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 *(struct rcu_reader_data **)arg = &rcu_reader; 112 atomic_inc(&nthreadsrunning); 113 while (goflag == GOFLAG_INIT) { 114 g_usleep(1000); 115 } 116 117 while (goflag == GOFLAG_RUN) { 118 rcu_read_lock(); 119 QLIST_FOREACH_RCU(el, &Q_list_head, entry) { 120 n_reads_local++; 121 if (goflag == GOFLAG_STOP) { 122 break; 123 } 124 } 125 rcu_read_unlock(); 126 127 g_usleep(100); 128 } 129 qemu_mutex_lock(&counts_mutex); 130 n_reads += n_reads_local; 131 qemu_mutex_unlock(&counts_mutex); 132 return NULL; 133 } 134 135 136 static void *rcu_q_updater(void *arg) 137 { 138 int j, target_el; 139 long long n_nodes_local = 0; 140 long long n_updates_local = 0; 141 long long n_removed_local = 0; 142 struct list_element *el, *prev_el; 143 144 *(struct rcu_reader_data **)arg = &rcu_reader; 145 atomic_inc(&nthreadsrunning); 146 while (goflag == GOFLAG_INIT) { 147 g_usleep(1000); 148 } 149 150 while (goflag == GOFLAG_RUN) { 151 target_el = select_random_el(RCU_Q_LEN); 152 j = 0; 153 /* FOREACH_RCU could work here but let's use both macros */ 154 QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) { 155 j++; 156 if (target_el == j) { 157 QLIST_REMOVE_RCU(prev_el, entry); 158 /* may be more than one updater in the future */ 159 call_rcu1(&prev_el->rcu, reclaim_list_el); 160 n_removed_local++; 161 break; 162 } 163 } 164 if (goflag == GOFLAG_STOP) { 165 break; 166 } 167 target_el = select_random_el(RCU_Q_LEN); 168 j = 0; 169 QLIST_FOREACH_RCU(el, &Q_list_head, entry) { 170 j++; 171 if (target_el == j) { 172 prev_el = g_new(struct list_element, 1); 173 n_nodes += n_nodes_local; 174 QLIST_INSERT_BEFORE_RCU(el, prev_el, entry); 175 break; 176 } 177 } 178 179 n_updates_local += 2; 180 synchronize_rcu(); 181 } 182 synchronize_rcu(); 183 qemu_mutex_lock(&counts_mutex); 184 n_nodes += n_nodes_local; 185 n_updates += n_updates_local; 186 n_nodes_removed += n_removed_local; 187 qemu_mutex_unlock(&counts_mutex); 188 return NULL; 189 } 190 191 static void rcu_qtest_init(void) 192 { 193 struct list_element *new_el; 194 int i; 195 nthreadsrunning = 0; 196 srand(time(0)); 197 for (i = 0; i < RCU_Q_LEN; i++) { 198 new_el = g_new(struct list_element, 1); 199 QLIST_INSERT_HEAD_RCU(&Q_list_head, new_el, entry); 200 } 201 qemu_mutex_lock(&counts_mutex); 202 n_nodes += RCU_Q_LEN; 203 qemu_mutex_unlock(&counts_mutex); 204 } 205 206 static void rcu_qtest_run(int duration, int nreaders) 207 { 208 int nthreads = nreaders + 1; 209 while (atomic_read(&nthreadsrunning) < nthreads) { 210 g_usleep(1000); 211 } 212 213 goflag = GOFLAG_RUN; 214 sleep(duration); 215 goflag = GOFLAG_STOP; 216 wait_all_threads(); 217 } 218 219 220 static void rcu_qtest(const char *test, int duration, int nreaders) 221 { 222 int i; 223 long long n_removed_local = 0; 224 225 struct list_element *el, *prev_el; 226 227 rcu_qtest_init(); 228 for (i = 0; i < nreaders; i++) { 229 create_thread(rcu_q_reader); 230 } 231 create_thread(rcu_q_updater); 232 rcu_qtest_run(duration, nreaders); 233 234 QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) { 235 QLIST_REMOVE_RCU(prev_el, entry); 236 call_rcu1(&prev_el->rcu, reclaim_list_el); 237 n_removed_local++; 238 } 239 qemu_mutex_lock(&counts_mutex); 240 n_nodes_removed += n_removed_local; 241 qemu_mutex_unlock(&counts_mutex); 242 synchronize_rcu(); 243 while (n_nodes_removed > n_reclaims) { 244 g_usleep(100); 245 synchronize_rcu(); 246 } 247 if (g_test_in_charge) { 248 g_assert_cmpint(n_nodes_removed, ==, n_reclaims); 249 } else { 250 printf("%s: %d readers; 1 updater; nodes read: " \ 251 "%lld, nodes removed: %lld; nodes reclaimed: %lld\n", 252 test, nthreadsrunning - 1, n_reads, n_nodes_removed, n_reclaims); 253 exit(0); 254 } 255 } 256 257 static void usage(int argc, char *argv[]) 258 { 259 fprintf(stderr, "Usage: %s duration nreaders\n", argv[0]); 260 exit(-1); 261 } 262 263 static int gtest_seconds; 264 265 static void gtest_rcuq_one(void) 266 { 267 rcu_qtest("rcuqtest", gtest_seconds / 4, 1); 268 } 269 270 static void gtest_rcuq_few(void) 271 { 272 rcu_qtest("rcuqtest", gtest_seconds / 4, 5); 273 } 274 275 static void gtest_rcuq_many(void) 276 { 277 rcu_qtest("rcuqtest", gtest_seconds / 2, 20); 278 } 279 280 281 int main(int argc, char *argv[]) 282 { 283 int duration = 0, readers = 0; 284 285 qemu_mutex_init(&counts_mutex); 286 if (argc >= 2) { 287 if (argv[1][0] == '-') { 288 g_test_init(&argc, &argv, NULL); 289 if (g_test_quick()) { 290 gtest_seconds = 4; 291 } else { 292 gtest_seconds = 20; 293 } 294 g_test_add_func("/rcu/qlist/single-threaded", gtest_rcuq_one); 295 g_test_add_func("/rcu/qlist/short-few", gtest_rcuq_few); 296 g_test_add_func("/rcu/qlist/long-many", gtest_rcuq_many); 297 g_test_in_charge = 1; 298 return g_test_run(); 299 } 300 duration = strtoul(argv[1], NULL, 0); 301 } 302 if (argc >= 3) { 303 readers = strtoul(argv[2], NULL, 0); 304 } 305 if (duration && readers) { 306 rcu_qtest(argv[0], duration, readers); 307 return 0; 308 } 309 310 usage(argc, argv); 311 return -1; 312 } 313