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 = 0;       /* use kernel submission thread */
  89 static int sq_thread_cpu = 0;   /* pin above thread to this CPU */
  90
  91 static int io_uring_setup(unsigned entries, struct iovec *iovecs,
  92                           unsigned nr_iovecs, struct io_uring_params *p)
  93 {
  94         return syscall(__NR_sys_io_uring_setup, entries, iovecs, nr_iovecs, p);
  95 }
  96
  97 static int io_uring_enter(struct submitter *s, unsigned int to_submit,
  98                           unsigned int min_complete, unsigned int flags)
  99 {
 100         return syscall(__NR_sys_io_uring_enter, s->ring_fd, to_submit,
 101                         min_complete, flags);
 102 }
 103
 104 static int gettid(void)
 105 {
 106         return syscall(__NR_gettid);
 107 }
 108
 109 static void init_io(struct submitter *s, unsigned index)
 110 {
 111         struct io_uring_sqe *sqe = &s->sqes[index];
 112         unsigned long offset;
 113         struct file *f;
 114         long r;
 115
 116         f = &s->files[s->cur_file];
 117         s->cur_file++;
 118         if (s->cur_file == s->nr_files)
 119                 s->cur_file = 0;
 120
 121         lrand48_r(&s->rand, &r);
 122         offset = (r % (f->max_blocks - 1)) * BS;
 123
 124         if (fixedbufs) {
 125                 sqe->opcode = IORING_OP_READ_FIXED;
 126                 sqe->addr = s->iovecs[index].iov_base;
 127                 sqe->len = BS;
 128                 sqe->index = index;
 129         } else {
 130                 sqe->opcode = IORING_OP_READV;
 131                 sqe->addr = &s->iovecs[index];
 132                 sqe->len = 1;
 133         }
 134         sqe->flags = 0;
 135         sqe->ioprio = 0;
 136         sqe->fd = f->fd;
 137         sqe->off = offset;
 138 }
 139
 140 static int prep_more_ios(struct submitter *s, int max_ios)
 141 {
 142         struct io_sq_ring *ring = &s->sq_ring;
 143         unsigned index, tail, next_tail, prepped = 0;
 144
 145         next_tail = tail = *ring->tail;
 146         do {
 147                 next_tail++;
 148                 barrier();
 149                 if (next_tail == *ring->head)
 150                         break;
 151
 152                 index = tail & sq_ring_mask;
 153                 init_io(s, index);
 154                 ring->array[index] = index;
 155                 prepped++;
 156                 tail = next_tail;
 157         } while (prepped < max_ios);
 158
 159         if (*ring->tail != tail) {
 160                 /* order tail store with writes to sqes above */
 161                 barrier();
 162                 *ring->tail = tail;
 163                 barrier();
 164         }
 165         return prepped;
 166 }
 167
 168 static int get_file_size(struct file *f)
 169 {
 170         struct stat st;
 171
 172         if (fstat(f->fd, &st) < 0)
 173                 return -1;
 174         if (S_ISBLK(st.st_mode)) {
 175                 unsigned long long bytes;
 176
 177                 if (ioctl(f->fd, BLKGETSIZE64, &bytes) != 0)
 178                         return -1;
 179
 180                 f->max_blocks = bytes / BS;
 181                 return 0;
 182         } else if (S_ISREG(st.st_mode)) {
 183                 f->max_blocks = st.st_size / BS;
 184                 return 0;
 185         }
 186
 187         return -1;
 188 }
 189
 190 static int reap_events(struct submitter *s)
 191 {
 192         struct io_cq_ring *ring = &s->cq_ring;
 193         struct io_uring_cqe *cqe;
 194         unsigned head, reaped = 0;
 195
 196         head = *ring->head;
 197         do {
 198                 barrier();
 199                 if (head == *ring->tail)
 200                         break;
 201                 cqe = &ring->cqes[head & cq_ring_mask];
 202                 if (cqe->res != BS) {
 203                         printf("io: unexpected ret=%d\n", cqe->res);
 204                         return -1;
 205                 }
 206                 if (cqe->flags & IOCQE_FLAG_CACHEHIT)
 207                         s->cachehit++;
 208                 else
 209                         s->cachemiss++;
 210                 reaped++;
 211                 head++;
 212         } while (1);
 213
 214         s->inflight -= reaped;
 215         *ring->head = head;
 216         barrier();
 217         return reaped;
 218 }
 219
 220 static void *submitter_fn(void *data)
 221 {
 222         struct submitter *s = data;
 223         int ret, prepped;
 224
 225         printf("submitter=%d\n", gettid());
 226
 227         srand48_r(pthread_self(), &s->rand);
 228
 229         prepped = 0;
 230         do {
 231                 int to_wait, to_submit, this_reap, to_prep;
 232
