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 } 317