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 "../lib/types.h"
  25 #include "../os/io_uring.h"
  26
  27 #define barrier()       __asm__ __volatile__("": : :"memory")
  28
  29 #define min(a, b)               ((a < b) ? (a) : (b))
  30
  31 struct io_sq_ring {
  32         unsigned *head;
  33         unsigned *tail;
  34         unsigned *ring_mask;
  35         unsigned *ring_entries;
  36         unsigned *array;
  37 };
  38
  39 struct io_cq_ring {
  40         unsigned *head;
  41         unsigned *tail;
  42         unsigned *ring_mask;
  43         unsigned *ring_entries;
  44         struct io_uring_event *events;
  45 };
  46
  47 #define DEPTH                   32
  48
  49 #define BATCH_SUBMIT            8
  50 #define BATCH_COMPLETE          8
  51
  52 #define BS                      4096
  53
  54 static unsigned sq_ring_mask, cq_ring_mask;
  55
  56 struct submitter {
  57         pthread_t thread;
  58         unsigned long max_blocks;
  59         int ring_fd;
  60         struct drand48_data rand;
  61         struct io_sq_ring sq_ring;
  62         struct io_uring_iocb *iocbs;
  63         struct iovec iovecs[DEPTH];
  64         struct io_cq_ring cq_ring;
  65         int inflight;
  66         unsigned long reaps;
  67         unsigned long done;
  68         unsigned long calls;
  69         unsigned long cachehit, cachemiss;
  70         volatile int finish;
  71         char filename[128];
  72 };
  73
  74 static struct submitter submitters[1];
  75 static volatile int finish;
  76
  77 static int polled = 0;          /* use IO polling */
  78 static int fixedbufs = 0;       /* use fixed user buffers */
  79 static int buffered = 1;        /* use buffered IO, not O_DIRECT */
  80 static int sq_thread = 0;       /* use kernel submission thread */
  81 static int sq_thread_cpu = 0;   /* pin above thread to this CPU */
  82
  83 static int io_uring_setup(unsigned entries, struct iovec *iovecs,
  84                           struct io_uring_params *p)
  85 {
  86         return syscall(__NR_sys_io_uring_setup, entries, iovecs, p);
  87 }
  88
  89 static int io_uring_enter(struct submitter *s, unsigned int to_submit,
  90                           unsigned int min_complete, unsigned int flags)
  91 {
  92         return syscall(__NR_sys_io_uring_enter, s->ring_fd, to_submit,
  93                         min_complete, flags);
  94 }
  95
  96 static int gettid(void)
  97 {
  98         return syscall(__NR_gettid);
  99 }
 100
 101 static void init_io(struct submitter *s, int fd, unsigned index)
 102 {
 103         struct io_uring_iocb *iocb = &s->iocbs[index];
 104         unsigned long offset;
 105         long r;
 106
 107         lrand48_r(&s->rand, &r);
 108         offset = (r % (s->max_blocks - 1)) * BS;
 109
 110         iocb->opcode = IORING_OP_READ;
 111         iocb->flags = 0;
 112         iocb->ioprio = 0;
 113         iocb->fd = fd;
 114         iocb->off = offset;
 115         iocb->addr = s->iovecs[index].iov_base;
 116         iocb->len = BS;
 117 }
 118
 119 static int prep_more_ios(struct submitter *s, int fd, int max_ios)
 120 {
 121         struct io_sq_ring *ring = &s->sq_ring;
 122         unsigned index, tail, next_tail, prepped = 0;
 123
 124         next_tail = tail = *ring->tail;
 125         do {
 126                 next_tail++;
 127                 barrier();
 128                 if (next_tail == *ring->head)
 129                         break;
 130
 131                 index = tail & sq_ring_mask;
 132                 init_io(s, fd, index);
 133                 ring->array[index] = index;
 134                 prepped++;
 135                 tail = next_tail;
 136         } while (prepped < max_ios);
 137
 138         if (*ring->tail != tail) {
 139                 /* order tail store with writes to iocbs above */
 140                 barrier();
 141                 *ring->tail = tail;
 142                 barrier();
 143         }
 144         return prepped;
 145 }
 146
 147 static int get_file_size(int fd, unsigned long *blocks)
 148 {
 149         struct stat st;
 150
 151         if (fstat(fd, &st) < 0)
 152                 return -1;
 153         if (S_ISBLK(st.st_mode)) {
 154                 unsigned long long bytes;
 155
 156                 if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
 157                         return -1;
 158
 159                 *blocks = bytes / BS;
 160                 return 0;
 161         } else if (S_ISREG(st.st_mode)) {
 162                 *blocks = st.st_size / BS;
 163                 return 0;
 164         }
 165
 166         return -1;
 167 }
 168
 169 static int reap_events(struct submitter *s)
 170 {
 171         struct io_cq_ring *ring = &s->cq_ring;
 172         struct io_uring_event *ev;
 173         unsigned head, reaped = 0;
 174
 175         head = *ring->head;
 176         do {
 177                 barrier();
 178                 if (head == *ring->tail)
 179                         break;
 180                 ev = &ring->events[head & cq_ring_mask];
 181                 if (ev->res != BS) {
 182                         struct io_uring_iocb *iocb = &s->iocbs[ev->index];
 183
