t/aio-ring.c

   1 /*
   2  * gcc -D_GNU_SOURCE -Wall -O2 -o aio-ring aio-ring.c  -lpthread -laio
   3  */
   4 #include <stdio.h>
   5 #include <errno.h>
   6 #include <assert.h>
   7 #include <stdlib.h>
   8 #include <stddef.h>
   9 #include <signal.h>
  10 #include <inttypes.h>
  11
  12 #include <sys/types.h>
  13 #include <sys/stat.h>
  14 #include <sys/ioctl.h>
  15 #include <sys/syscall.h>
  16 #include <sys/resource.h>
  17 #include <sys/mman.h>
  18 #include <linux/fs.h>
  19 #include <fcntl.h>
  20 #include <unistd.h>
  21 #include <libaio.h>
  22 #include <string.h>
  23 #include <pthread.h>
  24 #include <sched.h>
  25
  26 #include "../arch/arch.h"
  27
  28 #define IOCTX_FLAG_SCQRING      (1 << 0)        /* Use SQ/CQ rings */
  29 #define IOCTX_FLAG_IOPOLL       (1 << 1)
  30 #define IOCTX_FLAG_FIXEDBUFS    (1 << 2)
  31 #define IOCTX_FLAG_SQTHREAD     (1 << 3)        /* Use SQ thread */
  32 #define IOCTX_FLAG_SQWQ         (1 << 4)        /* Use SQ wq */
  33 #define IOCTX_FLAG_SQPOLL       (1 << 5)
  34
  35 #define IOEV_RES2_CACHEHIT      (1 << 0)
  36
  37 #define barrier()       __asm__ __volatile__("": : :"memory")
  38
  39 #define min(a, b)               ((a < b) ? (a) : (b))
  40
  41 typedef uint64_t u64;
  42 typedef uint32_t u32;
  43 typedef uint16_t u16;
  44
  45 #define IORING_OFF_SQ_RING      0ULL
  46 #define IORING_OFF_CQ_RING      0x8000000ULL
  47 #define IORING_OFF_IOCB         0x10000000ULL
  48
  49 struct aio_uring_offsets {
  50         u32 head;
  51         u32 tail;
  52         u32 ring_mask;
  53         u32 ring_entries;
  54         u32 flags;
  55         u32 elems;
  56 };
  57
  58 struct aio_uring_params {
  59         u32 sq_entries;
  60         u32 cq_entries;
  61         u32 flags;
  62         u16 sq_thread_cpu;
  63         u16 resv[9];
  64         struct aio_uring_offsets sq_off;
  65         struct aio_uring_offsets cq_off;
  66 };
  67
  68 struct aio_sq_ring {
  69         u32 *head;
  70         u32 *tail;
  71         u32 *ring_mask;
  72         u32 *ring_entries;
  73         u32 *array;
  74 };
  75
  76 struct aio_cq_ring {
  77         u32 *head;
  78         u32 *tail;
  79         u32 *ring_mask;
  80         u32 *ring_entries;
  81         struct io_event *events;
  82 };
  83
  84 #define IORING_ENTER_GETEVENTS  (1 << 0)
  85
  86 #define DEPTH                   32
  87
  88 #define BATCH_SUBMIT            8
  89 #define BATCH_COMPLETE          8
  90
  91 #define BS                      4096
  92
  93 static unsigned sq_ring_mask, cq_ring_mask;
  94
  95 struct submitter {
  96         pthread_t thread;
  97         unsigned long max_blocks;
  98         int fd;
  99         struct drand48_data rand;
 100         struct aio_sq_ring sq_ring;
 101         struct iocb *iocbs;
 102         struct iovec iovecs[DEPTH];
 103         struct aio_cq_ring cq_ring;
 104         int inflight;
 105         unsigned long reaps;
 106         unsigned long done;
 107         unsigned long calls;
 108         unsigned long cachehit, cachemiss;
 109         volatile int finish;
 110         char filename[128];
 111 };
 112
 113 static struct submitter submitters[1];
 114 static volatile int finish;
 115
 116 static int polled = 0;          /* use IO polling */
 117 static int fixedbufs = 0;       /* use fixed user buffers */
 118 static int buffered = 1;        /* use buffered IO, not O_DIRECT */
 119 static int sq_thread = 0;       /* use kernel submission thread */
 120 static int sq_thread_cpu = 0;   /* pin above thread to this CPU */
 121
 122 static int io_uring_setup(unsigned entries, struct iovec *iovecs,
 123                           struct aio_uring_params *p)
 124 {
 125         return syscall(__NR_sys_io_uring_setup, entries, iovecs, p);
 126 }
 127
 128 static int io_uring_enter(struct submitter *s, unsigned int to_submit,
 129                           unsigned int min_complete, unsigned int flags)
 130 {
 131         return syscall(__NR_sys_io_uring_enter, s->fd, to_submit, min_complete,
 132                         flags);
 133 }
 134
 135 static int gettid(void)
 136 {
 137         return syscall(__NR_gettid);
 138 }
 139
 140 static void init_io(struct submitter *s, int fd, unsigned index)
 141 {
 142         struct iocb *iocb = &s->iocbs[index];
