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
  25 typedef uint64_t u64;
  26 typedef uint32_t u32;
  27 typedef int32_t s32;
  28 typedef uint16_t u16;
  29 typedef uint8_t u8;
  30
  31 #include "../os/io_uring.h"
  32
  33 #define barrier()       __asm__ __volatile__("": : :"memory")
  34
  35 #define min(a, b)               ((a < b) ? (a) : (b))
  36
  37 struct io_sq_ring {
  38         u32 *head;
  39         u32 *tail;
  40         u32 *ring_mask;
  41         u32 *ring_entries;
  42         u32 *array;
  43 };
  44
  45 struct io_cq_ring {
  46         u32 *head;
  47         u32 *tail;
  48         u32 *ring_mask;
  49         u32 *ring_entries;
  50         struct io_uring_event *events;
  51 };
  52
  53 #define DEPTH                   32
  54
  55 #define BATCH_SUBMIT            8
  56 #define BATCH_COMPLETE          8
  57
  58 #define BS                      4096
  59
  60 static unsigned sq_ring_mask, cq_ring_mask;
  61
  62 struct submitter {
  63         pthread_t thread;
  64         unsigned long max_blocks;
  65         int ring_fd;
  66         struct drand48_data rand;
  67         struct io_sq_ring sq_ring;
  68         struct io_uring_iocb *iocbs;
  69         struct iovec iovecs[DEPTH];
  70         struct io_cq_ring cq_ring;
  71         int inflight;
  72         unsigned long reaps;
  73         unsigned long done;
  74         unsigned long calls;
  75         unsigned long cachehit, cachemiss;
  76         volatile int finish;
  77         char filename[128];
  78 };
  79
  80 static struct submitter submitters[1];
  81 static volatile int finish;
  82
  83 static int polled = 0;          /* use IO polling */
  84 static int fixedbufs = 0;       /* use fixed user buffers */
  85 static int buffered = 1;        /* use buffered IO, not O_DIRECT */
  86 static int sq_thread = 0;       /* use kernel submission thread */
  87 static int sq_thread_cpu = 0;   /* pin above thread to this CPU */
  88
  89 static int io_uring_setup(unsigned entries, struct iovec *iovecs,
  90                           struct io_uring_params *p)
  91 {
  92         return syscall(__NR_sys_io_uring_setup, entries, iovecs, p);
  93 }
  94
  95 static int io_uring_enter(struct submitter *s, unsigned int to_submit,
  96                           unsigned int min_complete, unsigned int flags)
  97 {
  98         return syscall(__NR_sys_io_uring_enter, s->ring_fd, to_submit,
  99                         min_complete, flags);
 100 }
 101
 102 static int gettid(void)
 103 {
 104         return syscall(__NR_gettid);
 105 }
 106
 107 static void init_io(struct submitter *s, int fd, unsigned index)
 108 {
 109         struct io_uring_iocb *iocb = &s->iocbs[index];
 110         unsigned long offset;
 111         long r;
 112
 113         lrand48_r(&s->rand, &r);
 114         offset = (r % (s->max_blocks - 1)) * BS;
 115
 116         iocb->opcode = IORING_OP_READ;
 117         iocb->flags = 0;
 118         iocb->ioprio = 0;
 119         iocb->fd = fd;
 120         iocb->off = offset;
 121         iocb->addr = s->iovecs[index].iov_base;
 122         iocb->len = BS;
 123 }
 124
 125 static int prep_more_ios(struct submitter *s, int fd, int max_ios)
 126 {
 127         struct io_sq_ring *ring = &s->sq_ring;
 128         u32 index, tail, next_tail, prepped = 0;
 129
 130         next_tail = tail = *ring->tail;
 131         do {
 132                 next_tail++;
 133                 barrier();
 134                 if (next_tail == *ring->head)
 135                         break;
 136
 137                 index = tail & sq_ring_mask;
 138                 init_io(s, fd, index);
 139                 ring->array[index] = index;
 140                 prepped++;
 141                 tail = next_tail;
 142         } while (prepped < max_ios);
 143
 144         if (*ring->tail != tail) {
 145                 /* order tail store with writes to iocbs above */
 146                 barrier();
 147                 *ring->tail = tail;
 148                 barrier();
 149         }
 150         return prepped;
 151 }
 152
 153 static int get_file_size(int fd, unsigned long *blocks)
 154 {
 155         struct stat st;
 156
 157         if (fstat(fd, &st) < 0)
 158                 return -1;
 159         if (S_ISBLK(st.st_mode)) {
 160                 unsigned long long bytes;
 161
 162                 if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
 163                         return -1;
 164
 165                 *blocks = bytes / BS;
 166                 return 0;
 167         } else if (S_ISREG(st.st_mode)) {
 168                 *blocks = st.st_size / BS;
 169                 return 0;
 170         }
 171
 172         return -1;
 173 }
 174
 175 static int reap_events(struct submitter *s)
 176 {
 177         struct io_cq_ring *ring = &s->cq_ring;
 178         struct io_uring_event *ev;
 179         u32 head, reaped = 0;
 180
 181         head = *ring->head;
 182         do {
 183                 barrier();
 184                 if (head == *ring->tail)
 185                         break;
 186                 ev = &ring->events[head & cq_ring_mask];
 187                 if (ev->res != BS) {
 188                         struct io_uring_iocb *iocb = &s->iocbs[ev->index];