 184                         printf("io: unexpected ret=%d\n", ev->res);
 185                         printf("offset=%lu, size=%lu\n",
 186                                         (unsigned long) iocb->off,
 187                                         (unsigned long) iocb->len);
 188                         return -1;
 189                 }
 190                 if (ev->flags & IOEV_FLAG_CACHEHIT)
 191                         s->cachehit++;
 192                 else
 193                         s->cachemiss++;
 194                 reaped++;
 195                 head++;
 196         } while (1);
 197
 198         s->inflight -= reaped;
 199         *ring->head = head;
 200         barrier();
 201         return reaped;
 202 }
 203
 204 static void *submitter_fn(void *data)
 205 {
 206         struct submitter *s = data;
 207         int fd, ret, prepped, flags;
 208
 209         printf("submitter=%d\n", gettid());
 210
 211         flags = O_RDONLY;
 212         if (!buffered)
 213                 flags |= O_DIRECT;
 214         fd = open(s->filename, flags);
 215         if (fd < 0) {
 216                 perror("open");
 217                 goto done;
 218         }
 219
 220         if (get_file_size(fd, &s->max_blocks)) {
 221                 printf("failed getting size of device/file\n");
 222                 goto err;
 223         }
 224         if (s->max_blocks <= 1) {
 225                 printf("Zero file/device size?\n");
 226                 goto err;
 227         }
 228         s->max_blocks--;
 229
 230         srand48_r(pthread_self(), &s->rand);
 231
 232         prepped = 0;
 233         do {
 234                 int to_wait, to_submit, this_reap, to_prep;
 235
 236                 if (!prepped && s->inflight < DEPTH) {
 237                         to_prep = min(DEPTH - s->inflight, BATCH_SUBMIT);
 238                         prepped = prep_more_ios(s, fd, to_prep);
 239                 }
 240                 s->inflight += prepped;
 241 submit_more:
 242                 to_submit = prepped;
 243 submit:
 244                 if (s->inflight + BATCH_SUBMIT < DEPTH)
 245                         to_wait = 0;
 246                 else
 247                         to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
 248
 249                 ret = io_uring_enter(s, to_submit, to_wait,
 250                                         IORING_ENTER_GETEVENTS);
 251                 s->calls++;
 252
 253                 this_reap = reap_events(s);
 254                 if (this_reap == -1)
 255                         break;
 256                 s->reaps += this_reap;
 257
 258                 if (ret >= 0) {
 259                         if (!ret) {
 260                                 to_submit = 0;
 261                                 if (s->inflight)
 262                                         goto submit;
 263                                 continue;
 264                         } else if (ret < to_submit) {
 265                                 int diff = to_submit - ret;
 266
 267                                 s->done += ret;
 268                                 prepped -= diff;
 269                                 goto submit_more;
 270                         }
 271                         s->done += ret;
 272                         prepped = 0;
 273                         continue;
 274                 } else if (ret < 0) {
 275                         if (errno == EAGAIN) {
 276                                 if (s->finish)
 277                                         break;
 278                                 if (this_reap)
 279                                         goto submit;
 280                                 to_submit = 0;
 281                                 goto submit;
 282                         }
 283                         printf("io_submit: %s\n", strerror(errno));
 284                         break;
 285                 }
 286         } while (!s->finish);
 287 err:
 288         close(fd);
 289 done:
 290         finish = 1;
 291         return NULL;
 292 }
 293
 294 static void sig_int(int sig)
 295 {
 296         printf("Exiting on signal %d\n", sig);
 297         submitters[0].finish = 1;
 298         finish = 1;
 299 }
 300
 301 static void arm_sig_int(void)
 302 {
 303         struct sigaction act;
 304
 305         memset(&act, 0, sizeof(act));
 306         act.sa_handler = sig_int;
 307         act.sa_flags = SA_RESTART;
 308         sigaction(SIGINT, &act, NULL);
 309 }
 310
 311 static int setup_ring(struct submitter *s)
 312 {
 313         struct io_sq_ring *sring = &s->sq_ring;
 314         struct io_cq_ring *cring = &s->cq_ring;
 315         struct io_uring_params p;
 316         void *ptr;
 317         int fd;
 318
 319         memset(&p, 0, sizeof(p));
 320
 321         if (polled)
 322                 p.flags |= IORING_SETUP_IOPOLL;
 323         if (fixedbufs)
 324                 p.flags |= IORING_SETUP_FIXEDBUFS;
 325         if (buffered)
 326                 p.flags |= IORING_SETUP_SQWQ;
 327         else if (sq_thread) {
 328                 p.flags |= IORING_SETUP_SQTHREAD;
 329                 p.sq_thread_cpu = sq_thread_cpu;
 330         }
 331
