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_cqe *cqes;
  45 };
  46
  47 #define DEPTH                   32
  48
  49 #define BATCH_SUBMIT            8
  50 #define BATCH_COMPLETE          8
  51
  52 #define BS                      4096
  53
  54 #define MAX_FDS                 16
  55
  56 static unsigned sq_ring_mask, cq_ring_mask;
  57
  58 struct file {
  59         unsigned long max_blocks;
  60         int fd;
  61 };
  62
  63 struct submitter {
  64         pthread_t thread;
  65         int ring_fd;
  66         struct drand48_data rand;
  67         struct io_sq_ring sq_ring;
  68         struct io_uring_sqe *sqes;
  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         struct file files[MAX_FDS];
  78         unsigned nr_files;
  79         unsigned cur_file;
  80 };
  81
  82 static struct submitter submitters[1];
  83 static volatile int finish;
  84
  85 static int polled = 1;          /* use IO polling */
  86 static int fixedbufs = 0;       /* use fixed user buffers */
  87 static int buffered = 0;        /* use buffered IO, not O_DIRECT */
  88 static int sq_thread_poll = 0;  /* use kernel submission/poller thread */
  89 static int sq_thread_cpu = -1;  /* pin above thread to this CPU */
  90
  91 static int io_uring_register_buffers(struct submitter *s)
  92 {
  93         struct io_uring_register_buffers reg = {
  94                 .iovecs = s->iovecs,
  95                 .nr_iovecs = DEPTH
  96         };
  97
  98         return syscall(__NR_sys_io_uring_register, s->ring_fd,
  99                         IORING_REGISTER_BUFFERS, &reg);
 100 }
 101
 102 static int io_uring_setup(unsigned entries, struct io_uring_params *p)
 103 {
 104         return syscall(__NR_sys_io_uring_setup, entries, p);
 105 }
 106
 107 static int io_uring_enter(struct submitter *s, unsigned int to_submit,
 108                           unsigned int min_complete, unsigned int flags)
 109 {
 110         return syscall(__NR_sys_io_uring_enter, s->ring_fd, to_submit,
 111                         min_complete, flags);
 112 }
 113
 114 static int gettid(void)
 115 {
 116         return syscall(__NR_gettid);
 117 }
 118
 119 static void init_io(struct submitter *s, unsigned index)
 120 {
 121         struct io_uring_sqe *sqe = &s->sqes[index];
 122         unsigned long offset;
 123         struct file *f;
 124         long r;
 125
 126         f = &s->files[s->cur_file];
 127         s->cur_file++;
 128         if (s->cur_file == s->nr_files)
 129                 s->cur_file = 0;
 130
 131         lrand48_r(&s->rand, &r);
 132         offset = (r % (f->max_blocks - 1)) * BS;
 133
 134         sqe->flags = 0;
 135         sqe->opcode = IORING_OP_READV;
 136         if (fixedbufs) {
 137                 sqe->addr = s->iovecs[index].iov_base;
 138                 sqe->len = BS;
 139                 sqe->buf_index = index;
 140                 sqe->flags |= IOSQE_FIXED_BUFFER;
 141         } else {
 142                 sqe->addr = &s->iovecs[index];
 143                 sqe->len = 1;
 144                 sqe->buf_index = 0;
 145         }
 146         sqe->ioprio = 0;
 147         sqe->fd = f->fd;
 148         sqe->off = offset;
 149 }
 150
 151 static int prep_more_ios(struct submitter *s, int max_ios)
 152 {
 153         struct io_sq_ring *ring = &s->sq_ring;
 154         unsigned index, tail, next_tail, prepped = 0;
 155
 156         next_tail = tail = *ring->tail;
 157         do {
 158                 next_tail++;
 159                 barrier();
 160                 if (next_tail == *ring->head)
 161                         break;
 162
 163                 index = tail & sq_ring_mask;
 164                 init_io(s, index);
 165                 ring->array[index] = index;
 166                 prepped++;
 167                 tail = next_tail;
 168         } while (prepped < max_ios);
 169
 170         if (*ring->tail != tail) {
 171                 /* order tail store with writes to sqes above */
 172                 barrier();
 173                 *ring->tail = tail;
 174                 barrier();
 175         }
 176         return prepped;
 177 }
 178
 179 static int get_file_size(struct file *f)
 180 {
 181         struct stat st;
 182
 183         if (fstat(f->fd, &st) < 0)
 184                 return -1;
 185         if (S_ISBLK(st.st_mode)) {
 186                 unsigned long long bytes;
 187
 188                 if (ioctl(f->fd, BLKGETSIZE64, &bytes) != 0)
 189                         return -1;
 190
 191                 f->max_blocks = bytes / BS;
 192                 return 0;
