swh:1:snp:c3bf2749e3476071fa748f67b0ffa2fdc5fe49d9
Tip revision: 7e57714cd0ad2d5bb90e50b5096a0e671dec1ef3 authored by Linus Torvalds on 27 February 2022, 22:36:33 UTC
Linux 5.17-rc6
Linux 5.17-rc6
Tip revision: 7e57714
io_uring-bench.c
// SPDX-License-Identifier: GPL-2.0
/*
* Simple benchmark program that uses the various features of io_uring
* to provide fast random access to a device/file. It has various
* options that are control how we use io_uring, see the OPTIONS section
* below. This uses the raw io_uring interface.
*
* Copyright (C) 2018-2019 Jens Axboe
*/
#include <stdio.h>
#include <errno.h>
#include <assert.h>
#include <stdlib.h>
#include <stddef.h>
#include <signal.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <sys/resource.h>
#include <sys/mman.h>
#include <sys/uio.h>
#include <linux/fs.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include <sched.h>
#include "liburing.h"
#include "barrier.h"
#define min(a, b) ((a < b) ? (a) : (b))
struct io_sq_ring {
unsigned *head;
unsigned *tail;
unsigned *ring_mask;
unsigned *ring_entries;
unsigned *flags;
unsigned *array;
};
struct io_cq_ring {
unsigned *head;
unsigned *tail;
unsigned *ring_mask;
unsigned *ring_entries;
struct io_uring_cqe *cqes;
};
#define DEPTH 128
#define BATCH_SUBMIT 32
#define BATCH_COMPLETE 32
#define BS 4096
#define MAX_FDS 16
static unsigned sq_ring_mask, cq_ring_mask;
struct file {
unsigned long max_blocks;
unsigned pending_ios;
int real_fd;
int fixed_fd;
};
struct submitter {
pthread_t thread;
int ring_fd;
struct drand48_data rand;
struct io_sq_ring sq_ring;
struct io_uring_sqe *sqes;
struct iovec iovecs[DEPTH];
struct io_cq_ring cq_ring;
int inflight;
unsigned long reaps;
unsigned long done;
unsigned long calls;
volatile int finish;
__s32 *fds;
struct file files[MAX_FDS];
unsigned nr_files;
unsigned cur_file;
};
static struct submitter submitters[1];
static volatile int finish;
/*
* OPTIONS: Set these to test the various features of io_uring.
*/
static int polled = 1; /* use IO polling */
static int fixedbufs = 1; /* use fixed user buffers */
static int register_files = 1; /* use fixed files */
static int buffered = 0; /* use buffered IO, not O_DIRECT */
static int sq_thread_poll = 0; /* use kernel submission/poller thread */
static int sq_thread_cpu = -1; /* pin above thread to this CPU */
static int do_nop = 0; /* no-op SQ ring commands */
static int io_uring_register_buffers(struct submitter *s)
{
if (do_nop)
return 0;
return io_uring_register(s->ring_fd, IORING_REGISTER_BUFFERS, s->iovecs,
DEPTH);
}
static int io_uring_register_files(struct submitter *s)
{
unsigned i;
if (do_nop)
return 0;
s->fds = calloc(s->nr_files, sizeof(__s32));
for (i = 0; i < s->nr_files; i++) {
s->fds[i] = s->files[i].real_fd;
s->files[i].fixed_fd = i;
}
return io_uring_register(s->ring_fd, IORING_REGISTER_FILES, s->fds,
s->nr_files);
}
static int lk_gettid(void)
{
return syscall(__NR_gettid);
}
static unsigned file_depth(struct submitter *s)
{
return (DEPTH + s->nr_files - 1) / s->nr_files;
}
static void init_io(struct submitter *s, unsigned index)
{
struct io_uring_sqe *sqe = &s->sqes[index];
unsigned long offset;
struct file *f;
long r;
if (do_nop) {
sqe->opcode = IORING_OP_NOP;
return;
}
if (s->nr_files == 1) {
f = &s->files[0];
} else {
f = &s->files[s->cur_file];
if (f->pending_ios >= file_depth(s)) {
s->cur_file++;
if (s->cur_file == s->nr_files)
s->cur_file = 0;
f = &s->files[s->cur_file];
}
}
f->pending_ios++;
lrand48_r(&s->rand, &r);
offset = (r % (f->max_blocks - 1)) * BS;
if (register_files) {
sqe->flags = IOSQE_FIXED_FILE;
sqe->fd = f->fixed_fd;
} else {
sqe->flags = 0;
sqe->fd = f->real_fd;
}
if (fixedbufs) {
sqe->opcode = IORING_OP_READ_FIXED;
sqe->addr = (unsigned long) s->iovecs[index].iov_base;
sqe->len = BS;
sqe->buf_index = index;
} else {
sqe->opcode = IORING_OP_READV;
sqe->addr = (unsigned long) &s->iovecs[index];
sqe->len = 1;
sqe->buf_index = 0;
}
