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