 233                 if (!prepped && s->inflight < DEPTH) {
 234                         to_prep = min(DEPTH - s->inflight, BATCH_SUBMIT);
 235                         prepped = prep_more_ios(s, to_prep);
 236                 }
 237                 s->inflight += prepped;
 238 submit_more:
 239                 to_submit = prepped;
 240 submit:
 241                 if (s->inflight + BATCH_SUBMIT < DEPTH)
 242                         to_wait = 0;
 243                 else
 244                         to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
 245
 246                 ret = io_uring_enter(s, to_submit, to_wait,
 247                                         IORING_ENTER_GETEVENTS);
 248                 s->calls++;
 249
 250                 this_reap = reap_events(s);
 251                 if (this_reap == -1)
 252                         break;
 253                 s->reaps += this_reap;
 254
 255                 if (ret >= 0) {
 256                         if (!ret) {
 257                                 to_submit = 0;
 258                                 if (s->inflight)
 259                                         goto submit;
 260                                 continue;
 261                         } else if (ret < to_submit) {
 262                                 int diff = to_submit - ret;
 263
 264                                 s->done += ret;
 265                                 prepped -= diff;
 266                                 goto submit_more;
 267                         }
 268                         s->done += ret;
 269                         prepped = 0;
 270                         continue;
 271                 } else if (ret < 0) {
 272                         if (errno == EAGAIN) {
 273                                 if (s->finish)
 274                                         break;
 275                                 if (this_reap)
 276                                         goto submit;
 277                                 to_submit = 0;
 278                                 goto submit;
 279                         }
 280                         printf("io_submit: %s\n", strerror(errno));
 281                         break;
 282                 }
 283         } while (!s->finish);
 284
 285         finish = 1;
 286         return NULL;
 287 }
 288
 289 static void sig_int(int sig)
 290 {
 291         printf("Exiting on signal %d\n", sig);
 292         submitters[0].finish = 1;
 293         finish = 1;
 294 }
 295
 296 static void arm_sig_int(void)
 297 {
 298         struct sigaction act;
 299
 300         memset(&act, 0, sizeof(act));
 301         act.sa_handler = sig_int;
 302         act.sa_flags = SA_RESTART;
 303         sigaction(SIGINT, &act, NULL);
 304 }
 305
 306 static int setup_ring(struct submitter *s)
 307 {
 308         struct io_sq_ring *sring = &s->sq_ring;
 309         struct io_cq_ring *cring = &s->cq_ring;
 310         struct io_uring_params p;
 311         void *ptr;
 312         int fd;
 313
 314         memset(&p, 0, sizeof(p));
 315
 316         if (polled)
 317                 p.flags |= IORING_SETUP_IOPOLL;
 318         if (buffered)
 319                 p.flags |= IORING_SETUP_SQWQ;
 320         else if (sq_thread) {
 321                 p.flags |= IORING_SETUP_SQTHREAD;
 322                 p.sq_thread_cpu = sq_thread_cpu;
 323         }
 324
 325         if (fixedbufs)
 326                 fd = io_uring_setup(DEPTH, s->iovecs, DEPTH, &p);
 327         else
 328                 fd = io_uring_setup(DEPTH, NULL, 0, &p);
 329         if (fd < 0) {
 330                 perror("io_uring_setup");
 331                 return 1;
 332         }
 333
 334         s->ring_fd = fd;
 335         ptr = mmap(0, p.sq_off.array + p.sq_entries * sizeof(__u32),
 336                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 337                         IORING_OFF_SQ_RING);
 338         printf("sq_ring ptr = 0x%p\n", ptr);
 339         sring->head = ptr + p.sq_off.head;
 340         sring->tail = ptr + p.sq_off.tail;
 341         sring->ring_mask = ptr + p.sq_off.ring_mask;
 342         sring->ring_entries = ptr + p.sq_off.ring_entries;
 343         sring->array = ptr + p.sq_off.array;
 344         sq_ring_mask = *sring->ring_mask;
 345
 346         s->sqes = mmap(0, p.sq_entries * sizeof(struct io_uring_sqe),
 347                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 348                         IORING_OFF_SQES);
 349         printf("sqes ptr    = 0x%p\n", s->sqes);
 350
 351         ptr = mmap(0, p.cq_off.cqes + p.cq_entries * sizeof(struct io_uring_cqe),
 352                         PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
 353                         IORING_OFF_CQ_RING);
 354         printf("cq_ring ptr = 0x%p\n", ptr);