sqe->ioprio = 0;
sqe->off = offset;
sqe->user_data = (unsigned long) f;
}
static int prep_more_ios(struct submitter *s, unsigned max_ios)
{
struct io_sq_ring *ring = &s->sq_ring;
unsigned index, tail, next_tail, prepped = 0;
next_tail = tail = *ring->tail;
do {
next_tail++;
read_barrier();
if (next_tail == *ring->head)
break;
index = tail & sq_ring_mask;
init_io(s, index);
ring->array[index] = index;
prepped++;
tail = next_tail;
} while (prepped < max_ios);
if (*ring->tail != tail) {
/* order tail store with writes to sqes above */
write_barrier();
*ring->tail = tail;
write_barrier();
}
return prepped;
}
static int get_file_size(struct file *f)
{
struct stat st;
if (fstat(f->real_fd, &st) < 0)
return -1;
if (S_ISBLK(st.st_mode)) {
unsigned long long bytes;
if (ioctl(f->real_fd, BLKGETSIZE64, &bytes) != 0)
return -1;
f->max_blocks = bytes / BS;
return 0;
} else if (S_ISREG(st.st_mode)) {
f->max_blocks = st.st_size / BS;
return 0;
}
return -1;
}
static int reap_events(struct submitter *s)
{
struct io_cq_ring *ring = &s->cq_ring;
struct io_uring_cqe *cqe;
unsigned head, reaped = 0;
head = *ring->head;
do {
struct file *f;
read_barrier();
if (head == *ring->tail)
break;
cqe = &ring->cqes[head & cq_ring_mask];
if (!do_nop) {
f = (struct file *) (uintptr_t) cqe->user_data;
f->pending_ios--;
if (cqe->res != BS) {
printf("io: unexpected ret=%d\n", cqe->res);
if (polled && cqe->res == -EOPNOTSUPP)
printf("Your filesystem doesn't support poll\n");
return -1;
}
}
reaped++;
head++;
} while (1);
s->inflight -= reaped;
*ring->head = head;
write_barrier();
return reaped;
}
static void *submitter_fn(void *data)
{
struct submitter *s = data;
struct io_sq_ring *ring = &s->sq_ring;
int ret, prepped;
printf("submitter=%d\n", lk_gettid());
srand48_r(pthread_self(), &s->rand);
prepped = 0;
do {
int to_wait, to_submit, this_reap, to_prep;
if (!prepped && s->inflight < DEPTH) {
to_prep = min(DEPTH - s->inflight, BATCH_SUBMIT);
prepped = prep_more_ios(s, to_prep);
}
s->inflight += prepped;
submit_more:
to_submit = prepped;
submit:
if (to_submit && (s->inflight + to_submit <= DEPTH))
to_wait = 0;
else
to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
/*
* Only need to call io_uring_enter if we're not using SQ thread
* poll, or if IORING_SQ_NEED_WAKEUP is set.
*/
if (!sq_thread_poll || (*ring->flags & IORING_SQ_NEED_WAKEUP)) {
unsigned flags = 0;
if (to_wait)
flags = IORING_ENTER_GETEVENTS;
if ((*ring->flags & IORING_SQ_NEED_WAKEUP))
flags |= IORING_ENTER_SQ_WAKEUP;
ret = io_uring_enter(s->ring_fd, to_submit, to_wait,
flags, NULL);
s->calls++;
}
/*
* For non SQ thread poll, we already got the events we needed
* through the io_uring_enter() above. For SQ thread poll, we
* need to loop here until we find enough events.
*/
this_reap = 0;
do {
int r;
r = reap_events(s);
if (r == -1) {
s->finish = 1;
break;
} else if (r > 0)
this_reap += r;
} while (sq_thread_poll && this_reap < to_wait);
s->reaps += this_reap;
if (ret >= 0) {
if (!ret) {
to_submit = 0;
if (s->inflight)
goto submit;
continue;
} else if (ret < to_submit) {
int diff = to_submit - ret;
s->done += ret;
prepped -= diff;
goto submit_more;
}
s->done += ret;
prepped = 0;
continue;
} else if (ret < 0) {
if (errno == EAGAIN) {
if (s->finish)
break;
if (this_reap)
goto submit;
to_submit = 0;
goto submit;
}
printf("io_submit: %s\n", strerror(errno));
break;
}
} while (!s->finish);
finish = 1;
return NULL;
}
static void sig_int(int sig)
{
printf("Exiting on signal %d\n", sig);
submitters[0].finish = 1;
finish = 1;
}
static void arm_sig_int(void)
{
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = sig_int;
act.sa_flags = SA_RESTART;
sigaction(SIGINT, &act, NULL);
}
static int setup_ring(struct submitter *s)
{
struct io_sq_ring *sring = &s->sq_ring;
struct io_cq_ring *cring = &s->cq_ring;
struct io_uring_params p;
int ret, fd;
void *ptr;
memset(&p, 0, sizeof(p));
if (polled && !do_nop)
p.flags |= IORING_SETUP_IOPOLL;
