ceph/src/spdk/dpdk/test/test/test_barrier.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2018 Intel Corporation
   3  */
   4
   5  /*
   6   * This is a simple functional test for rte_smp_mb() implementation.
   7   * I.E. make sure that LOAD and STORE operations that precede the
   8   * rte_smp_mb() call are globally visible across the lcores
   9   * before the the LOAD and STORE operations that follows it.
  10   * The test uses simple implementation of Peterson's lock algorithm
  11   * (https://en.wikipedia.org/wiki/Peterson%27s_algorithm)
  12   * for two execution units to make sure that rte_smp_mb() prevents
  13   * store-load reordering to happen.
  14   * Also when executed on a single lcore could be used as a approxiamate
  15   * estimation of number of cycles particular implementation of rte_smp_mb()
  16   * will take.
  17   */
  18
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <stdint.h>
  22 #include <inttypes.h>
  23
  24 #include <rte_memory.h>
  25 #include <rte_per_lcore.h>
  26 #include <rte_launch.h>
  27 #include <rte_atomic.h>
  28 #include <rte_eal.h>
  29 #include <rte_lcore.h>
  30 #include <rte_pause.h>
  31 #include <rte_random.h>
  32 #include <rte_cycles.h>
  33 #include <rte_vect.h>
  34 #include <rte_debug.h>
  35
  36 #include "test.h"
  37
  38 #define ADD_MAX         8
  39 #define ITER_MAX        0x1000000
  40
  41 enum plock_use_type {
  42         USE_MB,
  43         USE_SMP_MB,
  44         USE_NUM
  45 };
  46
  47 struct plock {
  48         volatile uint32_t flag[2];
  49         volatile uint32_t victim;
  50         enum plock_use_type utype;
  51 };
  52
  53 /*
  54  * Lock plus protected by it two counters.
  55  */
  56 struct plock_test {
  57         struct plock lock;
  58         uint32_t val;
  59         uint32_t iter;
  60 };
  61
  62 /*
  63  * Each active lcore shares plock_test struct with it's left and right
  64  * neighbours.
  65  */
  66 struct lcore_plock_test {
  67         struct plock_test *pt[2]; /* shared, lock-protected data */
  68         uint32_t sum[2];          /* local copy of the shared data */
  69         uint32_t iter;            /* number of iterations to perfom */
  70         uint32_t lc;              /* given lcore id */
  71 };
  72
  73 static inline void
  74 store_load_barrier(uint32_t utype)
  75 {
  76         if (utype == USE_MB)
  77                 rte_mb();
  78         else if (utype == USE_SMP_MB)
  79                 rte_smp_mb();
  80         else
  81                 RTE_VERIFY(0);
  82 }
  83
  84 /*
  85  * Peterson lock implementation.
  86  */
  87 static void
  88 plock_lock(struct plock *l, uint32_t self)
  89 {
  90         uint32_t other;
  91
  92         other = self ^ 1;
  93
  94         l->flag[self] = 1;
  95         l->victim = self;
  96
  97         store_load_barrier(l->utype);
  98
  99         while (l->flag[other] == 1 && l->victim == self)
 100                 rte_pause();
 101 }
 102
 103 static void
 104 plock_unlock(struct plock *l, uint32_t self)
 105 {
 106         rte_smp_wmb();
 107         l->flag[self] = 0;
 108 }
 109
 110 static void
 111 plock_reset(struct plock *l, enum plock_use_type utype)
 112 {
 113         memset(l, 0, sizeof(*l));
 114         l->utype = utype;
 115 }
 116
 117 /*
 118  * grab the lock, update both counters, release the lock.
 119  */
 120 static void
 121 plock_add(struct plock_test *pt, uint32_t self, uint32_t n)
 122 {
 123         plock_lock(&pt->lock, self);
 124         pt->iter++;
 125         pt->val += n;
 126         plock_unlock(&pt->lock, self);
 127 }
 128
 129 static int
 130 plock_test1_lcore(void *data)
 131 {
 132         uint64_t tm;
 133         uint32_t i, lc, ln, n;
 134         struct lcore_plock_test *lpt;
 135
 136         lpt = data;
 137         lc = rte_lcore_id();
 138
 139         /* find lcore_plock_test struct for given lcore */
 140         for (ln = rte_lcore_count(); ln != 0 && lpt->lc != lc; lpt++, ln--)
 141                 ;
 142
 143         if (ln == 0) {
 144                 printf("%s(%u) error at init\n", __func__, lc);
 145                 return -1;
 146         }
 147
 148         n = rte_rand() % ADD_MAX;
 149         tm = rte_get_timer_cycles();
 150
 151         /*
 152          * for each iteration:
 153          * - update shared, locked protected data in a safe manner
 154          * - update local copy of the shared data
 155          */
 156         for (i = 0; i != lpt->iter; i++) {
 157
 158                 plock_add(lpt->pt[0], 0, n);
 159                 plock_add(lpt->pt[1], 1, n);
 160
 161                 lpt->sum[0] += n;
 162                 lpt->sum[1] += n;
 163
 164                 n = (n + 1) % ADD_MAX;
 165         }
 166
 167         tm = rte_get_timer_cycles() - tm;
 168
 169         printf("%s(%u): %u iterations finished, in %" PRIu64
 170                 " cycles, %#Lf cycles/iteration, "
 171                 "local sum={%u, %u}\n",
 172                 __func__, lc, i, tm, (long double)tm / i,
 173                 lpt->sum[0], lpt->sum[1]);
 174         return 0;
 175 }
 176
 177 /*
 178  * For N active lcores we allocate N+1 lcore_plock_test structures.