 193         } else if (S_ISREG(st.st_mode)) {
 194                 f->max_blocks = st.st_size / BS;
 195                 return 0;
 196         }
 197
 198         return -1;
 199 }
 200
 201 static int reap_events(struct submitter *s)
 202 {
 203         struct io_cq_ring *ring = &s->cq_ring;
 204         struct io_uring_cqe *cqe;
 205         unsigned head, reaped = 0;
 206
 207         head = *ring->head;
 208         do {
 209                 barrier();
 210                 if (head == *ring->tail)
 211                         break;
 212                 cqe = &ring->cqes[head & cq_ring_mask];
 213                 if (cqe->res != BS) {
 214                         printf("io: unexpected ret=%d\n", cqe->res);
 215                         return -1;
 216                 }
 217                 if (cqe->flags & IOCQE_FLAG_CACHEHIT)
 218                         s->cachehit++;
 219                 else
 220                         s->cachemiss++;
 221                 reaped++;
 222                 head++;
 223         } while (1);
 224
 225         s->inflight -= reaped;
 226         *ring->head = head;
 227         barrier();
 228         return reaped;
 229 }
 230
 231 static void *submitter_fn(void *data)
 232 {
 233         struct submitter *s = data;
 234         int ret, prepped;
 235
 236         printf("submitter=%d\n", gettid());
 237
 238         srand48_r(pthread_self(), &s->rand);
 239
 240         prepped = 0;
 241         do {
 242                 int to_wait, to_submit, this_reap, to_prep;
 243
 244                 if (!prepped && s->inflight < DEPTH) {
 245                         to_prep = min(DEPTH - s->inflight, BATCH_SUBMIT);
 246                         prepped = prep_more_ios(s, to_prep);
 247                 }
 248                 s->inflight += prepped;
 249 submit_more:
 250                 to_submit = prepped;
 251 submit:
 252                 if (s->inflight + BATCH_SUBMIT < DEPTH)
 253                         to_wait = 0;
 254                 else
 255                         to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
 256
 257                 ret = io_uring_enter(s, to_submit, to_wait,
 258                                         IORING_ENTER_GETEVENTS);
 259                 s->calls++;
 260
 261                 this_reap = reap_events(s);
 262                 if (this_reap == -1)
 263                         break;
 264                 s->reaps += this_reap;
 265
 266                 if (ret >= 0) {
 267                         if (!ret) {
 268                                 to_submit = 0;
 269                                 if (s->inflight)
 270                                         goto submit;
 271                                 continue;
 272                         } else if (ret < to_submit) {
 273                                 int diff = to_submit - ret;
 274
 275                                 s->done += ret;
 276                                 prepped -= diff;
 277                                 goto submit_more;
 278                         }
 279                         s->done += ret;
 280                         prepped = 0;
 281                         continue;
 282                 } else if (ret < 0) {
 283                         if (errno == EAGAIN) {
 284                                 if (s->finish)
 285                                         break;
 286                                 if (this_reap)
 287                                         goto submit;
 288                                 to_submit = 0;
 289                                 goto submit;
 290                         }
 291                         printf("io_submit: %s\n", strerror(errno));
 292                         break;
 293                 }
 294         } while (!s->finish);
 295
 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         int ret, fd;
 323         void *ptr;
 324
 325         memset(&p, 0, sizeof(p));
 326
 327         if (sq_thread_poll) {
 328                 p.flags |= IORING_SETUP_SQPOLL;
 329                 if (sq_thread_cpu != -1)
 330                         p.flags |= IORING_SETUP_SQ_AFF;
 331         }
 332
 333         fd = io_uring_setup(DEPTH, &p);
 334         if (fd < 0) {
 335                 perror("io_uring_setup");
 336                 return 1;
 337         }
 338         s->ring_fd = fd;
 339
 340         if (fixedbufs) {
 341                 ret = io_uring_register_buffers(s);
 342                 if (ret < 0) {
 343                         perror("io_uring_register");
 344                         return 1;
 345                 }