if (sq_thread_poll) {
p.flags |= IORING_SETUP_SQPOLL;
if (sq_thread_cpu != -1) {
p.flags |= IORING_SETUP_SQ_AFF;
p.sq_thread_cpu = sq_thread_cpu;
}
}
fd = io_uring_setup(DEPTH, &p);
if (fd < 0) {
perror("io_uring_setup");
return 1;
}
s->ring_fd = fd;
if (fixedbufs) {
ret = io_uring_register_buffers(s);
if (ret < 0) {
perror("io_uring_register_buffers");
return 1;
}
}
if (register_files) {
ret = io_uring_register_files(s);
if (ret < 0) {
perror("io_uring_register_files");
return 1;
}
}
ptr = mmap(0, p.sq_off.array + p.sq_entries * sizeof(__u32),
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
IORING_OFF_SQ_RING);
printf("sq_ring ptr = 0x%p\n", ptr);
sring->head = ptr + p.sq_off.head;
sring->tail = ptr + p.sq_off.tail;
sring->ring_mask = ptr + p.sq_off.ring_mask;
sring->ring_entries = ptr + p.sq_off.ring_entries;
sring->flags = ptr + p.sq_off.flags;
sring->array = ptr + p.sq_off.array;
sq_ring_mask = *sring->ring_mask;
s->sqes = mmap(0, p.sq_entries * sizeof(struct io_uring_sqe),
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
IORING_OFF_SQES);
printf("sqes ptr = 0x%p\n", s->sqes);
ptr = mmap(0, p.cq_off.cqes + p.cq_entries * sizeof(struct io_uring_cqe),
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
IORING_OFF_CQ_RING);
printf("cq_ring ptr = 0x%p\n", ptr);
cring->head = ptr + p.cq_off.head;
cring->tail = ptr + p.cq_off.tail;
cring->ring_mask = ptr + p.cq_off.ring_mask;
cring->ring_entries = ptr + p.cq_off.ring_entries;
cring->cqes = ptr + p.cq_off.cqes;
cq_ring_mask = *cring->ring_mask;
return 0;
}
static void file_depths(char *buf)
{
struct submitter *s = &submitters[0];
unsigned i;
char *p;
buf[0] = '\0';
p = buf;
for (i = 0; i < s->nr_files; i++) {
struct file *f = &s->files[i];
if (i + 1 == s->nr_files)
p += sprintf(p, "%d", f->pending_ios);
else
p += sprintf(p, "%d, ", f->pending_ios);
}
}
int main(int argc, char *argv[])
{
struct submitter *s = &submitters[0];
unsigned long done, calls, reap;
int err, i, flags, fd;
char *fdepths;
void *ret;
if (!do_nop && argc < 2) {
printf("%s: filename\n", argv[0]);
return 1;
}
flags = O_RDONLY | O_NOATIME;
if (!buffered)
flags |= O_DIRECT;
i = 1;
while (!do_nop && i < argc) {
struct file *f;
if (s->nr_files == MAX_FDS) {
printf("Max number of files (%d) reached\n", MAX_FDS);
break;
}
fd = open(argv[i], flags);
if (fd < 0) {
perror("open");
return 1;
}
f = &s->files[s->nr_files];
f->real_fd = fd;
if (get_file_size(f)) {
printf("failed getting size of device/file\n");
return 1;
}
if (f->max_blocks <= 1) {
printf("Zero file/device size?\n");
return 1;
}
f->max_blocks--;
printf("Added file %s\n", argv[i]);
s->nr_files++;
i++;
}
if (fixedbufs) {
struct rlimit rlim;
rlim.rlim_cur = RLIM_INFINITY;
rlim.rlim_max = RLIM_INFINITY;
if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
perror("setrlimit");
return 1;
}
}
arm_sig_int();
for (i = 0; i < DEPTH; i++) {
void *buf;
if (posix_memalign(&buf, BS, BS)) {
printf("failed alloc\n");
return 1;
}
s->iovecs[i].iov_base = buf;
s->iovecs[i].iov_len = BS;
}
err = setup_ring(s);
if (err) {
printf("ring setup failed: %s, %d\n", strerror(errno), err);
return 1;
}
printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
pthread_create(&s->thread, NULL, submitter_fn, s);
fdepths = malloc(8 * s->nr_files);
reap = calls = done = 0;
do {
unsigned long this_done = 0;
unsigned long this_reap = 0;
unsigned long this_call = 0;
unsigned long rpc = 0, ipc = 0;
sleep(1);
this_done += s->done;
this_call += s->calls;
this_reap += s->reaps;
if (this_call - calls) {
rpc = (this_done - done) / (this_call - calls);
ipc = (this_reap - reap) / (this_call - calls);
} else
rpc = ipc = -1;
file_depths(fdepths);
printf("IOPS=%lu, IOS/call=%ld/%ld, inflight=%u (%s)\n",
this_done - done, rpc, ipc, s->inflight,
fdepths);
done = this_done;
calls = this_call;
reap = this_reap;
} while (!finish);
pthread_join(s->thread, &ret);
close(s->ring_fd);
free(fdepths);
return 0;
}