tests/test-rcu-list.c

   1 /*
   2  * rcuq_test.c
   3  *
   4  * usage: rcuq_test <readers> <duration>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  * Copyright (c) 2013 Mike D. Day, IBM Corporation.
  21  */
  22
  23 #include <glib.h>
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include "qemu/atomic.h"
  28 #include "qemu/rcu.h"
  29 #include "qemu/compiler.h"
  30 #include "qemu/osdep.h"
  31 #include "qemu/thread.h"
  32 #include "qemu/rcu_queue.h"
  33
  34 /*
  35  * Test variables.
  36  */
  37
  38 static QemuMutex counts_mutex;
  39 static long long n_reads = 0LL;
  40 static long long n_updates = 0LL;
  41 static long long n_reclaims = 0LL;
  42 static long long n_nodes_removed = 0LL;
  43 static long long n_nodes = 0LL;
  44 static int g_test_in_charge = 0;
  45
  46 static int nthreadsrunning;
  47
  48 #define GOFLAG_INIT 0
  49 #define GOFLAG_RUN  1
  50 #define GOFLAG_STOP 2
  51
  52 static volatile int goflag = GOFLAG_INIT;
  53
  54 #define RCU_READ_RUN 1000
  55 #define RCU_UPDATE_RUN 10
  56 #define NR_THREADS 100
  57 #define RCU_Q_LEN 100
  58
  59 static QemuThread threads[NR_THREADS];
  60 static struct rcu_reader_data *data[NR_THREADS];
  61 static int n_threads;
  62
  63 static int select_random_el(int max)
  64 {
  65     return (rand() % max);
  66 }
  67
  68
  69 static void create_thread(void *(*func)(void *))
  70 {
  71     if (n_threads >= NR_THREADS) {
  72         fprintf(stderr, "Thread limit of %d exceeded!\n", NR_THREADS);
  73         exit(-1);
  74     }
  75     qemu_thread_create(&threads[n_threads], "test", func, &data[n_threads],
  76                        QEMU_THREAD_JOINABLE);
  77     n_threads++;
  78 }
  79
  80 static void wait_all_threads(void)
  81 {
  82     int i;
  83
  84     for (i = 0; i < n_threads; i++) {
  85         qemu_thread_join(&threads[i]);
  86     }
  87     n_threads = 0;
  88 }
  89
  90
  91 struct list_element {
  92     QLIST_ENTRY(list_element) entry;
  93     struct rcu_head rcu;
  94 };
  95
  96 static void reclaim_list_el(struct rcu_head *prcu)
  97 {
  98     struct list_element *el = container_of(prcu, struct list_element, rcu);
  99     g_free(el);
 100     /* Accessed only from call_rcu thread.  */
 101     n_reclaims++;
 102 }
 103
 104 static QLIST_HEAD(q_list_head, list_element) Q_list_head;
 105
 106 static void *rcu_q_reader(void *arg)
 107 {
 108     long long n_reads_local = 0;
 109     struct list_element *el;
 110
 111     rcu_register_thread();
 112
 113     *(struct rcu_reader_data **)arg = &rcu_reader;
 114     atomic_inc(&nthreadsrunning);
 115     while (goflag == GOFLAG_INIT) {
 116         g_usleep(1000);
 117     }
 118
 119     while (goflag == GOFLAG_RUN) {
 120         rcu_read_lock();
 121         QLIST_FOREACH_RCU(el, &Q_list_head, entry) {
 122             n_reads_local++;
 123             if (goflag == GOFLAG_STOP) {
 124                 break;
 125             }
 126         }
 127         rcu_read_unlock();
 128
 129         g_usleep(100);
 130     }
 131     qemu_mutex_lock(&counts_mutex);
 132     n_reads += n_reads_local;
 133     qemu_mutex_unlock(&counts_mutex);
 134
 135     rcu_unregister_thread();
 136     return NULL;
 137 }
 138
 139
 140 static void *rcu_q_updater(void *arg)
 141 {
 142     int j, target_el;
 143     long long n_nodes_local = 0;
 144     long long n_updates_local = 0;
 145     long long n_removed_local = 0;
 146     struct list_element *el, *prev_el;
 147
 148     *(struct rcu_reader_data **)arg = &rcu_reader;
 149     atomic_inc(&nthreadsrunning);
 150     while (goflag == GOFLAG_INIT) {
 151         g_usleep(1000);
 152     }
 153
 154     while (goflag == GOFLAG_RUN) {
 155         target_el = select_random_el(RCU_Q_LEN);
 156         j = 0;
 157         /* FOREACH_RCU could work here but let's use both macros */
 158         QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) {
 159             j++;
 160             if (target_el == j) {
 161                 QLIST_REMOVE_RCU(prev_el, entry);
 162                 /* may be more than one updater in the future */
 163                 call_rcu1(&prev_el->rcu, reclaim_list_el);
 164                 n_removed_local++;
 165                 break;
 166             }
 167         }
 168         if (goflag == GOFLAG_STOP) {
 169             break;
 170         }
 171         target_el = select_random_el(RCU_Q_LEN);
