1 /* 2 * libaio engine 3 * 4 * IO engine using the Linux native aio interface. 5 * 6 */ 7 #include <stdio.h> 8 #include <stdlib.h> 9 #include <unistd.h> 10 #include <errno.h> 11 #include <assert.h> 12 #include <libaio.h> 13 14 #include "../fio.h" 15 16 static int fio_libaio_commit(struct thread_data *td); 17 18 struct libaio_data { 19 io_context_t aio_ctx; 20 struct io_event *aio_events; 21 struct iocb **iocbs; 22 struct io_u **io_us; 23 24 /* 25 * Basic ring buffer. 'head' is incremented in _queue(), and 26 * 'tail' is incremented in _commit(). We keep 'queued' so 27 * that we know if the ring is full or empty, when 28 * 'head' == 'tail'. 'entries' is the ring size, and 29 * 'is_pow2' is just an optimization to use AND instead of 30 * modulus to get the remainder on ring increment. 31 */ 32 int is_pow2; 33 unsigned int entries; 34 unsigned int queued; 35 unsigned int head; 36 unsigned int tail; 37 }; 38 39 struct libaio_options { 40 void *pad; 41 unsigned int userspace_reap; 42 }; 43 44 static struct fio_option options[] = { 45 { 46 .name = "userspace_reap", 47 .lname = "Libaio userspace reaping", 48 .type = FIO_OPT_STR_SET, 49 .off1 = offsetof(struct libaio_options, userspace_reap), 50 .help = "Use alternative user-space reap implementation", 51 .category = FIO_OPT_C_ENGINE, 52 .group = FIO_OPT_G_LIBAIO, 53 }, 54 { 55 .name = NULL, 56 }, 57 }; 58 59 static inline void ring_inc(struct libaio_data *ld, unsigned int *val, 60 unsigned int add) 61 { 62 if (ld->is_pow2) 63 *val = (*val + add) & (ld->entries - 1); 64 else 65 *val = (*val + add) % ld->entries; 66 } 67 68 static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u) 69 { 70 struct fio_file *f = io_u->file; 71 72 if (io_u->ddir == DDIR_READ) 73 io_prep_pread(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset); 74 else if (io_u->ddir == DDIR_WRITE) 75 io_prep_pwrite(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset); 76 else if (ddir_sync(io_u->ddir)) 77 io_prep_fsync(&io_u->iocb, f->fd); 78 79 return 0; 80 } 81 82 static struct io_u *fio_libaio_event(struct thread_data *td, int event) 83 { 84 struct libaio_data *ld = td->io_ops->data; 85 struct io_event *ev; 86 struct io_u *io_u; 87 88 ev = ld->aio_events + event; 89 io_u = container_of(ev->obj, struct io_u, iocb); 90 91 if (ev->res != io_u->xfer_buflen) { 92 if (ev->res > io_u->xfer_buflen) 93 io_u->error = -ev->res; 94 else 95 io_u->resid = io_u->xfer_buflen - ev->res; 96 } else 97 io_u->error = 0; 98 99 return io_u; 100 } 101 102 struct aio_ring { 103 unsigned id; /** kernel internal index number */ 104 unsigned nr; /** number of io_events */ 105 unsigned head; 106 unsigned tail; 107 108 unsigned magic; 109 unsigned compat_features; 110 unsigned incompat_features; 111 unsigned header_length; /** size of aio_ring */ 112 113 struct io_event events[0]; 114 }; 115 116 #define AIO_RING_MAGIC 0xa10a10a1 117 118 static int user_io_getevents(io_context_t aio_ctx, unsigned int max, 119 struct io_event *events) 120 { 121 long i = 0; 122 unsigned head; 123 struct aio_ring *ring = (struct aio_ring*) aio_ctx; 124 125 while (i < max) { 126 head = ring->head; 127 128 if (head == ring->tail) { 129 /* There are no more completions */ 130 break; 131 } else { 132 /* There is another completion to reap */ 133 events[i] = ring->events[head]; 134 read_barrier(); 135 ring->head = (head + 1) % ring->nr; 136 i++; 137 } 138 } 139 140 return i; 141 } 142 143 static int fio_libaio_getevents(struct thread_data *td, unsigned int min, 144 unsigned int max, const struct timespec *t) 145 { 146 struct libaio_data *ld = td->io_ops->data; 147 struct libaio_options *o = td->eo; 148 unsigned actual_min = td->o.iodepth_batch_complete == 0 ? 