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 long long n_reads = 0LL; 39 long long n_updates = 0LL; 40 long long n_reclaims = 0LL; 41 long long n_nodes_removed = 0LL; 42 long long n_nodes = 0LL; 43 int g_test_in_charge = 0; 44 45 int nthreadsrunning; 46 47 char argsbuf[64]; 48 49 #define GOFLAG_INIT 0 50 #define GOFLAG_RUN 1 51 #define GOFLAG_STOP 2 52 53 static volatile int goflag = GOFLAG_INIT; 54 55 #define RCU_READ_RUN 1000 56 #define RCU_UPDATE_RUN 10 57 #define NR_THREADS 100 58 #define RCU_Q_LEN 100 59 60 static QemuThread threads[NR_THREADS]; 61 static struct rcu_reader_data *data[NR_THREADS]; 62 static int n_threads; 63 64 static int select_random_el(int max) 65 { 66 return (rand() % max); 67 } 68 69 70 static void create_thread(void *(*func)(void *)) 71 { 72 if (n_threads >= NR_THREADS) { 73 fprintf(stderr, "Thread limit of %d exceeded!\n", NR_THREADS); 74 exit(-1); 75 } 76 qemu_thread_create(&threads[n_threads], "test", func, &data[n_threads], 77 QEMU_THREAD_JOINABLE); 78 n_threads++; 79 } 80 81 static void wait_all_threads(void) 82 { 83 int i; 84 85 for (i = 0; i < n_threads; i++) { 86 qemu_thread_join(&threads[i]); 87 } 88 n_threads = 0; 89 } 90 91 92 struct list_element { 93 QLIST_ENTRY(list_element) entry; 94 struct rcu_head rcu; 95 long long val; 96 }; 97 98 static void reclaim_list_el(struct rcu_head *prcu) 99 { 100 struct list_element *el = container_of(prcu, struct list_element, rcu); 101 g_free(el); 102 atomic_add(&n_reclaims, 1); 103 } 104 105 static QLIST_HEAD(q_list_head, list_element) Q_list_head; 106 107 static void *rcu_q_reader(void *arg) 108 { 109 long long j, n_reads_local = 0; 110 struct list_element *el; 111 112 *(struct rcu_reader_data **)arg = &rcu_reader; 113 atomic_inc(&nthreadsrunning); 114 while (goflag == GOFLAG_INIT) { 115 g_usleep(1000); 116 } 117 118 while (goflag == GOFLAG_RUN) { 119 rcu_read_lock(); 120 QLIST_FOREACH_RCU(el, &Q_list_head, entry) { 121 j = atomic_read(&el->val); 122 (void)j; 123 n_reads_local++; 124 if (goflag == GOFLAG_STOP) { 125 break; 126 } 127 } 128 rcu_read_unlock(); 129 130 g_usleep(100); 131 } 132 atomic_add(&n_reads, n_reads_local); 133 return NULL; 134 } 135 136 137 static void *rcu_q_updater(void *arg) 138 { 139 int j, target_el; 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 atomic_add(&n_nodes, 1); 174 prev_el->val = atomic_read(&n_nodes); 175 QLIST_INSERT_BEFORE_RCU(el, prev_el, entry); 176 break; 177 } 178 } 179 180 n_updates_local += 2; 181 synchronize_rcu(); 182 } 183 synchronize_rcu(); 184 atomic_add(&n_updates, n_updates_local); 185 atomic_add(&n_nodes_removed, n_removed_local); 186 return NULL; 187 } 188 189 static void rcu_qtest_init(void) 190 { 191 struct list_element *new_el; 192 int i; 193 nthreadsrunning = 0; 194 srand(time(0)); 195 for (i = 0; i < RCU_Q_LEN; i++) { 196 new_el = g_new(struct list_element, 1); 197 new_el->val = i; 198 QLIST_INSERT_HEAD_RCU(&Q_list_head, new_el, entry); 199 } 200 atomic_add(&n_nodes, RCU_Q_LEN); 201 } 202 203 static void rcu_qtest_run(int duration, int nreaders) 204 { 205 int nthreads = nreaders + 1; 206 while (atomic_read(&nthreadsrunning) < nthreads) { 207 g_usleep(1000); 208 } 209 210 goflag = GOFLAG_RUN; 211 sleep(duration); 212 goflag = GOFLAG_STOP; 213 wait_all_threads(); 214 } 215 216 217 static void rcu_qtest(const char *test, int duration, int nreaders) 218 { 219 int i; 220 long long n_removed_local = 0; 221 222 struct list_element *el, *prev_el; 223 224 rcu_qtest_init(); 225 for (i = 0; i < nreaders; i++) { 226 create_thread(rcu_q_reader); 227 } 228 create_thread(rcu_q_updater); 229 rcu_qtest_run(duration, nreaders); 230 231 QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) { 232 QLIST_REMOVE_RCU(prev_el, entry); 233 call_rcu1(&prev_el->rcu, reclaim_list_el); 234 n_removed_local++; 235 } 236 atomic_add(&n_nodes_removed, n_removed_local); 237 synchronize_rcu(); 238 while (n_nodes_removed > n_reclaims) { 239 g_usleep(100); 240 synchronize_rcu(); 241 } 242 if (g_test_in_charge) { 243 g_assert_cmpint(n_nodes_removed, ==, n_reclaims); 244 } else { 245 printf("%s: %d readers; 1 updater; nodes read: " \ 246 "%lld, nodes removed: %lld; nodes reclaimed: %lld\n", 247 test, nthreadsrunning - 1, n_reads, n_nodes_removed, n_reclaims); 248 exit(0); 249 } 250 } 251 252 static void usage(int argc, char *argv[]) 253 { 254 fprintf(stderr, "Usage: %s duration nreaders\n", argv[0]); 255 exit(-1); 256 } 257 258 static int gtest_seconds; 259 260 static void gtest_rcuq_one(void) 261 { 262 rcu_qtest("rcuqtest", gtest_seconds / 4, 1); 263 } 264 265 static void gtest_rcuq_few(void) 266 { 267 rcu_qtest("rcuqtest", gtest_seconds / 4, 5); 268 } 269 270 static void gtest_rcuq_many(void) 271 { 272 rcu_qtest("rcuqtest", gtest_seconds / 2, 20); 273 } 274 275 276 int main(int argc, char *argv[]) 277 { 278 int duration = 0, readers = 0; 279 280 if (argc >= 2) { 281 if (argv[1][0] == '-') { 282 g_test_init(&argc, &argv, NULL); 283 if (g_test_quick()) { 284 gtest_seconds = 4; 285 } else { 286 gtest_seconds = 20; 287 } 288 g_test_add_func("/rcu/qlist/single-threaded", gtest_rcuq_one); 289 g_test_add_func("/rcu/qlist/short-few", gtest_rcuq_few); 290 g_test_add_func("/rcu/qlist/long-many", gtest_rcuq_many); 291 g_test_in_charge = 1; 292 return g_test_run(); 293 } 294 duration = strtoul(argv[1], NULL, 0); 295 } 296 if (argc >= 3) { 297 readers = strtoul(argv[2], NULL, 0); 298 } 299 if (duration && readers) { 300 rcu_qtest(argv[0], duration, readers); 301 return 0; 302 } 303 304 usage(argc, argv); 305 return -1; 306 } 307