 189
 190                         printf("io: unexpected ret=%d\n", ev->res);
 191                         printf("offset=%lu, size=%lu\n",
 192                                         (unsigned long) iocb->off,
 193                                         (unsigned long) iocb->len);
 194                         return -1;
 195                 }
 196                 if (ev->flags & IOEV_FLAG_CACHEHIT)
 197                         s->cachehit++;
 198                 else
 199                         s->cachemiss++;
 200                 reaped++;
 201                 head++;
 202         } while (1);
 203
 204         s->inflight -= reaped;
 205         *ring->head = head;
 206         barrier();
 207         return reaped;
 208 }
 209
 210 static void *submitter_fn(void *data)
 211 {
 212         struct submitter *s = data;
 213         int fd, ret, prepped, flags;
 214
 215         printf("submitter=%d\n", gettid());
 216
 217         flags = O_RDONLY;
 218         if (!buffered)
 219                 flags |= O_DIRECT;
 220         fd = open(s->filename, flags);
 221         if (fd < 0) {
 222                 perror("open");
 223                 goto done;
 224         }
 225
 226         if (get_file_size(fd, &s->max_blocks)) {
 227                 printf("failed getting size of device/file\n");
 228                 goto err;
 229         }
 230         if (s->max_blocks <= 1) {
 231                 printf("Zero file/device size?\n");
 232                 goto err;
 233         }
 234         s->max_blocks--;
 235
 236         srand48_r(pthread_self(), &s->rand);
 237
 238         prepped = 0;
 239         do {
 240                 int to_wait, to_submit, this_reap, to_prep;
 241
 242                 if (!prepped && s->inflight < DEPTH) {
 243                         to_prep = min(DEPTH - s->inflight, BATCH_SUBMIT);
 244                         prepped = prep_more_ios(s, fd, to_prep);
 245                 }
 246                 s->inflight += prepped;
 247 submit_more:
 248                 to_submit = prepped;
 249 submit:
 250                 if (s->inflight + BATCH_SUBMIT < DEPTH)
 251                         to_wait = 0;
 252                 else
 253                         to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
 254
 255                 ret = io_uring_enter(s, to_submit, to_wait,
 256                                         IORING_ENTER_GETEVENTS);
 257                 s->calls++;
 258
 259                 this_reap = reap_events(s);
 260                 if (this_reap == -1)
 261                         break;
 262                 s->reaps += this_reap;
 263
 264                 if (ret >= 0) {
 265                         if (!ret) {
 266                                 to_submit = 0;
 267                                 if (s->inflight)
 268                                         goto submit;
 269                                 continue;
 270                         } else if (ret < to_submit) {
 271                                 int diff = to_submit - ret;
 272
 273                                 s->done += ret;
 274                                 prepped -= diff;
 275                                 goto submit_more;
 276                         }
 277                         s->done += ret;
 278                         prepped = 0;
 279                         continue;
 280                 } else if (ret < 0) {
 281                         if (errno == EAGAIN) {
 282                                 if (s->finish)
 283                                         break;
 284                                 if (this_reap)
 285                                         goto submit;
 286                                 to_submit = 0;
 287                                 goto submit;
 288                         }
 289                         printf("io_submit: %s\n", strerror(errno));
 290                         break;
 291                 }
 292         } while (!s->finish);
 293 err:
 294         close(fd);
 295 done:
 296         finish = 1;
 297         return NULL;
 298 }
 299
 300 static void sig_int(int sig)
 301 {
 302         printf("Exiting on signal %d\n", sig);
 303         submitters[0].finish = 1;
 304         finish = 1;
 305 }
 306
 307 static void arm_sig_int(void)
 308 {
 309         struct sigaction act;
 310
 311         memset(&act, 0, sizeof(act));
 312         act.sa_handler = sig_int;
 313         act.sa_flags = SA_RESTART;
 314         sigaction(SIGINT, &act, NULL);
 315 }
 316
 317 static int setup_ring(struct submitter *s)
 318 {
 319         struct io_sq_ring *sring = &s->sq_ring;
 320         struct io_cq_ring *cring = &s->cq_ring;
 321         struct io_uring_params p;
 322         void *ptr;
 323         int fd;
 324
 325         memset(&p, 0, sizeof(p));
 326
 327         if (polled)
 328                 p.flags |= IORING_SETUP_IOPOLL;
 329         if (fixedbufs)
 330                 p.flags |= IORING_SETUP_FIXEDBUFS;
 331         if (buffered)
 332                 p.flags |= IORING_SETUP_SQWQ;
 333         else if (sq_thread) {
 334                 p.flags |= IORING_SETUP_SQTHREAD;
 335                 p.sq_thread_cpu = sq_thread_cpu;
