| 1 | /* |
| 2 | * read/write() engine that uses syslet to be async |
| 3 | * |
| 4 | */ |
| 5 | #include <stdio.h> |
| 6 | #include <stdlib.h> |
| 7 | #include <unistd.h> |
| 8 | #include <errno.h> |
| 9 | #include <assert.h> |
| 10 | |
| 11 | #include "../fio.h" |
| 12 | #include "../os.h" |
| 13 | |
| 14 | #ifdef FIO_HAVE_SYSLET |
| 15 | |
| 16 | struct syslet_data { |
| 17 | struct io_u **events; |
| 18 | unsigned int nr_events; |
| 19 | |
| 20 | struct async_head_user ahu; |
| 21 | struct syslet_uatom **ring; |
| 22 | |
| 23 | struct syslet_uatom *head, *tail; |
| 24 | }; |
| 25 | |
| 26 | static void fio_syslet_complete_atom(struct thread_data *td, |
| 27 | struct syslet_uatom *atom) |
| 28 | { |
| 29 | struct syslet_data *sd = td->io_ops->data; |
| 30 | struct syslet_uatom *last; |
| 31 | struct io_u *io_u; |
| 32 | |
| 33 | /* |
| 34 | * complete from the beginning of the sequence up to (and |
| 35 | * including) this atom |
| 36 | */ |
| 37 | last = atom; |
| 38 | io_u = atom->private; |
| 39 | atom = io_u->req.head; |
| 40 | |
| 41 | /* |
| 42 | * now complete in right order |
| 43 | */ |
| 44 | do { |
| 45 | long ret; |
| 46 | |
| 47 | io_u = atom->private; |
| 48 | ret = *atom->ret_ptr; |
| 49 | if (ret > 0) |
| 50 | io_u->resid = io_u->xfer_buflen - ret; |
| 51 | else if (ret < 0) |
| 52 | io_u->error = ret; |
| 53 | |
| 54 | assert(sd->nr_events < td->iodepth); |
| 55 | sd->events[sd->nr_events++] = io_u; |
| 56 | |
| 57 | if (atom == last) |
| 58 | break; |
| 59 | |
| 60 | atom = atom->next; |
| 61 | } while (1); |
| 62 | |
| 63 | assert(!last->next); |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * Inspect the ring to see if we have completed events |
| 68 | */ |
| 69 | static void fio_syslet_complete(struct thread_data *td) |
| 70 | { |
| 71 | struct syslet_data *sd = td->io_ops->data; |
| 72 | |
| 73 | do { |
| 74 | struct syslet_uatom *atom; |
| 75 | |
| 76 | atom = sd->ring[sd->ahu.user_ring_idx]; |
| 77 | if (!atom) |
| 78 | break; |
| 79 | |
| 80 | sd->ring[sd->ahu.user_ring_idx] = NULL; |
| 81 | if (++sd->ahu.user_ring_idx == td->iodepth) |
| 82 | sd->ahu.user_ring_idx = 0; |
| 83 | |
| 84 | fio_syslet_complete_atom(td, atom); |
| 85 | } while (1); |
| 86 | } |
| 87 | |
| 88 | static int fio_syslet_getevents(struct thread_data *td, int min, |
| 89 | int fio_unused max, |
| 90 | struct timespec fio_unused *t) |
| 91 | { |
| 92 | struct syslet_data *sd = td->io_ops->data; |
| 93 | long ret; |
| 94 | |
| 95 | do { |
| 96 | fio_syslet_complete(td); |
| 97 | |
| 98 | /* |
| 99 | * do we have enough immediate completions? |
| 100 | */ |
| 101 | if (sd->nr_events >= (unsigned int) min) |
| 102 | break; |
| 103 | |
| 104 | /* |
| 105 | * OK, we need to wait for some events... |
| 106 | */ |
| 107 | ret = async_wait(1, sd->ahu.user_ring_idx, &sd->ahu); |
| 108 | if (ret < 0) |
| 109 | return -errno; |
| 110 | } while (1); |
| 111 | |
| 112 | ret = sd->nr_events; |
| 113 | sd->nr_events = 0; |
| 114 | return ret; |
| 115 | } |
| 116 | |
| 117 | static struct io_u *fio_syslet_event(struct thread_data *td, int event) |
| 118 | { |
| 119 | struct syslet_data *sd = td->io_ops->data; |
| 120 | |
| 121 | return sd->events[event]; |
