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_sqring_offsets {
  50         u32 head;
  51         u32 tail;
  52         u32 ring_mask;
  53         u32 ring_entries;
  54         u32 flags;
  55         u32 dropped;
  56         u32 array;
  57         u32 resv[3];
  58 };
  59
  60 struct aio_cqring_offsets {
  61         u32 head;
  62         u32 tail;
  63         u32 ring_mask;
  64         u32 ring_entries;
  65         u32 overflow;
  66         u32 events;
  67         u32 resv[4];
  68 };
  69
  70 struct aio_uring_params {
  71         u32 sq_entries;
  72         u32 cq_entries;
  73         u32 flags;
  74         u16 sq_thread_cpu;
  75         u16 resv[9];
  76         struct aio_sqring_offsets sq_off;
  77         struct aio_cqring_offsets cq_off;
  78 };
  79
  80 struct aio_sq_ring {
  81         u32 *head;
  82         u32 *tail;
  83         u32 *ring_mask;
  84         u32 *ring_entries;
  85         u32 *array;
  86 };
  87
  88 struct aio_cq_ring {
  89         u32 *head;
  90         u32 *tail;
  91         u32 *ring_mask;
  92         u32 *ring_entries;
  93         struct io_event *events;
  94 };
  95
  96 #define IORING_ENTER_GETEVENTS  (1 << 0)
  97
  98 #define DEPTH                   32
  99
 100 #define BATCH_SUBMIT            8
 101 #define BATCH_COMPLETE          8
 102
 103 #define BS                      4096
 104
 105 static unsigned sq_ring_mask, cq_ring_mask;
 106
 107 struct submitter {
 108         pthread_t thread;
 109         unsigned long max_blocks;
 110         int fd;
 111         struct drand48_data rand;
 112         struct aio_sq_ring sq_ring;
 113         struct iocb *iocbs;
 114         struct iovec iovecs[DEPTH];
 115         struct aio_cq_ring cq_ring;
 116         int inflight;
 117         unsigned long reaps;
 118         unsigned long done;
 119         unsigned long calls;
 120         unsigned long cachehit, cachemiss;
 121         volatile int finish;
 122         char filename[128];
 123 };
 124
 125 static struct submitter submitters[1];
 126 static volatile int finish;
 127
 128 static int polled = 0;          /* use IO polling */
 129 static int fixedbufs = 0;       /* use fixed user buffers */
 130 static int buffered = 1;        /* use buffered IO, not O_DIRECT */
 131 static int sq_thread = 0;       /* use kernel submission thread */
 132 static int sq_thread_cpu = 0;   /* pin above thread to this CPU */
 133
 134 static int io_uring_setup(unsigned entries, struct iovec *iovecs,
 135                           struct aio_uring_params *p)
 136 {
 137         return syscall(__NR_sys_io_uring_setup, entries, iovecs, p);
 138 }
 139
 140 static int io_uring_enter(struct submitter *s, unsigned int to_submit,
 141                           unsigned int min_complete, unsigned int flags)
 142 {
 143         return syscall(__NR_sys_io_uring_enter, s->fd, to_submit, min_complete,
 144                         flags);
 145 }
 146
 147 static int gettid(void)
 148 {
 149         return syscall(__NR_gettid);
 150 }
 151
 152 static void init_io(struct submitter *s, int fd, unsigned index)
 153 {
 154         struct iocb *iocb = &s->iocbs[index];
 155         unsigned long offset;
 156         long r;
 157
 158         lrand48_r(&s->rand, &r);
 159         offset = (r % (s->max_blocks - 1)) * BS;
 160
 161         iocb->aio_fildes = fd;
 162         iocb->aio_lio_opcode = IO_CMD_PREAD;
 163         iocb->u.c.buf = s->iovecs[index].iov_base;
 164         iocb->u.c.nbytes = BS;
 165         iocb->u.c.offset = offset;
 166 }
 167
 168 static int prep_more_ios(struct submitter *s, int fd, int max_ios)
 169 {
 170         struct aio_sq_ring *ring = &s->sq_ring;
 171         u32 index, tail, next_tail, prepped = 0;
 172
 173         next_tail = tail = *ring->tail;
 174         do {
 175                 next_tail++;
 176                 barrier();
 177                 if (next_tail == *ring->head)
 178                         break;
 179