 143         unsigned long offset;
 144         long r;
 145
 146         lrand48_r(&s->rand, &r);
 147         offset = (r % (s->max_blocks - 1)) * BS;
 148
 149         iocb->aio_fildes = fd;
 150         iocb->aio_lio_opcode = IO_CMD_PREAD;
 151         iocb->u.c.buf = s->iovecs[index].iov_base;
 152         iocb->u.c.nbytes = BS;
 153         iocb->u.c.offset = offset;
 154 }
 155
 156 static int prep_more_ios(struct submitter *s, int fd, int max_ios)
 157 {
 158         struct aio_sq_ring *ring = &s->sq_ring;
 159         u32 index, tail, next_tail, prepped = 0;
 160
 161         next_tail = tail = *ring->tail;
 162         do {
 163                 next_tail++;
 164                 barrier();
 165                 if (next_tail == *ring->head)
 166                         break;
 167
 168                 index = tail & sq_ring_mask;
 169                 init_io(s, fd, index);
 170                 ring->array[index] = index;
 171                 prepped++;
 172                 tail = next_tail;
 173         } while (prepped < max_ios);
 174
 175         if (*ring->tail != tail) {
 176                 /* order tail store with writes to iocbs above */
 177                 barrier();
 178                 *ring->tail = tail;
 179                 barrier();
 180         }
 181         return prepped;
 182 }
 183
 184 static int get_file_size(int fd, unsigned long *blocks)
 185 {
 186         struct stat st;
 187
 188         if (fstat(fd, &st) < 0)
 189                 return -1;
 190         if (S_ISBLK(st.st_mode)) {
 191                 unsigned long long bytes;
 192
 193                 if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
 194                         return -1;
 195
 196                 *blocks = bytes / BS;
 197                 return 0;
 198         } else if (S_ISREG(st.st_mode)) {
 199                 *blocks = st.st_size / BS;
 200                 return 0;
 201         }
 202
 203         return -1;
 204 }
 205
 206 static int reap_events(struct submitter *s)
 207 {
 208         struct aio_cq_ring *ring = &s->cq_ring;
 209         struct io_event *ev;
 210         u32 head, reaped = 0;
 211
 212         head = *ring->head;
 213         do {
 214                 barrier();
 215                 if (head == *ring->tail)
 216                         break;
 217                 ev = &ring->events[head & cq_ring_mask];
 218                 if (ev->res != BS) {
 219                         struct iocb *iocb = ev->obj;
 220
 221                         printf("io: unexpected ret=%ld\n", ev->res);
 222                         printf("offset=%lu, size=%lu\n", (unsigned long) iocb->u.c.offset, (unsigned long) iocb->u.c.nbytes);
 223                         return -1;
 224                 }
 225                 if (ev->res2 & IOEV_RES2_CACHEHIT)
 226                         s->cachehit++;
 227                 else
 228                         s->cachemiss++;
 229                 reaped++;
 230                 head++;
 231         } while (1);
 232
 233         s->inflight -= reaped;
 234         *ring->head = head;
 235         barrier();
 236         return reaped;
 237 }
 238
 239 static void *submitter_fn(void *data)
 240 {
 241         struct submitter *s = data;
 242         int fd, ret, prepped, flags;
 243
 244         printf("submitter=%d\n", gettid());
 245
 246         flags = O_RDONLY;
 247         if (!buffered)
 248                 flags |= O_DIRECT;
 249         fd = open(s->filename, flags);
 250         if (fd < 0) {
 251                 perror("open");
 252                 goto done;
 253         }
 254
 255         if (get_file_size(fd, &s->max_blocks)) {
 256                 printf("failed getting size of device/file\n");
 257                 goto err;
 258         }
 259         if (!s->max_blocks) {
 260                 printf("Zero file/device size?\n");
 261                 goto err;
 262         }
 263
 264         s->max_blocks--;
 265
 266         srand48_r(pthread_self(), &s->rand);
 267
 268         prepped = 0;
 269         do {
 270                 int to_wait, to_submit, this_reap;
 271
 272                 if (!prepped && s->inflight < DEPTH)
 273                         prepped = prep_more_ios(s, fd, min(DEPTH - s->inflight, BATCH_SUBMIT));
 274                 s->inflight += prepped;