| 122 | } |
| 123 | |
| 124 | static void init_atom(struct syslet_uatom *atom, int nr, void *arg0, |
| 125 | void *arg1, void *arg2, void *arg3, void *ret_ptr, |
| 126 | unsigned long flags, void *priv) |
| 127 | { |
| 128 | atom->flags = flags; |
| 129 | atom->nr = nr; |
| 130 | atom->ret_ptr = ret_ptr; |
| 131 | atom->next = NULL; |
| 132 | atom->arg_ptr[0] = arg0; |
| 133 | atom->arg_ptr[1] = arg1; |
| 134 | atom->arg_ptr[2] = arg2; |
| 135 | atom->arg_ptr[3] = arg3; |
| 136 | atom->arg_ptr[4] = atom->arg_ptr[5] = NULL; |
| 137 | atom->private = priv; |
| 138 | } |
| 139 | |
| 140 | /* |
| 141 | * Use seek atom for sync |
| 142 | */ |
| 143 | static void fio_syslet_prep_sync(struct io_u *io_u, struct fio_file *f) |
| 144 | { |
| 145 | init_atom(&io_u->req.atom, __NR_fsync, &f->fd, NULL, NULL, NULL, |
| 146 | &io_u->req.ret, 0, io_u); |
| 147 | } |
| 148 | |
| 149 | static void fio_syslet_prep_rw(struct io_u *io_u, struct fio_file *f) |
| 150 | { |
| 151 | int nr; |
| 152 | |
| 153 | /* |
| 154 | * prepare rw |
| 155 | */ |
| 156 | if (io_u->ddir == DDIR_READ) |
| 157 | nr = __NR_pread64; |
| 158 | else |
| 159 | nr = __NR_pwrite64; |
| 160 | |
| 161 | init_atom(&io_u->req.atom, nr, &f->fd, &io_u->xfer_buf, |
| 162 | &io_u->xfer_buflen, &io_u->offset, &io_u->req.ret, 0, io_u); |
| 163 | } |
| 164 | |
| 165 | static int fio_syslet_prep(struct thread_data fio_unused *td, struct io_u *io_u) |
| 166 | { |
| 167 | struct fio_file *f = io_u->file; |
| 168 | |
| 169 | if (io_u->ddir == DDIR_SYNC) |
| 170 | fio_syslet_prep_sync(io_u, f); |
| 171 | else |
| 172 | fio_syslet_prep_rw(io_u, f); |
| 173 | |
| 174 | return 0; |
| 175 | } |
| 176 | |
| 177 | static void cachemiss_thread_start(void) |
| 178 | { |
| 179 | while (1) |
| 180 | async_thread(NULL, NULL); |
| 181 | } |
| 182 | |
| 183 | #define THREAD_STACK_SIZE (16384) |
| 184 | |
| 185 | static unsigned long thread_stack_alloc() |
| 186 | { |
| 187 | return (unsigned long) malloc(THREAD_STACK_SIZE) + THREAD_STACK_SIZE; |
| 188 | } |
| 189 | |
| 190 | static int fio_syslet_commit(struct thread_data *td) |
| 191 | { |
| 192 | struct syslet_data *sd = td->io_ops->data; |
| 193 | struct syslet_uatom *done; |
| 194 | |
| 195 | if (!sd->head) |
| 196 | return 0; |
| 197 | |
| 198 | assert(!sd->tail->next); |
| 199 | |
| 200 | if (!sd->ahu.new_thread_stack) |
| 201 | sd->ahu.new_thread_stack = thread_stack_alloc(); |
| 202 | |
| 203 | /* |
| 204 | * On sync completion, the atom is returned. So on NULL return |
| 205 | * it's queued asynchronously. |
| 206 | */ |
| 207 | done = async_exec(sd->head, &sd->ahu); |
| 208 | |
| 209 | sd->head = sd->tail = NULL; |
| 210 | |
| 211 | if (done) |
| 212 | fio_syslet_complete_atom(td, done); |
| 213 | |
| 214 | return 0; |
| 215 | } |
| 216 | |
| 217 | static int fio_syslet_queue(struct thread_data *td, struct io_u *io_u) |
| 218 | { |
| 219 | struct syslet_data *sd = td->io_ops->data; |
| 220 | |
| 221 | if (sd->tail) { |
| 222 | sd->tail->next = &io_u->req.atom; |
| 223 | sd->tail = &io_u->req.atom; |
| 224 | } else |
| 225 | sd->head = sd->tail = &io_u->req.atom; |
| 226 | |
| 227 | io_u->req.head = sd->head; |
| 228 | return FIO_Q_QUEUED; |
| 229 | } |
| 230 | |