 180                 index = tail & sq_ring_mask;
 181                 init_io(s, fd, index);
 182                 ring->array[index] = index;
 183                 prepped++;
 184                 tail = next_tail;
 185         } while (prepped < max_ios);
 186
 187         if (*ring->tail != tail) {
 188                 /* order tail store with writes to iocbs above */
 189                 barrier();
 190                 *ring->tail = tail;
 191                 barrier();
 192         }
 193         return prepped;
 194 }
 195
 196 static int get_file_size(int fd, unsigned long *blocks)
 197 {
 198         struct stat st;
 199
 200         if (fstat(fd, &st) < 0)
 201                 return -1;
 202         if (S_ISBLK(st.st_mode)) {
 203                 unsigned long long bytes;
 204
 205                 if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
 206                         return -1;
 207
 208                 *blocks = bytes / BS;
 209                 return 0;
 210         } else if (S_ISREG(st.st_mode)) {
 211                 *blocks = st.st_size / BS;
 212                 return 0;
 213         }
 214
 215         return -1;
 216 }
 217
 218 static int reap_events(struct submitter *s)
 219 {
 220         struct aio_cq_ring *ring = &s->cq_ring;
 221         struct io_event *ev;
 222         u32 head, reaped = 0;
 223
 224         head = *ring->head;
 225         do {
 226                 barrier();
 227                 if (head == *ring->tail)
 228                         break;
 229                 ev = &ring->events[head & cq_ring_mask];
 230                 if (ev->res != BS) {
 231                         struct iocb *iocb = ev->obj;
 232
 233                         printf("io: unexpected ret=%ld\n", ev->res);
 234                         printf("offset=%lu, size=%lu\n", (unsigned long) iocb->u.c.offset, (unsigned long) iocb->u.c.nbytes);
 235                         return -1;
 236                 }
 237                 if (ev->res2 & IOEV_RES2_CACHEHIT)
 238                         s->cachehit++;
 239                 else
 240                         s->cachemiss++;
 241                 reaped++;
 242                 head++;
 243         } while (1);
 244
 245         s->inflight -= reaped;
 246         *ring->head = head;
 247         barrier();
 248         return reaped;
 249 }
 250
 251 static void *submitter_fn(void *data)
 252 {
 253         struct submitter *s = data;
 254         int fd, ret, prepped, flags;
 255
 256         printf("submitter=%d\n", gettid());
 257
 258         flags = O_RDONLY;
 259         if (!buffered)
 260                 flags |= O_DIRECT;
 261         fd = open(s->filename, flags);
 262         if (fd < 0) {
 263                 perror("open");
 264                 goto done;
 265         }
 266
 267         if (get_file_size(fd, &s->max_blocks)) {
 268                 printf("failed getting size of device/file\n");
 269                 goto err;
 270         }
 271         if (!s->max_blocks) {
 272                 printf("Zero file/device size?\n");
 273                 goto err;
 274         }
 275
 276         s->max_blocks--;
 277
 278         srand48_r(pthread_self(), &s->rand);
 279
 280         prepped = 0;
 281         do {
 282                 int to_wait, to_submit, this_reap;
 283
 284                 if (!prepped && s->inflight < DEPTH)
 285                         prepped = prep_more_ios(s, fd, min(DEPTH - s->inflight, BATCH_SUBMIT));
 286                 s->inflight += prepped;
 287 submit_more:
 288                 to_submit = prepped;
 289 submit:
 290                 if (s->inflight + BATCH_SUBMIT < DEPTH)
 291                         to_wait = 0;
 292                 else
 293                         to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
 294
 295                 ret = io_uring_enter(s, to_submit, to_wait, IORING_ENTER_GETEVENTS);
 296                 s->calls++;
 297
 298                 this_reap = reap_events(s);