 346         }
 347
 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->sqes = mmap(0, p.sq_entries * sizeof(struct io_uring_sqe),
 360                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 361                         IORING_OFF_SQES);
 362         printf("sqes ptr    = 0x%p\n", s->sqes);
 363
 364         ptr = mmap(0, p.cq_off.cqes + p.cq_entries * sizeof(struct io_uring_cqe),
 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->cqes = ptr + p.cq_off.cqes;
 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, flags, fd;
 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         flags = O_RDONLY;
 391         if (!buffered)
 392                 flags |= O_DIRECT;
 393
 394         i = 1;
 395         while (i < argc) {
 396                 struct file *f = &s->files[s->nr_files];
 397
 398                 fd = open(argv[i], flags);
 399                 if (fd < 0) {
 400                         perror("open");
 401                         return 1;
 402                 }
 403                 f->fd = fd;
 404                 if (get_file_size(f)) {
 405                         printf("failed getting size of device/file\n");
 406                         return 1;
 407                 }
 408                 if (f->max_blocks <= 1) {
 409                         printf("Zero file/device size?\n");
 410                         return 1;
 411                 }
 412                 f->max_blocks--;
 413
 414                 printf("Added file %s\n", argv[i]);
 415                 s->nr_files++;
 416                 i++;
 417         }
 418
 419         rlim.rlim_cur = RLIM_INFINITY;
 420         rlim.rlim_max = RLIM_INFINITY;
 421         if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
 422                 perror("setrlimit");
 423                 return 1;
 424         }
 425
 426         arm_sig_int();
 427
 428         for (i = 0; i < DEPTH; i++) {
 429                 void *buf;
 430
 431                 if (posix_memalign(&buf, BS, BS)) {
 432                         printf("failed alloc\n");
 433                         return 1;
 434                 }
 435                 s->iovecs[i].iov_base = buf;
 436                 s->iovecs[i].iov_len = BS;
 437         }
 438
 439         err = setup_ring(s);
 440         if (err) {
 441                 printf("ring setup failed: %s, %d\n", strerror(errno), err);
 442                 return 1;
 443         }
 444         printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
 445         printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
 446
 447         pthread_create(&s->thread, NULL, submitter_fn, s);
 448
 449         cache_hit = cache_miss = reap = calls = done = 0;
 450         do {
 451                 unsigned long this_done = 0;
 452                 unsigned long this_reap = 0;
 453                 unsigned long this_call = 0;
 454                 unsigned long this_cache_hit = 0;
 455                 unsigned long this_cache_miss = 0;
 456                 unsigned long rpc = 0, ipc = 0;
 457                 double hit = 0.0;
 458
 459                 sleep(1);
 460                 this_done += s->done;
 461                 this_call += s->calls;
 462                 this_reap += s->reaps;
 463                 this_cache_hit += s->cachehit;
 464                 this_cache_miss += s->cachemiss;
 465                 if (this_cache_hit && this_cache_miss) {
 466                         unsigned long hits, total;
 467
 468                         hits = this_cache_hit - cache_hit;
 469                         total = hits + this_cache_miss - cache_miss;
 470                         hit = (double) hits / (double) total;
 471                         hit *= 100.0;
 472                 }
 473                 if (this_call - calls) {
 474                         rpc = (this_done - done) / (this_call - calls);
 475                         ipc = (this_reap - reap) / (this_call - calls);
 476                 }
 477                 printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%u tail=%u), Cachehit=%0.2f%%\n",
 478                                 this_done - done, rpc, ipc, s->inflight,
 479                                 *s->cq_ring.head, *s->cq_ring.tail, hit);
 480                 done = this_done;
 481                 calls = this_call;
 482                 reap = this_reap;
 483                 cache_hit = s->cachehit;
 484                 cache_miss = s->cachemiss;
 485         } while (!finish);
 486
 487         pthread_join(s->thread, &ret);
 488         close(s->ring_fd);
 489         return 0;
 490 }