 336         }
 337
 338         if (fixedbufs)
 339                 fd = io_uring_setup(DEPTH, s->iovecs, &p);
 340         else
 341                 fd = io_uring_setup(DEPTH, NULL, &p);
 342         if (fd < 0) {
 343                 perror("io_uring_setup");
 344                 return 1;
 345         }
 346
 347         s->ring_fd = fd;
 348         ptr = mmap(0, p.sq_off.array + p.sq_entries * sizeof(u32),
 349                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 350                         IORING_OFF_SQ_RING);
 351         printf("sq_ring ptr = 0x%p\n", ptr);
 352         sring->head = ptr + p.sq_off.head;
 353         sring->tail = ptr + p.sq_off.tail;
 354         sring->ring_mask = ptr + p.sq_off.ring_mask;
 355         sring->ring_entries = ptr + p.sq_off.ring_entries;
 356         sring->array = ptr + p.sq_off.array;
 357         sq_ring_mask = *sring->ring_mask;
 358
 359         s->iocbs = mmap(0, p.sq_entries * sizeof(struct io_uring_iocb),
 360                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 361                         IORING_OFF_IOCB);
 362         printf("iocbs ptr   = 0x%p\n", s->iocbs);
 363
 364         ptr = mmap(0, p.cq_off.events + p.cq_entries * sizeof(struct io_uring_event),
 365                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 366                         IORING_OFF_CQ_RING);
 367         printf("cq_ring ptr = 0x%p\n", ptr);
 368         cring->head = ptr + p.cq_off.head;
 369         cring->tail = ptr + p.cq_off.tail;
 370         cring->ring_mask = ptr + p.cq_off.ring_mask;
 371         cring->ring_entries = ptr + p.cq_off.ring_entries;
 372         cring->events = ptr + p.cq_off.events;
 373         cq_ring_mask = *cring->ring_mask;
 374         return 0;
 375 }
 376
 377 int main(int argc, char *argv[])
 378 {
 379         struct submitter *s = &submitters[0];
 380         unsigned long done, calls, reap, cache_hit, cache_miss;
 381         int err, i;
 382         struct rlimit rlim;
 383         void *ret;
 384
 385         if (argc < 2) {
 386                 printf("%s: filename\n", argv[0]);
 387                 return 1;
 388         }
 389
 390         rlim.rlim_cur = RLIM_INFINITY;
 391         rlim.rlim_max = RLIM_INFINITY;
 392         if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
 393                 perror("setrlimit");
 394                 return 1;
 395         }
 396
 397         arm_sig_int();
 398
 399         for (i = 0; i < DEPTH; i++) {
 400                 void *buf;
 401
 402                 if (posix_memalign(&buf, BS, BS)) {
 403                         printf("failed alloc\n");
 404                         return 1;
 405                 }
 406                 s->iovecs[i].iov_base = buf;
 407                 s->iovecs[i].iov_len = BS;
 408         }
 409
 410         err = setup_ring(s);
 411         if (err) {
 412                 printf("ring setup failed: %s, %d\n", strerror(errno), err);
 413                 return 1;
 414         }
 415         printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
 416         printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
 417         strcpy(s->filename, argv[1]);
 418
 419         pthread_create(&s->thread, NULL, submitter_fn, s);
 420
 421         cache_hit = cache_miss = reap = calls = done = 0;
 422         do {
 423                 unsigned long this_done = 0;
 424                 unsigned long this_reap = 0;
 425                 unsigned long this_call = 0;
 426                 unsigned long this_cache_hit = 0;
 427                 unsigned long this_cache_miss = 0;
 428                 unsigned long rpc = 0, ipc = 0;
 429                 double hit = 0.0;
 430
 431                 sleep(1);
 432                 this_done += s->done;
 433                 this_call += s->calls;
 434                 this_reap += s->reaps;
 435                 this_cache_hit += s->cachehit;
 436                 this_cache_miss += s->cachemiss;
 437                 if (this_cache_hit && this_cache_miss) {
 438                         unsigned long hits, total;
 439
 440                         hits = this_cache_hit - cache_hit;
 441                         total = hits + this_cache_miss - cache_miss;
 442                         hit = (double) hits / (double) total;
 443                         hit *= 100.0;
 444                 }
 445                 if (this_call - calls) {
 446                         rpc = (this_done - done) / (this_call - calls);
 447                         ipc = (this_reap - reap) / (this_call - calls);
 448                 }
 449                 printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%u tail=%u), Cachehit=%0.2f%%\n",
 450                                 this_done - done, rpc, ipc, s->inflight,
 451                                 *s->cq_ring.head, *s->cq_ring.tail, hit);
 452                 done = this_done;
 453                 calls = this_call;
 454                 reap = this_reap;
 455                 cache_hit = s->cachehit;
 456                 cache_miss = s->cachemiss;
 457         } while (!finish);
 458
 459         pthread_join(s->thread, &ret);
 460         close(s->ring_fd);
 461         return 0;
 462 }