 332         if (fixedbufs)
 333                 fd = io_uring_setup(DEPTH, s->iovecs, &p);
 334         else
 335                 fd = io_uring_setup(DEPTH, NULL, &p);
 336         if (fd < 0) {
 337                 perror("io_uring_setup");
 338                 return 1;
 339         }
 340
 341         s->ring_fd = fd;
 342         ptr = mmap(0, p.sq_off.array + p.sq_entries * sizeof(__u32),
 343                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 344                         IORING_OFF_SQ_RING);
 345         printf("sq_ring ptr = 0x%p\n", ptr);
 346         sring->head = ptr + p.sq_off.head;
 347         sring->tail = ptr + p.sq_off.tail;
 348         sring->ring_mask = ptr + p.sq_off.ring_mask;
 349         sring->ring_entries = ptr + p.sq_off.ring_entries;
 350         sring->array = ptr + p.sq_off.array;
 351         sq_ring_mask = *sring->ring_mask;
 352
 353         s->iocbs = mmap(0, p.sq_entries * sizeof(struct io_uring_iocb),
 354                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 355                         IORING_OFF_IOCB);
 356         printf("iocbs ptr   = 0x%p\n", s->iocbs);
 357
 358         ptr = mmap(0, p.cq_off.events + p.cq_entries * sizeof(struct io_uring_event),
 359                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 360                         IORING_OFF_CQ_RING);
 361         printf("cq_ring ptr = 0x%p\n", ptr);
 362         cring->head = ptr + p.cq_off.head;
 363         cring->tail = ptr + p.cq_off.tail;
 364         cring->ring_mask = ptr + p.cq_off.ring_mask;
 365         cring->ring_entries = ptr + p.cq_off.ring_entries;
 366         cring->events = ptr + p.cq_off.events;
 367         cq_ring_mask = *cring->ring_mask;
 368         return 0;
 369 }
 370
 371 int main(int argc, char *argv[])
 372 {
 373         struct submitter *s = &submitters[0];
 374         unsigned long done, calls, reap, cache_hit, cache_miss;
 375         int err, i;
 376         struct rlimit rlim;
 377         void *ret;
 378
 379         if (argc < 2) {
 380                 printf("%s: filename\n", argv[0]);
 381                 return 1;
 382         }
 383
 384         rlim.rlim_cur = RLIM_INFINITY;
 385         rlim.rlim_max = RLIM_INFINITY;
 386         if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
 387                 perror("setrlimit");
 388                 return 1;
 389         }
 390
 391         arm_sig_int();
 392
 393         for (i = 0; i < DEPTH; i++) {
 394                 void *buf;
 395
 396                 if (posix_memalign(&buf, BS, BS)) {
 397                         printf("failed alloc\n");
 398                         return 1;
 399                 }
 400                 s->iovecs[i].iov_base = buf;
 401                 s->iovecs[i].iov_len = BS;
 402         }
 403
 404         err = setup_ring(s);
 405         if (err) {
 406                 printf("ring setup failed: %s, %d\n", strerror(errno), err);
 407                 return 1;
 408         }
 409         printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
 410         printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
 411         strcpy(s->filename, argv[1]);
 412
 413         pthread_create(&s->thread, NULL, submitter_fn, s);
 414
 415         cache_hit = cache_miss = reap = calls = done = 0;
 416         do {
 417                 unsigned long this_done = 0;
 418                 unsigned long this_reap = 0;
 419                 unsigned long this_call = 0;
 420                 unsigned long this_cache_hit = 0;
 421                 unsigned long this_cache_miss = 0;
 422                 unsigned long rpc = 0, ipc = 0;
 423                 double hit = 0.0;
 424
 425                 sleep(1);
 426                 this_done += s->done;
 427                 this_call += s->calls;
 428                 this_reap += s->reaps;
 429                 this_cache_hit += s->cachehit;
 430                 this_cache_miss += s->cachemiss;
 431                 if (this_cache_hit && this_cache_miss) {
 432                         unsigned long hits, total;
 433
 434                         hits = this_cache_hit - cache_hit;
 435                         total = hits + this_cache_miss - cache_miss;
 436                         hit = (double) hits / (double) total;
 437                         hit *= 100.0;
 438                 }
 439                 if (this_call - calls) {
 440                         rpc = (this_done - done) / (this_call - calls);
 441                         ipc = (this_reap - reap) / (this_call - calls);
 442                 }
 443                 printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%u tail=%u), Cachehit=%0.2f%%\n",
 444                                 this_done - done, rpc, ipc, s->inflight,
 445                                 *s->cq_ring.head, *s->cq_ring.tail, hit);
 446                 done = this_done;
 447                 calls = this_call;
 448                 reap = this_reap;
 449                 cache_hit = s->cachehit;
 450                 cache_miss = s->cachemiss;
 451         } while (!finish);
 452
 453         pthread_join(s->thread, &ret);
 454         close(s->ring_fd);
 455         return 0;
 456 }