 275 submit_more:
 276                 to_submit = prepped;
 277 submit:
 278                 if (s->inflight + BATCH_SUBMIT < DEPTH)
 279                         to_wait = 0;
 280                 else
 281                         to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
 282
 283                 ret = io_uring_enter(s, to_submit, to_wait, IORING_ENTER_GETEVENTS);
 284                 s->calls++;
 285
 286                 this_reap = reap_events(s);
 287                 if (this_reap == -1)
 288                         break;
 289                 s->reaps += this_reap;
 290
 291                 if (ret >= 0) {
 292                         if (!ret) {
 293                                 to_submit = 0;
 294                                 if (s->inflight)
 295                                         goto submit;
 296                                 continue;
 297                         } else if (ret < to_submit) {
 298                                 int diff = to_submit - ret;
 299
 300                                 s->done += ret;
 301                                 prepped -= diff;
 302                                 goto submit_more;
 303                         }
 304                         s->done += ret;
 305                         prepped = 0;
 306                         continue;
 307                 } else if (ret < 0) {
 308                         if ((ret == -1 && errno == EAGAIN) || ret == -EAGAIN) {
 309                                 if (s->finish)
 310                                         break;
 311                                 if (this_reap)
 312                                         goto submit;
 313                                 to_submit = 0;
 314                                 goto submit;
 315                         }
 316                         if (ret == -1)
 317                                 printf("io_submit: %s\n", strerror(errno));
 318                         else
 319                                 printf("io_submit: %s\n", strerror(-ret));
 320                         break;
 321                 }
 322         } while (!s->finish);
 323 err:
 324         close(fd);
 325 done:
 326         finish = 1;
 327         return NULL;
 328 }
 329
 330 static void sig_int(int sig)
 331 {
 332         printf("Exiting on signal %d\n", sig);
 333         submitters[0].finish = 1;
 334         finish = 1;
 335 }
 336
 337 static void arm_sig_int(void)
 338 {
 339         struct sigaction act;
 340
 341         memset(&act, 0, sizeof(act));
 342         act.sa_handler = sig_int;
 343         act.sa_flags = SA_RESTART;
 344         sigaction(SIGINT, &act, NULL);
 345 }
 346
 347 static int setup_ring(struct submitter *s)
 348 {
 349         struct aio_sq_ring *sring = &s->sq_ring;
 350         struct aio_cq_ring *cring = &s->cq_ring;
 351         struct aio_uring_params p;
 352         void *ptr;
 353         int fd;
 354
 355         memset(&p, 0, sizeof(p));
 356
 357         p.flags = IOCTX_FLAG_SCQRING;
 358         if (polled)
 359                 p.flags |= IOCTX_FLAG_IOPOLL;
 360         if (fixedbufs)
 361                 p.flags |= IOCTX_FLAG_FIXEDBUFS;
 362         if (buffered)
 363                 p.flags |= IOCTX_FLAG_SQWQ;
 364         else if (sq_thread) {
 365                 p.flags |= IOCTX_FLAG_SQTHREAD;
 366                 p.sq_thread_cpu = sq_thread_cpu;
 367         }
 368
 369         if (fixedbufs)
 370                 fd = io_uring_setup(DEPTH, s->iovecs, &p);
 371         else
 372                 fd = io_uring_setup(DEPTH, NULL, &p);
 373         if (fd < 0) {
 374                 perror("io_uring_setup");
 375                 return 1;
 376         }
 377
 378         s->fd = fd;
 379
 380         ptr = mmap(0, p.sq_off.elems + p.sq_entries * sizeof(u32),
 381                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
 382                         fd, IORING_OFF_SQ_RING);
 383         printf("sq_ring ptr = 0x%p\n", ptr);
 384         sring->head = ptr + p.sq_off.head;
 385         sring->tail = ptr + p.sq_off.tail;
 386         sring->ring_mask = ptr + p.sq_off.ring_mask;
 387         sring->ring_entries = ptr + p.sq_off.ring_entries;
 388         sring->array = ptr + p.sq_off.elems;
