| 1 | /* |
| 2 | * syslet engine |
| 3 | * |
| 4 | * IO engine that does regular pread(2)/pwrite(2) to transfer data, but |
| 5 | * with syslets to make the execution async. |
| 6 | * |
| 7 | */ |
| 8 | #include <stdio.h> |
| 9 | #include <stdlib.h> |
| 10 | #include <unistd.h> |
| 11 | #include <errno.h> |
| 12 | #include <assert.h> |
| 13 | #include <malloc.h> |
| 14 | #include <asm/unistd.h> |
| 15 | |
| 16 | #include "../fio.h" |
| 17 | #include "../lib/fls.h" |
| 18 | |
| 19 | #ifdef FIO_HAVE_SYSLET |
| 20 | |
| 21 | #ifdef __NR_pread64 |
| 22 | #define __NR_fio_pread __NR_pread64 |
| 23 | #define __NR_fio_pwrite __NR_pwrite64 |
| 24 | #else |
| 25 | #define __NR_fio_pread __NR_pread |
| 26 | #define __NR_fio_pwrite __NR_pwrite |
| 27 | #endif |
| 28 | |
| 29 | struct syslet_data { |
| 30 | struct io_u **events; |
| 31 | unsigned int nr_events; |
| 32 | |
| 33 | struct syslet_ring *ring; |
| 34 | unsigned int ring_mask; |
| 35 | void *stack; |
| 36 | }; |
| 37 | |
| 38 | static void fio_syslet_add_event(struct thread_data *td, struct io_u *io_u) |
| 39 | { |
| 40 | struct syslet_data *sd = td->io_ops->data; |
| 41 | |
| 42 | assert(sd->nr_events < td->o.iodepth); |
| 43 | sd->events[sd->nr_events++] = io_u; |
| 44 | } |
| 45 | |
| 46 | static void fio_syslet_add_events(struct thread_data *td, unsigned int nr) |
| 47 | { |
| 48 | struct syslet_data *sd = td->io_ops->data; |
| 49 | unsigned int i, uidx; |
| 50 | |
| 51 | uidx = sd->ring->user_tail; |
| 52 | read_barrier(); |
| 53 | |
| 54 | for (i = 0; i < nr; i++) { |
| 55 | unsigned int idx = (i + uidx) & sd->ring_mask; |
| 56 | struct syslet_completion *comp = &sd->ring->comp[idx]; |
| 57 | struct io_u *io_u = (struct io_u *) (long) comp->caller_data; |
| 58 | long ret; |
| 59 | |
| 60 | ret = comp->status; |
| 61 | if (ret <= 0) { |
| 62 | io_u->resid = io_u->xfer_buflen; |
| 63 | io_u->error = -ret; |
| 64 | } else { |
| 65 | io_u->resid = io_u->xfer_buflen - ret; |
| 66 | io_u->error = 0; |
| 67 | } |
| 68 | |
| 69 | fio_syslet_add_event(td, io_u); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | static void fio_syslet_wait_for_events(struct thread_data *td) |
| 74 | { |
| 75 | struct syslet_data *sd = td->io_ops->data; |
| 76 | struct syslet_ring *ring = sd->ring; |
| 77 | |
| 78 | do { |
| 79 | unsigned int kh = ring->kernel_head; |
| 80 | int ret; |
| 81 | |
| 82 | /* |
| 83 | * first reap events that are already completed |
| 84 | */ |
| 85 | if (ring->user_tail != kh) { |
| 86 | unsigned int nr = kh - ring->user_tail; |
| 87 | |
| 88 | fio_syslet_add_events(td, nr); |
| 89 | ring->user_tail = kh; |
| 90 | break; |
| 91 | } |
| 92 | |
| 93 | /* |
| 94 | * block waiting for at least one event |
| 95 | */ |
| 96 | ret = syscall(__NR_syslet_ring_wait, ring, ring->user_tail); |
| 97 | assert(!ret); |
| 98 | } while (1); |
| 99 | } |
| 100 | |
| 101 | static int fio_syslet_getevents(struct thread_data *td, unsigned int min, |
| 102 | unsigned int fio_unused max, |
| 103 | struct timespec fio_unused *t) |
| 104 | { |
| 105 | struct syslet_data *sd = td->io_ops->data; |
| 106 | long ret; |
| 107 | |
| 108 | /* |
| 109 | * While we have less events than requested, block waiting for them |
| 110 | * (if we have to, there may already be more completed events ready |
| 111 | * for us - see fio_syslet_wait_for_events() |
