t/io_uring.c

   1 #include <stdio.h>
   2 #include <errno.h>
   3 #include <assert.h>
   4 #include <stdlib.h>
   5 #include <stddef.h>
   6 #include <signal.h>
   7 #include <inttypes.h>
   8
   9 #include <sys/types.h>
  10 #include <sys/stat.h>
  11 #include <sys/ioctl.h>
  12 #include <sys/syscall.h>
  13 #include <sys/resource.h>
  14 #include <sys/mman.h>
  15 #include <sys/uio.h>
  16 #include <linux/fs.h>
  17 #include <fcntl.h>
  18 #include <unistd.h>
  19 #include <string.h>
  20 #include <pthread.h>
  21 #include <sched.h>
  22
  23 #include "../arch/arch.h"
  24 #include "../os/io_uring.h"
  25
  26 #define barrier()       __asm__ __volatile__("": : :"memory")
  27
  28 #define min(a, b)               ((a < b) ? (a) : (b))
  29
  30 struct io_sq_ring {
  31         unsigned *head;
  32         unsigned *tail;
  33         unsigned *ring_mask;
  34         unsigned *ring_entries;
  35         unsigned *array;
  36 };
  37
  38 struct io_cq_ring {
  39         unsigned *head;
  40         unsigned *tail;
  41         unsigned *ring_mask;
  42         unsigned *ring_entries;
  43         struct io_uring_event *events;
  44 };
  45
  46 #define DEPTH                   32
  47
  48 #define BATCH_SUBMIT            8
  49 #define BATCH_COMPLETE          8
  50
  51 #define BS                      4096
  52
  53 static unsigned sq_ring_mask, cq_ring_mask;
  54
  55 struct submitter {
  56         pthread_t thread;
  57         unsigned long max_blocks;
  58         int ring_fd;
  59         struct drand48_data rand;
  60         struct io_sq_ring sq_ring;
  61         struct io_uring_iocb *iocbs;
  62         struct iovec iovecs[DEPTH];
  63         struct io_cq_ring cq_ring;
  64         int inflight;
  65         unsigned long reaps;
  66         unsigned long done;
  67         unsigned long calls;
  68         unsigned long cachehit, cachemiss;
  69         volatile int finish;
  70         char filename[128];
  71 };
  72
  73 static struct submitter submitters[1];
  74 static volatile int finish;
  75
  76 static int polled = 0;          /* use IO polling */
  77 static int fixedbufs = 0;       /* use fixed user buffers */
  78 static int buffered = 1;        /* use buffered IO, not O_DIRECT */
  79 static int sq_thread = 0;       /* use kernel submission thread */
  80 static int sq_thread_cpu = 0;   /* pin above thread to this CPU */
  81
  82 static int io_uring_setup(unsigned entries, struct iovec *iovecs,
  83                           struct io_uring_params *p)
  84 {
  85         return syscall(__NR_sys_io_uring_setup, entries, iovecs, p);
  86 }
  87
  88 static int io_uring_enter(struct submitter *s, unsigned int to_submit,
  89                           unsigned int min_complete, unsigned int flags)
  90 {
  91         return syscall(__NR_sys_io_uring_enter, s->ring_fd, to_submit,
  92                         min_complete, flags);
  93 }
  94
  95 static int gettid(void)
  96 {
  97         return syscall(__NR_gettid);
  98 }
  99
 100 static void init_io(struct submitter *s, int fd, unsigned index)
 101 {
 102         struct io_uring_iocb *iocb = &s->iocbs[index];
 103         unsigned long offset;
 104         long r;
 105
 106         lrand48_r(&s->rand, &r);
 107         offset = (r % (s->max_blocks - 1)) * BS;
 108
 109         iocb->opcode = IORING_OP_READ;
 110         iocb->flags = 0;
 111         iocb->ioprio = 0;
 112         iocb->fd = fd;
 113         iocb->off = offset;
 114         iocb->addr = s->iovecs[index].iov_base;
 115         iocb->len = BS;
 116 }
 117
 118 static int prep_more_ios(struct submitter *s, int fd, int max_ios)
 119 {
 120         struct io_sq_ring *ring = &s->sq_ring;
 121         unsigned index, tail, next_tail, prepped = 0;
 122
 123         next_tail = tail = *ring->tail;
 124         do {
 125                 next_tail++;
 126                 barrier();
 127                 if (next_tail == *ring->head)
 128                         break;
 129
 130                 index = tail & sq_ring_mask;