 299                 if (this_reap == -1)
 300                         break;
 301                 s->reaps += this_reap;
 302
 303                 if (ret >= 0) {
 304                         if (!ret) {
 305                                 to_submit = 0;
 306                                 if (s->inflight)
 307                                         goto submit;
 308                                 continue;
 309                         } else if (ret < to_submit) {
 310                                 int diff = to_submit - ret;
 311
 312                                 s->done += ret;
 313                                 prepped -= diff;
 314                                 goto submit_more;
 315                         }
 316                         s->done += ret;
 317                         prepped = 0;
 318                         continue;
 319                 } else if (ret < 0) {
 320                         if (errno == EAGAIN) {
 321                                 if (s->finish)
 322                                         break;
 323                                 if (this_reap)
 324                                         goto submit;
 325                                 to_submit = 0;
 326                                 goto submit;
 327                         }
 328                         printf("io_submit: %s\n", strerror(errno));
 329                         break;
 330                 }
 331         } while (!s->finish);
 332 err:
 333         close(fd);
 334 done:
 335         finish = 1;
 336         return NULL;
 337 }
 338
 339 static void sig_int(int sig)
 340 {
 341         printf("Exiting on signal %d\n", sig);
 342         submitters[0].finish = 1;
 343         finish = 1;
 344 }
 345
 346 static void arm_sig_int(void)
 347 {
 348         struct sigaction act;
 349
 350         memset(&act, 0, sizeof(act));
 351         act.sa_handler = sig_int;
 352         act.sa_flags = SA_RESTART;
 353         sigaction(SIGINT, &act, NULL);
 354 }
 355
 356 static int setup_ring(struct submitter *s)
 357 {
 358         struct aio_sq_ring *sring = &s->sq_ring;
 359         struct aio_cq_ring *cring = &s->cq_ring;
 360         struct aio_uring_params p;
 361         void *ptr;
 362         int fd;
 363
 364         memset(&p, 0, sizeof(p));
 365
 366         p.flags = IOCTX_FLAG_SCQRING;
 367         if (polled)
 368                 p.flags |= IOCTX_FLAG_IOPOLL;
 369         if (fixedbufs)
 370                 p.flags |= IOCTX_FLAG_FIXEDBUFS;
 371         if (buffered)
 372                 p.flags |= IOCTX_FLAG_SQWQ;
 373         else if (sq_thread) {
 374                 p.flags |= IOCTX_FLAG_SQTHREAD;
 375                 p.sq_thread_cpu = sq_thread_cpu;
 376         }
 377
 378         if (fixedbufs)
 379                 fd = io_uring_setup(DEPTH, s->iovecs, &p);
 380         else
 381                 fd = io_uring_setup(DEPTH, NULL, &p);
 382         if (fd < 0) {
 383                 perror("io_uring_setup");
 384                 return 1;
 385         }
 386
 387         s->fd = fd;
 388
 389         ptr = mmap(0, p.sq_off.array + p.sq_entries * sizeof(u32),
 390                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
 391                         fd, IORING_OFF_SQ_RING);
 392         printf("sq_ring ptr = 0x%p\n", ptr);
 393         sring->head = ptr + p.sq_off.head;
 394         sring->tail = ptr + p.sq_off.tail;
 395         sring->ring_mask = ptr + p.sq_off.ring_mask;
 396         sring->ring_entries = ptr + p.sq_off.ring_entries;
 397         sring->array = ptr + p.sq_off.array;
 398         sq_ring_mask = *sring->ring_mask;
 399
 400         s->iocbs = mmap(0, p.sq_entries * sizeof(struct iocb), PROT_READ | PROT_WRITE,
 401                         MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_IOCB);
 402         printf("iocbs ptr   = 0x%p\n", s->iocbs);
 403
 404         ptr = mmap(0, p.cq_off.events + p.cq_entries * sizeof(struct io_event),