 389         sq_ring_mask = *sring->ring_mask;
 390
 391         s->iocbs = mmap(0, p.sq_entries * sizeof(struct iocb), PROT_READ | PROT_WRITE,
 392                         MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_IOCB);
 393         printf("iocbs ptr   = 0x%p\n", s->iocbs);
 394
 395         ptr = mmap(0, p.cq_off.elems + p.cq_entries * sizeof(struct io_event),
 396                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
 397                         fd, IORING_OFF_CQ_RING);
 398         printf("cq_ring ptr = 0x%p\n", ptr);
 399         cring->head = ptr + p.cq_off.head;
 400         cring->tail = ptr + p.cq_off.tail;
 401         cring->ring_mask = ptr + p.cq_off.ring_mask;
 402         cring->ring_entries = ptr + p.cq_off.ring_entries;
 403         cring->events = ptr + p.cq_off.elems;
 404         cq_ring_mask = *cring->ring_mask;
 405         return 0;
 406 }
 407
 408 int main(int argc, char *argv[])
 409 {
 410         struct submitter *s = &submitters[0];
 411         unsigned long done, calls, reap, cache_hit, cache_miss;
 412         int err, i;
 413         struct rlimit rlim;
 414         void *ret;
 415
 416         if (argc < 2) {
 417                 printf("%s: filename\n", argv[0]);
 418                 return 1;
 419         }
 420
 421         rlim.rlim_cur = RLIM_INFINITY;
 422         rlim.rlim_max = RLIM_INFINITY;
 423         if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
 424                 perror("setrlimit");
 425                 return 1;
 426         }
 427
 428         arm_sig_int();
 429
 430         for (i = 0; i < DEPTH; i++) {
 431                 void *buf;
 432
 433                 if (posix_memalign(&buf, BS, BS)) {
 434                         printf("failed alloc\n");
 435                         return 1;
 436                 }
 437                 s->iovecs[i].iov_base = buf;
 438                 s->iovecs[i].iov_len = BS;
 439         }
 440
 441         err = setup_ring(s);
 442         if (err) {
 443                 printf("ring setup failed: %s, %d\n", strerror(errno), err);
 444                 return 1;
 445         }
 446         printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
 447         printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
 448         strcpy(s->filename, argv[1]);
 449
 450         pthread_create(&s->thread, NULL, submitter_fn, s);
 451
 452         cache_hit = cache_miss = reap = calls = done = 0;
 453         do {
 454                 unsigned long this_done = 0;
 455                 unsigned long this_reap = 0;
 456                 unsigned long this_call = 0;
 457                 unsigned long this_cache_hit = 0;
 458                 unsigned long this_cache_miss = 0;
 459                 unsigned long rpc = 0, ipc = 0;
 460                 double hit = 0.0;
 461
 462                 sleep(1);
 463                 this_done += s->done;
 464                 this_call += s->calls;
 465                 this_reap += s->reaps;
 466                 this_cache_hit += s->cachehit;
 467                 this_cache_miss += s->cachemiss;
 468                 if (this_cache_hit && this_cache_miss) {
 469                         unsigned long hits, total;
 470
 471                         hits = this_cache_hit - cache_hit;
 472                         total = hits + this_cache_miss - cache_miss;
 473                         hit = (double) hits / (double) total;
 474                         hit *= 100.0;
 475                 }
 476                 if (this_call - calls) {
 477                         rpc = (this_done - done) / (this_call - calls);
 478                         ipc = (this_reap - reap) / (this_call - calls);
 479                 }
 480                 printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%u tail=%u), Cachehit=%0.2f%%\n",
 481                                 this_done - done, rpc, ipc, s->inflight,
 482                                 *s->cq_ring.head, *s->cq_ring.tail, hit);
 483                 done = this_done;
 484                 calls = this_call;
 485                 reap = this_reap;
 486                 cache_hit = s->cachehit;
 487                 cache_miss = s->cachemiss;
 488         } while (!finish);
 489
 490         pthread_join(s->thread, &ret);
 491         return 0;
 492 }