0 : min; 149 struct timespec __lt, *lt = NULL; 150 int r, events = 0; 151 152 if (t) { 153 __lt = *t; 154 lt = &__lt; 155 } 156 157 do { 158 if (o->userspace_reap == 1 159 && actual_min == 0 160 && ((struct aio_ring *)(ld->aio_ctx))->magic 161 == AIO_RING_MAGIC) { 162 r = user_io_getevents(ld->aio_ctx, max, 163 ld->aio_events + events); 164 } else { 165 r = io_getevents(ld->aio_ctx, actual_min, 166 max, ld->aio_events + events, lt); 167 } 168 if (r > 0) 169 events += r; 170 else if ((min && r == 0) || r == -EAGAIN) { 171 fio_libaio_commit(td); 172 usleep(100); 173 } else if (r != -EINTR) 174 break; 175 } while (events < min); 176 177 return r < 0 ? r : events; 178 } 179 180 static int fio_libaio_queue(struct thread_data *td, struct io_u *io_u) 181 { 182 struct libaio_data *ld = td->io_ops->data; 183 184 fio_ro_check(td, io_u); 185 186 if (ld->queued == td->o.iodepth) 187 return FIO_Q_BUSY; 188 189 /* 190 * fsync is tricky, since it can fail and we need to do it 191 * serialized with other io. the reason is that linux doesn't 192 * support aio fsync yet. So return busy for the case where we 193 * have pending io, to let fio complete those first. 194 */ 195 if (ddir_sync(io_u->ddir)) { 196 if (ld->queued) 197 return FIO_Q_BUSY; 198 199 do_io_u_sync(td, io_u); 200 return FIO_Q_COMPLETED; 201 } 202 203 if (io_u->ddir == DDIR_TRIM) { 204 if (ld->queued) 205 return FIO_Q_BUSY; 206 207 do_io_u_trim(td, io_u); 208 return FIO_Q_COMPLETED; 209 } 210 211 ld->iocbs[ld->head] = &io_u->iocb; 212 ld->io_us[ld->head] = io_u; 213 ring_inc(ld, &ld->head, 1); 214 ld->queued++; 215 return FIO_Q_QUEUED; 216 } 217 218 static void fio_libaio_queued(struct thread_data *td, struct io_u **io_us, 219 unsigned int nr) 220 { 221 struct timeval now; 222 unsigned int i; 223 224 if (!fio_fill_issue_time(td)) 225 return; 226 227 fio_gettime(&now, NULL); 228 229 for (i = 0; i < nr; i++) { 230 struct io_u *io_u = io_us[i]; 231 232 memcpy(&io_u->issue_time, &now, sizeof(now)); 233 io_u_queued(td, io_u); 234 } 235 } 236 237 static int fio_libaio_commit(struct thread_data *td) 238 { 239 struct libaio_data *ld = td->io_ops->data; 240 struct iocb **iocbs; 241 struct io_u **io_us; 242 struct timeval tv; 243 int ret, wait_start = 0; 244 245 if (!ld->queued) 246 return 0; 247 248 do { 249 long nr = ld->queued; 250 251 nr = min((unsigned int) nr, ld->entries - ld->tail); 252 io_us = ld->io_us + ld->tail; 253 iocbs = ld->iocbs + ld->tail; 254 255 ret = io_submit(ld->aio_ctx, nr, iocbs); 256 if (ret > 0) { 257 fio_libaio_queued(td, io_us, ret); 258 io_u_mark_submit(td, ret); 259 260 ld->queued -= ret; 261 ring_inc(ld, &ld->tail, ret); 262 ret = 0; 263 wait_start = 0; 264 } else if (ret == -EINTR || !ret) { 265 if (!ret) 266 