 355         cring->head = ptr + p.cq_off.head;
 356         cring->tail = ptr + p.cq_off.tail;
 357         cring->ring_mask = ptr + p.cq_off.ring_mask;
 358         cring->ring_entries = ptr + p.cq_off.ring_entries;
 359         cring->cqes = ptr + p.cq_off.cqes;
 360         cq_ring_mask = *cring->ring_mask;
 361         return 0;
 362 }
 363
 364 int main(int argc, char *argv[])
 365 {
 366         struct submitter *s = &submitters[0];
 367         unsigned long done, calls, reap, cache_hit, cache_miss;
 368         int err, i, flags, fd;
 369         struct rlimit rlim;
 370         void *ret;
 371
 372         if (argc < 2) {
 373                 printf("%s: filename\n", argv[0]);
 374                 return 1;
 375         }
 376
 377         flags = O_RDONLY;
 378         if (!buffered)
 379                 flags |= O_DIRECT;
 380
 381         i = 1;
 382         while (i < argc) {
 383                 struct file *f = &s->files[s->nr_files];
 384
 385                 fd = open(argv[i], flags);
 386                 if (fd < 0) {
 387                         perror("open");
 388                         return 1;
 389                 }
 390                 f->fd = fd;
 391                 if (get_file_size(f)) {
 392                         printf("failed getting size of device/file\n");
 393                         return 1;
 394                 }
 395                 if (f->max_blocks <= 1) {
 396                         printf("Zero file/device size?\n");
 397                         return 1;
 398                 }
 399                 f->max_blocks--;
 400
 401                 printf("Added file %s\n", argv[i]);
 402                 s->nr_files++;
 403                 i++;
 404         }
 405
 406         rlim.rlim_cur = RLIM_INFINITY;
 407         rlim.rlim_max = RLIM_INFINITY;
 408         if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
 409                 perror("setrlimit");
 410                 return 1;
 411         }
 412
 413         arm_sig_int();
 414
 415         for (i = 0; i < DEPTH; i++) {
 416                 void *buf;
 417
 418                 if (posix_memalign(&buf, BS, BS)) {
 419                         printf("failed alloc\n");
 420                         return 1;
 421                 }
 422                 s->iovecs[i].iov_base = buf;
 423                 s->iovecs[i].iov_len = BS;
 424         }
 425
 426         err = setup_ring(s);
 427         if (err) {
 428                 printf("ring setup failed: %s, %d\n", strerror(errno), err);
 429                 return 1;
 430         }
 431         printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
 432         printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
 433
 434         pthread_create(&s->thread, NULL, submitter_fn, s);
 435
 436         cache_hit = cache_miss = reap = calls = done = 0;
 437         do {
 438                 unsigned long this_done = 0;
 439                 unsigned long this_reap = 0;
 440                 unsigned long this_call = 0;
 441                 unsigned long this_cache_hit = 0;
 442                 unsigned long this_cache_miss = 0;
 443                 unsigned long rpc = 0, ipc = 0;
 444                 double hit = 0.0;
 445
 446                 sleep(1);
 447                 this_done += s->done;
 448                 this_call += s->calls;
 449                 this_reap += s->reaps;
 450                 this_cache_hit += s->cachehit;
 451                 this_cache_miss += s->cachemiss;
 452                 if (this_cache_hit && this_cache_miss) {
 453                         unsigned long hits, total;
 454
 455                         hits = this_cache_hit - cache_hit;
 456                         total = hits + this_cache_miss - cache_miss;
 457                         hit = (double) hits / (double) total;
 458                         hit *= 100.0;
 459                 }
 460                 if (this_call - calls) {
 461                         rpc = (this_done - done) / (this_call - calls);
 462                         ipc = (this_reap - reap) / (this_call - calls);
 463                 }
 464                 printf("IOPS=%lu, IOS/call=%lu/%lu, inflight=%u (head=%u tail=%u), Cachehit=%0.2f%%\n",
 465                                 this_done - done, rpc, ipc, s->inflight,
 466                                 *s->cq_ring.head, *s->cq_ring.tail, hit);
 467                 done = this_done;
 468                 calls = this_call;
 469                 reap = this_reap;
 470                 cache_hit = s->cachehit;
 471                 cache_miss = s->cachemiss;
 472         } while (!finish);
 473
 474         pthread_join(s->thread, &ret);
 475         close(s->ring_fd);
 476         return 0;
 477 }