 131                 init_io(s, fd, index);
 132                 ring->array[index] = index;
 133                 prepped++;
 134                 tail = next_tail;
 135         } while (prepped < max_ios);
 136
 137         if (*ring->tail != tail) {
 138                 /* order tail store with writes to iocbs above */
 139                 barrier();
 140                 *ring->tail = tail;
 141                 barrier();
 142         }
 143         return prepped;
 144 }
 145
 146 static int get_file_size(int fd, unsigned long *blocks)
 147 {
 148         struct stat st;
 149
 150         if (fstat(fd, &st) < 0)
 151                 return -1;
 152         if (S_ISBLK(st.st_mode)) {
 153                 unsigned long long bytes;
 154
 155                 if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
 156                         return -1;
 157
 158                 *blocks = bytes / BS;
 159                 return 0;
 160         } else if (S_ISREG(st.st_mode)) {
 161                 *blocks = st.st_size / BS;
 162                 return 0;
 163         }
 164
 165         return -1;
 166 }
 167
 168 static int reap_events(struct submitter *s)
 169 {
 170         struct io_cq_ring *ring = &s->cq_ring;
 171         struct io_uring_event *ev;
 172         unsigned head, reaped = 0;
 173
 174         head = *ring->head;
 175         do {
 176                 barrier();
 177                 if (head == *ring->tail)
 178                         break;
 179                 ev = &ring->events[head & cq_ring_mask];
 180                 if (ev->res != BS) {
 181                         struct io_uring_iocb *iocb = &s->iocbs[ev->index];
 182
 183                         printf("io: unexpected ret=%d\n", ev->res);
 184                         printf("offset=%lu, size=%lu\n",
 185                                         (unsigned long) iocb->off,
 186                                         (unsigned long) iocb->len);
 187                         return -1;
 188                 }
 189                 if (ev->flags & IOEV_FLAG_CACHEHIT)
 190                         s->cachehit++;
 191                 else
 192                         s->cachemiss++;
 193                 reaped++;
 194                 head++;
 195         } while (1);
 196
 197         s->inflight -= reaped;
 198         *ring->head = head;
 199         barrier();
 200         return reaped;
 201 }
 202
 203 static void *submitter_fn(void *data)
 204 {
 205         struct submitter *s = data;
 206         int fd, ret, prepped, flags;
 207
 208         printf("submitter=%d\n", gettid());
 209
 210         flags = O_RDONLY;
 211         if (!buffered)
 212                 flags |= O_DIRECT;
 213         fd = open(s->filename, flags);
 214         if (fd < 0) {
 215                 perror("open");
 216                 goto done;
 217         }
 218
 219         if (get_file_size(fd, &s->max_blocks)) {
 220                 printf("failed getting size of device/file\n");
 221                 goto err;
 222         }
 223         if (s->max_blocks <= 1) {
 224                 printf("Zero file/device size?\n");
 225                 goto err;
 226         }
 227         s->max_blocks--;
 228
 229         srand48_r(pthread_self(), &s->rand);
 230
 231         prepped = 0;
 232         do {
 233                 int to_wait, to_submit, this_reap, to_prep;
 234
 235                 if (!prepped && s->inflight < DEPTH) {
 236                         to_prep = min(DEPTH - s->inflight, BATCH_SUBMIT);
 237                         prepped = prep_more_ios(s, fd, to_prep);
 238                 }
 239                 s->inflight += prepped;
 240 submit_more:
 241                 to_submit = prepped;
 242 submit:
 243                 if (s->inflight + BATCH_SUBMIT < DEPTH)
 244                         to_wait = 0;
 245                 else
 246                         to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
 247
 248                 ret = io_uring_enter(s, to_submit, to_wait,