| 112 | */ |
| 113 | while (sd->nr_events < min) |
| 114 | fio_syslet_wait_for_events(td); |
| 115 | |
| 116 | ret = sd->nr_events; |
| 117 | sd->nr_events = 0; |
| 118 | return ret; |
| 119 | } |
| 120 | |
| 121 | static struct io_u *fio_syslet_event(struct thread_data *td, int event) |
| 122 | { |
| 123 | struct syslet_data *sd = td->io_ops->data; |
| 124 | |
| 125 | return sd->events[event]; |
| 126 | } |
| 127 | |
| 128 | static void fio_syslet_prep_sync(struct fio_file *f, |
| 129 | struct indirect_registers *regs) |
| 130 | { |
| 131 | FILL_IN(*regs, __NR_fsync, (long) f->fd); |
| 132 | } |
| 133 | |
| 134 | static void fio_syslet_prep_datasync(struct fio_file *f, |
| 135 | struct indirect_registers *regs) |
| 136 | { |
| 137 | FILL_IN(*regs, __NR_fdatasync, (long) f->fd); |
| 138 | } |
| 139 | |
| 140 | static void fio_syslet_prep_rw(struct io_u *io_u, struct fio_file *f, |
| 141 | struct indirect_registers *regs) |
| 142 | { |
| 143 | long nr; |
| 144 | |
| 145 | /* |
| 146 | * prepare rw |
| 147 | */ |
| 148 | if (io_u->ddir == DDIR_READ) |
| 149 | nr = __NR_fio_pread; |
| 150 | else |
| 151 | nr = __NR_fio_pwrite; |
| 152 | |
| 153 | FILL_IN(*regs, nr, (long) f->fd, (long) io_u->xfer_buf, |
| 154 | (long) io_u->xfer_buflen, (long) io_u->offset); |
| 155 | } |
| 156 | |
| 157 | static void fio_syslet_prep(struct io_u *io_u, struct indirect_registers *regs) |
| 158 | { |
| 159 | struct fio_file *f = io_u->file; |
| 160 | |
| 161 | if (io_u->ddir == DDIR_SYNC) |
| 162 | fio_syslet_prep_sync(f, regs); |
| 163 | else if (io_u->ddir == DDIR_DATASYNC) |
| 164 | fio_syslet_prep_datasync(f, regs); |
| 165 | else |
| 166 | fio_syslet_prep_rw(io_u, f, regs); |
| 167 | } |
| 168 | |
| 169 | static void ret_func(void) |
| 170 | { |
| 171 | syscall(__NR_exit); |
| 172 | } |
| 173 | |
| 174 | static int fio_syslet_queue(struct thread_data *td, struct io_u *io_u) |
| 175 | { |
| 176 | struct syslet_data *sd = td->io_ops->data; |
| 177 | union indirect_params params; |
| 178 | struct indirect_registers regs; |
| 179 | int ret; |
| 180 | |
| 181 | fio_ro_check(td, io_u); |
| 182 | |
| 183 | memset(¶ms, 0, sizeof(params)); |
| 184 | fill_syslet_args(¶ms.syslet, sd->ring, (long)io_u, ret_func, sd->stack); |
| 185 | |
| 186 | fio_syslet_prep(io_u, ®s); |
| 187 | |
| 188 | ret = syscall(__NR_indirect, ®s, ¶ms, sizeof(params), 0); |
| 189 | if (ret == (int) io_u->xfer_buflen) { |
| 190 | /* |
| 191 | * completed sync, account. this also catches fsync(). |
| 192 | */ |
| 193 | return FIO_Q_COMPLETED; |
| 194 | } else if (ret < 0) { |
| 195 | /* |
| 196 | * queued for async execution |
| 197 | */ |
| 198 | if (errno == ESYSLETPENDING) |
| 199 | return FIO_Q_QUEUED; |
| 200 | } |
| 201 | |
| 202 | io_u->error = errno; |
| 203 | td_verror(td, io_u->error, "xfer"); |
| 204 | return FIO_Q_COMPLETED; |
| 205 | } |
| 206 | |
| 207 | static int check_syslet_support(struct syslet_data *sd) |
| 208 | { |
| 209 | union indirect_params params; |
| 210 | struct indirect_registers regs; |
| 211 | pid_t pid, my_pid = getpid(); |
| 212 | |
| 213 | memset(¶ms, 0, sizeof(params)); |
| 214 | fill_syslet_args(¶ms.syslet, sd->ring, 0, ret_func, sd->stack); |
| 215 | |
| 216 | FILL_IN(regs, __NR_getpid); |
| 217 | |
| 218 | pid = syscall(__NR_indirect, ®s, ¶ms, sizeof(params), 0); |