 172         j = 0;
 173         QLIST_FOREACH_RCU(el, &Q_list_head, entry) {
 174             j++;
 175             if (target_el == j) {
 176                 prev_el = g_new(struct list_element, 1);
 177                 n_nodes += n_nodes_local;
 178                 QLIST_INSERT_BEFORE_RCU(el, prev_el, entry);
 179                 break;
 180             }
 181         }
 182
 183         n_updates_local += 2;
 184         synchronize_rcu();
 185     }
 186     synchronize_rcu();
 187     qemu_mutex_lock(&counts_mutex);
 188     n_nodes += n_nodes_local;
 189     n_updates += n_updates_local;
 190     n_nodes_removed += n_removed_local;
 191     qemu_mutex_unlock(&counts_mutex);
 192     return NULL;
 193 }
 194
 195 static void rcu_qtest_init(void)
 196 {
 197     struct list_element *new_el;
 198     int i;
 199     nthreadsrunning = 0;
 200     srand(time(0));
 201     for (i = 0; i < RCU_Q_LEN; i++) {
 202         new_el = g_new(struct list_element, 1);
 203         QLIST_INSERT_HEAD_RCU(&Q_list_head, new_el, entry);
 204     }
 205     qemu_mutex_lock(&counts_mutex);
 206     n_nodes += RCU_Q_LEN;
 207     qemu_mutex_unlock(&counts_mutex);
 208 }
 209
 210 static void rcu_qtest_run(int duration, int nreaders)
 211 {
 212     int nthreads = nreaders + 1;
 213     while (atomic_read(&nthreadsrunning) < nthreads) {
 214         g_usleep(1000);
 215     }
 216
 217     goflag = GOFLAG_RUN;
 218     sleep(duration);
 219     goflag = GOFLAG_STOP;
 220     wait_all_threads();
 221 }
 222
 223
 224 static void rcu_qtest(const char *test, int duration, int nreaders)
 225 {
 226     int i;
 227     long long n_removed_local = 0;
 228
 229     struct list_element *el, *prev_el;
 230
 231     rcu_qtest_init();
 232     for (i = 0; i < nreaders; i++) {
 233         create_thread(rcu_q_reader);
 234     }
 235     create_thread(rcu_q_updater);
 236     rcu_qtest_run(duration, nreaders);
 237
 238     QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) {
 239         QLIST_REMOVE_RCU(prev_el, entry);
 240         call_rcu1(&prev_el->rcu, reclaim_list_el);
 241         n_removed_local++;
 242     }
 243     qemu_mutex_lock(&counts_mutex);
 244     n_nodes_removed += n_removed_local;
 245     qemu_mutex_unlock(&counts_mutex);
 246     synchronize_rcu();
 247     while (n_nodes_removed > n_reclaims) {
 248         g_usleep(100);
 249         synchronize_rcu();
 250     }
 251     if (g_test_in_charge) {
 252         g_assert_cmpint(n_nodes_removed, ==, n_reclaims);
 253     } else {
 254         printf("%s: %d readers; 1 updater; nodes read: "  \
 255                "%lld, nodes removed: %lld; nodes reclaimed: %lld\n",
 256                test, nthreadsrunning - 1, n_reads, n_nodes_removed, n_reclaims);
 257         exit(0);
 258     }
 259 }
 260
 261 static void usage(int argc, char *argv[])
 262 {
 263     fprintf(stderr, "Usage: %s duration nreaders\n", argv[0]);
 264     exit(-1);
 265 }
 266
 267 static int gtest_seconds;
 268
 269 static void gtest_rcuq_one(void)
 270 {
 271     rcu_qtest("rcuqtest", gtest_seconds / 4, 1);
 272 }
 273
 274 static void gtest_rcuq_few(void)
 275 {
 276     rcu_qtest("rcuqtest", gtest_seconds / 4, 5);
 277 }
 278
 279 static void gtest_rcuq_many(void)
 280 {
 281     rcu_qtest("rcuqtest", gtest_seconds / 2, 20);
 282 }
 283
 284
 285 int main(int argc, char *argv[])
 286 {
 287     int duration = 0, readers = 0;
 288
 289     qemu_mutex_init(&counts_mutex);
 290     if (argc >= 2) {
 291         if (argv[1][0] == '-') {
 292             g_test_init(&argc, &argv, NULL);
 293             if (g_test_quick()) {
 294                 gtest_seconds = 4;
 295             } else {
 296                 gtest_seconds = 20;
 297             }
 298             g_test_add_func("/rcu/qlist/single-threaded", gtest_rcuq_one);
 299             g_test_add_func("/rcu/qlist/short-few", gtest_rcuq_few);
 300             g_test_add_func("/rcu/qlist/long-many", gtest_rcuq_many);
 301             g_test_in_charge = 1;
 302             return g_test_run();
 303         }
 304         duration = strtoul(argv[1], NULL, 0);
 305     }
 306     if (argc >= 3) {
 307         readers = strtoul(argv[2], NULL, 0);
 308     }
 309     if (duration && readers) {
 310         rcu_qtest(argv[0], duration, readers);
 311         return 0;
 312     }
 313
 314     usage(argc, argv);
 315     return -1;
 316 }