list *distributor_list;
 395         char mz_name[RTE_MEMZONE_NAMESIZE];
 396         const struct rte_memzone *mz;
 397
 398         /* compilation-time checks */
 399         RTE_BUILD_BUG_ON((sizeof(*d) & RTE_CACHE_LINE_MASK) != 0);
 400         RTE_BUILD_BUG_ON((RTE_DISTRIB_MAX_WORKERS & 7) != 0);
 401         RTE_BUILD_BUG_ON(RTE_DISTRIB_MAX_WORKERS >
 402                                 sizeof(d->in_flight_bitmask) * CHAR_BIT);
 403
 404         if (name == NULL || num_workers >= RTE_DISTRIB_MAX_WORKERS) {
 405                 rte_errno = EINVAL;
 406                 return NULL;
 407         }
 408
 409         snprintf(mz_name, sizeof(mz_name), RTE_DISTRIB_PREFIX"%s", name);
 410         mz = rte_memzone_reserve(mz_name, sizeof(*d), socket_id, NO_FLAGS);
 411         if (mz == NULL) {
 412                 rte_errno = ENOMEM;
 413                 return NULL;
 414         }
 415
 416         d = mz->addr;
 417         snprintf(d->name, sizeof(d->name), "%s", name);
 418         d->num_workers = num_workers;
 419
 420         distributor_list = RTE_TAILQ_CAST(rte_distributor_tailq.head,
 421                                           rte_distributor_list);
 422
 423         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 424         TAILQ_INSERT_TAIL(distributor_list, d, next);
 425         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 426
 427         return d;
 428 }
 429 VERSION_SYMBOL(rte_distributor_create, _v20, 2.0);