 179  * Each active lcore shares one lcore_plock_test structure with its
 180  * left lcore neighbor and one lcore_plock_test structure with its
 181  * right lcore neighbor.
 182  * During the test each lcore updates data in both shared structures and
 183  * its local copies. Then at validation phase we check that our shared
 184  * and local data are the same.
 185  */
 186 static int
 187 plock_test(uint32_t iter, enum plock_use_type utype)
 188 {
 189         int32_t rc;
 190         uint32_t i, lc, n;
 191         uint32_t *sum;
 192         struct plock_test *pt;
 193         struct lcore_plock_test *lpt;
 194
 195         /* init phase, allocate and initialize shared data */
 196
 197         n = rte_lcore_count();
 198         pt = calloc(n + 1, sizeof(*pt));
 199         lpt = calloc(n, sizeof(*lpt));
 200         sum = calloc(n + 1, sizeof(*sum));
 201
 202         printf("%s(iter=%u, utype=%u) started on %u lcores\n",
 203                 __func__, iter, utype, n);
 204
 205         if (pt == NULL || lpt == NULL) {
 206                 printf("%s: failed to allocate memory for %u lcores\n",
 207                         __func__, n);
 208                 free(pt);
 209                 free(lpt);
 210                 free(sum);
 211                 return -ENOMEM;
 212         }
 213
 214         for (i = 0; i != n + 1; i++)
 215                 plock_reset(&pt[i].lock, utype);
 216
 217         i = 0;
 218         RTE_LCORE_FOREACH(lc) {
 219
 220                 lpt[i].lc = lc;
 221                 lpt[i].iter = iter;
 222                 lpt[i].pt[0] = pt + i;
 223                 lpt[i].pt[1] = pt + i + 1;
 224                 i++;
 225         }
 226
 227         lpt[i - 1].pt[1] = pt;
 228
 229         for (i = 0; i != n; i++)
 230                 printf("lpt[%u]={lc=%u, pt={%p, %p},};\n",
 231                         i, lpt[i].lc, lpt[i].pt[0], lpt[i].pt[1]);
 232
 233
 234         /* test phase - start and wait for completion on each active lcore */
 235
 236         rte_eal_mp_remote_launch(plock_test1_lcore, lpt, CALL_MASTER);
 237         rte_eal_mp_wait_lcore();
 238
 239         /* validation phase - make sure that shared and local data match */
 240
 241         for (i = 0; i != n; i++) {
 242                 sum[i] += lpt[i].sum[0];
 243                 sum[i + 1] += lpt[i].sum[1];
 244         }
 245
 246         sum[0] += sum[i];
 247
 248         rc = 0;
 249         for (i = 0; i != n; i++) {
 250                 printf("%s: sum[%u]=%u, pt[%u].val=%u, pt[%u].iter=%u;\n",
 251                         __func__, i, sum[i], i, pt[i].val, i, pt[i].iter);
 252
 253                 /* race condition occurred, lock doesn't work properly */
 254                 if (sum[i] != pt[i].val || 2 * iter != pt[i].iter) {
 255                         printf("error: local and shared sums don't much\n");
 256                         rc = -1;
 257                 }
 258         }
 259
 260         free(pt);
 261         free(lpt);
 262         free(sum);
 263
 264         printf("%s(utype=%u) returns %d\n", __func__, utype, rc);
 265         return rc;
 266 }
 267
 268 static int
 269 test_barrier(void)
 270 {
 271         int32_t i, ret, rc[USE_NUM];
 272
 273         for (i = 0; i != RTE_DIM(rc); i++)
 274                 rc[i] = plock_test(ITER_MAX, i);
 275
 276         ret = 0;
 277         for (i = 0; i != RTE_DIM(rc); i++) {
 278                 printf("%s for utype=%d %s\n",
 279                         __func__, i, rc[i] == 0 ? "passed" : "failed");
 280                 ret |= rc[i];
 281         }
 282
 283         return ret;
 284 }
 285
 286 REGISTER_TEST_COMMAND(barrier_autotest, test_barrier);