 249                                         IORING_ENTER_GETEVENTS);
 250                 s->calls++;
 251
 252                 this_reap = reap_events(s);
 253                 if (this_reap == -1)
 254                         break;
 255                 s->reaps += this_reap;
 256
 257                 if (ret >= 0) {
 258                         if (!ret) {
 259                                 to_submit = 0;
 260                                 if (s->inflight)
 261                                         goto submit;
 262                                 continue;
 263                         } else if (ret < to_submit) {
 264                                 int diff = to_submit - ret;
 265
 266                                 s->done += ret;
 267                                 prepped -= diff;
 268                                 goto submit_more;
 269                         }
 270                         s->done += ret;
 271                         prepped = 0;
 272                         continue;
 273                 } else if (ret < 0) {
 274                         if (errno == EAGAIN) {
 275                                 if (s->finish)
 276                                         break;
 277                                 if (this_reap)
 278                                         goto submit;
 279                                 to_submit = 0;
 280                                 goto submit;
 281                         }
 282                         printf("io_submit: %s\n", strerror(errno));
 283                         break;
 284                 }
 285         } while (!s->finish);
 286 err:
 287         close(fd);
 288 done:
 289         finish = 1;
 290         return NULL;
 291 }
 292
 293 static void sig_int(int sig)
 294 {
 295         printf("Exiting on signal %d\n", sig);
 296         submitters[0].finish = 1;
 297         finish = 1;
 298 }
 299
 300 static void arm_sig_int(void)
 301 {
 302         struct sigaction act;
 303
 304         memset(&act, 0, sizeof(act));
 305         act.sa_handler = sig_int;
 306         act.sa_flags = SA_RESTART;
 307         sigaction(SIGINT, &act, NULL);
 308 }
 309
 310 static int setup_ring(struct submitter *s)
 311 {
 312         struct io_sq_ring *sring = &s->sq_ring;
 313         struct io_cq_ring *cring = &s->cq_ring;
 314         struct io_uring_params p;
 315         void *ptr;
 316         int fd;
 317
 318         memset(&p, 0, sizeof(p));
 319
 320         if (polled)
 321                 p.flags |= IORING_SETUP_IOPOLL;
 322         if (fixedbufs)
 323                 p.flags |= IORING_SETUP_FIXEDBUFS;
 324         if (buffered)
 325                 p.flags |= IORING_SETUP_SQWQ;
 326         else if (sq_thread) {
 327                 p.flags |= IORING_SETUP_SQTHREAD;
 328                 p.sq_thread_cpu = sq_thread_cpu;
 329         }
 330
 331         if (fixedbufs)
 332                 fd = io_uring_setup(DEPTH, s->iovecs, &p);
 333         else
 334                 fd = io_uring_setup(DEPTH, NULL, &p);
 335         if (fd < 0) {
 336                 perror("io_uring_setup");
 337                 return 1;
 338         }
 339
 340         s->ring_fd = fd;
 341         ptr = mmap(0, p.sq_off.array + p.sq_entries * sizeof(__u32),
 342                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 343                         IORING_OFF_SQ_RING);
 344         printf("sq_ring ptr = 0x%p\n", ptr);
 345         sring->head = ptr + p.sq_off.head;
 346         sring->tail = ptr + p.sq_off.tail;
 347         sring->ring_mask = ptr + p.sq_off.ring_mask;
 348         sring->ring_entries = ptr + p.sq_off.ring_entries;
 349         sring->array = ptr + p.sq_off.array;
 350         sq_ring_mask = *sring->ring_mask;
 351
 352         s->iocbs = mmap(0, p.sq_entries * sizeof(struct io_uring_iocb),
 353                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 354                         IORING_OFF_IOCB);
 355         printf("iocbs ptr   = 0x%p\n", s->iocbs);
 356