| 231 | static int async_head_init(struct syslet_data *sd, unsigned int depth) |
| 232 | { |
| 233 | unsigned long ring_size; |
| 234 | |
| 235 | memset(&sd->ahu, 0, sizeof(struct async_head_user)); |
| 236 | |
| 237 | ring_size = sizeof(struct syslet_uatom *) * depth; |
| 238 | sd->ring = malloc(ring_size); |
| 239 | memset(sd->ring, 0, ring_size); |
| 240 | |
| 241 | sd->ahu.user_ring_idx = 0; |
| 242 | sd->ahu.completion_ring = sd->ring; |
| 243 | sd->ahu.ring_size_bytes = ring_size; |
| 244 | sd->ahu.head_stack = thread_stack_alloc(); |
| 245 | sd->ahu.head_eip = (unsigned long) cachemiss_thread_start; |
| 246 | sd->ahu.new_thread_eip = (unsigned long) cachemiss_thread_start; |
| 247 | |
| 248 | return 0; |
| 249 | } |
| 250 | |
| 251 | static void async_head_exit(struct syslet_data *sd) |
| 252 | { |
| 253 | free(sd->ring); |
| 254 | } |
| 255 | |
| 256 | static void fio_syslet_cleanup(struct thread_data *td) |
| 257 | { |
| 258 | struct syslet_data *sd = td->io_ops->data; |
| 259 | |
| 260 | if (sd) { |
| 261 | async_head_exit(sd); |
| 262 | free(sd->events); |
| 263 | free(sd); |
| 264 | td->io_ops->data = NULL; |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | static int fio_syslet_init(struct thread_data *td) |
| 269 | { |
| 270 | struct syslet_data *sd; |
| 271 | |
| 272 | |
| 273 | sd = malloc(sizeof(*sd)); |
| 274 | memset(sd, 0, sizeof(*sd)); |
| 275 | sd->events = malloc(sizeof(struct io_u *) * td->iodepth); |
| 276 | memset(sd->events, 0, sizeof(struct io_u *) * td->iodepth); |
| 277 | |
| 278 | /* |
| 279 | * This will handily fail for kernels where syslet isn't available |
| 280 | */ |
| 281 | if (async_head_init(sd, td->iodepth)) { |
| 282 | free(sd->events); |
| 283 | free(sd); |
| 284 | return 1; |
| 285 | } |
| 286 | |
| 287 | td->io_ops->data = sd; |
| 288 | return 0; |
| 289 | } |
| 290 | |
| 291 | static struct ioengine_ops ioengine = { |
| 292 | .name = "syslet-rw", |
| 293 | .version = FIO_IOOPS_VERSION, |
| 294 | .init = fio_syslet_init, |
| 295 | .prep = fio_syslet_prep, |
| 296 | .queue = fio_syslet_queue, |
| 297 | .commit = fio_syslet_commit, |
| 298 | .getevents = fio_syslet_getevents, |
| 299 | .event = fio_syslet_event, |
| 300 | .cleanup = fio_syslet_cleanup, |
| 301 | }; |
| 302 | |
| 303 | #else /* FIO_HAVE_SYSLET */ |
| 304 | |
| 305 | /* |
| 306 | * When we have a proper configure system in place, we simply wont build |
| 307 | * and install this io engine. For now install a crippled version that |
| 308 | * just complains and fails to load. |
| 309 | */ |
| 310 | static int fio_syslet_init(struct thread_data fio_unused *td) |
| 311 | { |
| 312 | fprintf(stderr, "fio: syslet not available\n"); |
| 313 | return 1; |
| 314 | } |
| 315 | |
| 316 | static struct ioengine_ops ioengine = { |
| 317 | .name = "syslet-rw", |
| 318 | .version = FIO_IOOPS_VERSION, |
| 319 | .init = fio_syslet_init, |
| 320 | }; |
| 321 | |
| 322 | #endif /* FIO_HAVE_SYSLET */ |
| 323 | |
| 324 | static void fio_init fio_syslet_register(void) |
| 325 | { |
| 326 | register_ioengine(&ioengine); |
| 327 | } |
| 328 | |
| 329 | static void fio_exit fio_syslet_unregister(void) |
| 330 | { |
| 331 | unregister_ioengine(&ioengine); |
| 332 | } |