| 219 | if (pid == my_pid) |
| 220 | return 0; |
| 221 | |
| 222 | return 1; |
| 223 | } |
| 224 | |
| 225 | static void fio_syslet_cleanup(struct thread_data *td) |
| 226 | { |
| 227 | struct syslet_data *sd = td->io_ops->data; |
| 228 | |
| 229 | if (sd) { |
| 230 | free(sd->events); |
| 231 | free(sd->ring); |
| 232 | free(sd); |
| 233 | } |
| 234 | } |
| 235 | |
| 236 | static int fio_syslet_init(struct thread_data *td) |
| 237 | { |
| 238 | struct syslet_data *sd; |
| 239 | void *ring = NULL, *stack = NULL; |
| 240 | unsigned int ring_size, ring_nr; |
| 241 | |
| 242 | sd = malloc(sizeof(*sd)); |
| 243 | memset(sd, 0, sizeof(*sd)); |
| 244 | |
| 245 | sd->events = malloc(sizeof(struct io_u *) * td->o.iodepth); |
| 246 | memset(sd->events, 0, sizeof(struct io_u *) * td->o.iodepth); |
| 247 | |
| 248 | /* |
| 249 | * The ring needs to be a power-of-2, so round it up if we have to |
| 250 | */ |
| 251 | ring_nr = td->o.iodepth; |
| 252 | if (ring_nr & (ring_nr - 1)) |
| 253 | ring_nr = 1 << __fls(ring_nr); |
| 254 | |
| 255 | ring_size = sizeof(struct syslet_ring) + |
| 256 | ring_nr * sizeof(struct syslet_completion); |
| 257 | if (posix_memalign(&ring, sizeof(uint64_t), ring_size)) |
| 258 | goto err_mem; |
| 259 | if (posix_memalign(&stack, page_size, page_size)) |
| 260 | goto err_mem; |
| 261 | |
| 262 | sd->ring = ring; |
| 263 | sd->ring_mask = ring_nr - 1; |
| 264 | sd->stack = stack; |
| 265 | |
| 266 | memset(sd->ring, 0, ring_size); |
| 267 | sd->ring->elements = ring_nr; |
| 268 | |
| 269 | if (!check_syslet_support(sd)) { |
| 270 | td->io_ops->data = sd; |
| 271 | return 0; |
| 272 | } |
| 273 | |
| 274 | log_err("fio: syslets do not appear to work\n"); |
| 275 | err_mem: |
| 276 | free(sd->events); |
| 277 | if (ring) |
| 278 | free(ring); |
| 279 | if (stack) |
| 280 | free(stack); |
| 281 | free(sd); |
| 282 | return 1; |
| 283 | } |
| 284 | |
| 285 | static struct ioengine_ops ioengine = { |
| 286 | .name = "syslet-rw", |
| 287 | .version = FIO_IOOPS_VERSION, |
| 288 | .init = fio_syslet_init, |
| 289 | .queue = fio_syslet_queue, |
| 290 | .getevents = fio_syslet_getevents, |
| 291 | .event = fio_syslet_event, |
| 292 | .cleanup = fio_syslet_cleanup, |
| 293 | .open_file = generic_open_file, |
| 294 | .close_file = generic_close_file, |
| 295 | .get_file_size = generic_get_file_size, |
| 296 | }; |
| 297 | |
| 298 | #else /* FIO_HAVE_SYSLET */ |
| 299 | |
| 300 | /* |
| 301 | * When we have a proper configure system in place, we simply wont build |
| 302 | * and install this io engine. For now install a crippled version that |
| 303 | * just complains and fails to load. |
| 304 | */ |
| 305 | static int fio_syslet_init(struct thread_data fio_unused *td) |
| 306 | { |
| 307 | log_err("fio: syslet not available\n"); |
| 308 | return 1; |
| 309 | } |
| 310 | |
| 311 | static struct ioengine_ops ioengine = { |
| 312 | .name = "syslet-rw", |
| 313 | .version = FIO_IOOPS_VERSION, |
| 314 | .init = fio_syslet_init, |
| 315 | }; |
| 316 | |
| 317 | #endif /* FIO_HAVE_SYSLET */ |
| 318 | |
| 319 | static void fio_init fio_syslet_register(void) |
| 320 | { |
| 321 | register_ioengine(&ioengine); |
| 322 | } |
| 323 | |
| 324 | static void fio_exit fio_syslet_unregister(void) |
| 325 | { |
| 326 | unregister_ioengine(&ioengine); |
| 327 | } |