 357         ptr = mmap(0, p.cq_off.events + p.cq_entries * sizeof(struct io_uring_event),
 358                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 359                         IORING_OFF_CQ_RING);
 360         printf("cq_ring ptr = 0x%p\n", ptr);
 361         cring->head = ptr + p.cq_off.head;
 362         cring->tail = ptr + p.cq_off.tail;
 363         cring->ring_mask = ptr + p.cq_off.ring_mask;
 364         cring->ring_entries = ptr + p.cq_off.ring_entries;
 365         cring->events = ptr + p.cq_off.events;
 366         cq_ring_mask = *cring->ring_mask;
 367         return 0;
 368 }
 369
 370 int main(int argc, char *argv[])
 371 {
 372         struct submitter *s = &submitters[0];
 373         unsigned long done, calls, reap, cache_hit, cache_miss;
 374         int err, i;
 375         struct rlimit rlim;
 376         void *ret;
 377
 378         if (argc < 2) {
 379                 printf("%s: filename\n", argv[0]);
 380                 return 1;
 381         }
 382
 383         rlim.rlim_cur = RLIM_INFINITY;
 384         rlim.rlim_max = RLIM_INFINITY;
 385         if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
 386                 perror("setrlimit");
 387                 return 1;
 388         }
 389
 390         arm_sig_int();
 391
 392         for (i = 0; i < DEPTH; i++) {
 393                 void *buf;
 394
 395                 if (posix_memalign(&buf, BS, BS)) {
 396                         printf("failed alloc\n");
 397                         return 1;
 398                 }
 399                 s->iovecs[i].iov_base = buf;
 400                 s->iovecs[i].iov_len = BS;
 401         }
 402
 403         err = setup_ring(s);
 404         if (err) {
 405                 printf("ring setup failed: %s, %d\n", strerror(errno), err);
 406                 return 1;
 407         }
 408         printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
 409         printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
 410         strcpy(s->filename, argv[1]);
 411
 412         pthread_create(&s->thread, NULL, submitter_fn, s);
 413
 414         cache_hit = cache_miss = reap = calls = done = 0;
 415         do {
 416                 unsigned long this_done = 0;
 417                 unsigned long this_reap = 0;
 418                 unsigned long this_call = 0;
 419                 unsigned long this_cache_hit = 0;
 420                 unsigned long this_cache_miss = 0;
 421                 unsigned long rpc = 0, ipc = 0;
 422                 double hit = 0.0;
 423
 424                 sleep(1);
 425                 this_done += s->done;
 426                 this_call += s->calls;
 427                 this_reap += s->reaps;
 428                 this_cache_hit += s->cachehit;
 429                 this_cache_miss += s->cachemiss;
 430                 if (this_cache_hit && this_cache_miss) {
 431                         unsigned long hits, total;
 432
 433                         hits = this_cache_hit - cache_hit;
 434                         total = hits + this_cache_miss - cache_miss;
 435                         hit = (double) hits / (double) total;
 436                         hit *= 100.0;
 437                 }
 438                 if (this_call - calls) {
 439                         rpc = (this_done - done) / (this_call - calls);
 440                         ipc = (this_reap - reap) / (this_call - calls);
 441                 }
 442                 printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%u tail=%u), Cachehit=%0.2f%%\n",
 443                                 this_done - done, rpc, ipc, s->inflight,
 444                                 *s->cq_ring.head, *s->cq_ring.tail, hit);
 445                 done = this_done;
 446                 calls = this_call;
 447                 reap = this_reap;
 448                 cache_hit = s->cachehit;
 449                 cache_miss = s->cachemiss;
 450         } while (!finish);
 451
 452         pthread_join(s->thread, &ret);
 453         close(s->ring_fd);
 454         return 0;
 455 }