io_u_mark_submit(td, ret); 267 wait_start = 0; 268 continue; 269 } else if (ret == -EAGAIN) { 270 /* 271 * If we get EAGAIN, we should break out without 272 * error and let the upper layer reap some 273 * events for us. If we have no queued IO, we 274 * must loop here. If we loop for more than 30s, 275 * just error out, something must be buggy in the 276 * IO path. 277 */ 278 if (ld->queued) { 279 ret = 0; 280 break; 281 } 282 if (!wait_start) { 283 fio_gettime(&tv, NULL); 284 wait_start = 1; 285 } else if (mtime_since_now(&tv) > 30000) { 286 log_err("fio: aio appears to be stalled, giving up\n"); 287 break; 288 } 289 usleep(1); 290 continue; 291 } else if (ret == -ENOMEM) { 292 /* 293 * If we get -ENOMEM, reap events if we can. If 294 * we cannot, treat it as a fatal event since there's 295 * nothing we can do about it. 296 */ 297 if (ld->queued) 298 ret = 0; 299 break; 300 } else 301 break; 302 } while (ld->queued); 303 304 return ret; 305 } 306 307 static int fio_libaio_cancel(struct thread_data *td, struct io_u *io_u) 308 { 309 struct libaio_data *ld = td->io_ops->data; 310 311 return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events); 312 } 313 314 static void fio_libaio_cleanup(struct thread_data *td) 315 { 316 struct libaio_data *ld = td->io_ops->data; 317 318 if (ld) { 319 io_destroy(ld->aio_ctx); 320 free(ld->aio_events); 321 free(ld->iocbs); 322 free(ld->io_us); 323 free(ld); 324 } 325 } 326 327 static int fio_libaio_init(struct thread_data *td) 328 { 329 struct libaio_options *o = td->eo; 330 struct libaio_data *ld; 331 int err = 0; 332 333 ld = calloc(1, sizeof(*ld)); 334 335 /* 336 * First try passing in 0 for queue depth, since we don't 337 * care about the user ring. If that fails, the kernel is too old 338 * and we need the right depth. 339 */ 340 if (!o->userspace_reap) 341 err = io_queue_init(INT_MAX, &ld->aio_ctx); 342 if (o->userspace_reap || err == -EINVAL) 343 err = io_queue_init(td->o.iodepth, &ld->aio_ctx); 344 if (err) { 345 td_verror(td, -err, "io_queue_init"); 346 log_err("fio: check /proc/sys/fs/aio-max-nr\n"); 347 free(ld); 348 return 1; 349 } 350 351 ld->entries = td->o.iodepth; 352 ld->is_pow2 = is_power_of_2(ld->entries); 353 ld->aio_events = calloc(ld->entries, sizeof(struct io_event)); 354 ld->iocbs = calloc(ld->entries, sizeof(struct iocb *)); 355 ld->io_us = calloc(ld->entries, sizeof(struct io_u *)); 356 357 td->io_ops->data = ld; 358 return 0; 359 } 360 361 static struct ioengine_ops ioengine = { 362 .name = "libaio", 363 .version = FIO_IOOPS_VERSION, 364 .init = fio_libaio_init, 365 .prep = fio_libaio_prep, 366 .queue = fio_libaio_queue, 367 .commit = fio_libaio_commit, 368 .cancel = fio_libaio_cancel, 369 .getevents = fio_libaio_getevents, 370 .event = fio_libaio_event, 371 .cleanup = fio_libaio_cleanup, 372 .open_file = generic_open_file, 373 .close_file = generic_close_file, 374 .get_file_size = generic_get_file_size, 375 .options = options, 376 .option_struct_size = sizeof(struct libaio_options), 377 }; 378 379 static void fio_init fio_libaio_register(void) 380 { 381 register_ioengine(&ioengine); 382 } 383 384 static void fio_exit fio_libaio_unregister(void) 385 { 386 unregister_ioengine(&ioengine); 387 } 388