 405                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
 406                         fd, IORING_OFF_CQ_RING);
 407         printf("cq_ring ptr = 0x%p\n", ptr);
 408         cring->head = ptr + p.cq_off.head;
 409         cring->tail = ptr + p.cq_off.tail;
 410         cring->ring_mask = ptr + p.cq_off.ring_mask;
 411         cring->ring_entries = ptr + p.cq_off.ring_entries;
 412         cring->events = ptr + p.cq_off.events;
 413         cq_ring_mask = *cring->ring_mask;
 414         return 0;
 415 }
 416
 417 int main(int argc, char *argv[])
 418 {
 419         struct submitter *s = &submitters[0];
 420         unsigned long done, calls, reap, cache_hit, cache_miss;
 421         int err, i;
 422         struct rlimit rlim;
 423         void *ret;
 424
 425         if (argc < 2) {
 426                 printf("%s: filename\n", argv[0]);
 427                 return 1;
 428         }
 429
 430         rlim.rlim_cur = RLIM_INFINITY;
 431         rlim.rlim_max = RLIM_INFINITY;
 432         if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
 433                 perror("setrlimit");
 434                 return 1;
 435         }
 436
 437         arm_sig_int();
 438
 439         for (i = 0; i < DEPTH; i++) {
 440                 void *buf;
 441
 442                 if (posix_memalign(&buf, BS, BS)) {
 443                         printf("failed alloc\n");
 444                         return 1;
 445                 }
 446                 s->iovecs[i].iov_base = buf;
 447                 s->iovecs[i].iov_len = BS;
 448         }
 449
 450         err = setup_ring(s);
 451         if (err) {
 452                 printf("ring setup failed: %s, %d\n", strerror(errno), err);
 453                 return 1;
 454         }
 455         printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
 456         printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
 457         strcpy(s->filename, argv[1]);
 458
 459         pthread_create(&s->thread, NULL, submitter_fn, s);
 460
 461         cache_hit = cache_miss = reap = calls = done = 0;
 462         do {
 463                 unsigned long this_done = 0;
 464                 unsigned long this_reap = 0;
 465                 unsigned long this_call = 0;
 466                 unsigned long this_cache_hit = 0;
 467                 unsigned long this_cache_miss = 0;
 468                 unsigned long rpc = 0, ipc = 0;
 469                 double hit = 0.0;
 470
 471                 sleep(1);
 472                 this_done += s->done;
 473                 this_call += s->calls;
 474                 this_reap += s->reaps;
 475                 this_cache_hit += s->cachehit;
 476                 this_cache_miss += s->cachemiss;
 477                 if (this_cache_hit && this_cache_miss) {
 478                         unsigned long hits, total;
 479
 480                         hits = this_cache_hit - cache_hit;
 481                         total = hits + this_cache_miss - cache_miss;
 482                         hit = (double) hits / (double) total;
 483                         hit *= 100.0;
 484                 }
 485                 if (this_call - calls) {
 486                         rpc = (this_done - done) / (this_call - calls);
 487                         ipc = (this_reap - reap) / (this_call - calls);
 488                 }
 489                 printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%u tail=%u), Cachehit=%0.2f%%\n",
 490                                 this_done - done, rpc, ipc, s->inflight,
 491                                 *s->cq_ring.head, *s->cq_ring.tail, hit);
 492                 done = this_done;
 493                 calls = this_call;
 494                 reap = this_reap;
 495                 cache_hit = s->cachehit;
 496                 cache_miss = s->cachemiss;
 497         } while (!finish);
 498
 499         pthread_join(s->thread, &ret);
 500         return 0;
 501 }