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authorJens Axboe <axboe@kernel.dk>2019-03-06 09:03:50 -0700
committerJens Axboe <axboe@kernel.dk>2019-03-06 13:00:16 -0700
commit21b4aa5d20fd07207e73270cadffed5c63fb4343 (patch)
treef9efcd15b170905dd1d9a4f1801b26b0ec90c34e /tools
parentio_uring: allow workqueue item to handle multiple buffered requests (diff)
downloadlinux-dev-21b4aa5d20fd07207e73270cadffed5c63fb4343.tar.xz
linux-dev-21b4aa5d20fd07207e73270cadffed5c63fb4343.zip
io_uring: add a few test tools
This adds two test programs in tools/io_uring/ that demonstrate both the raw io_uring API (and all features) through a small benchmark app, io_uring-bench, and the liburing exposed API in a simplified cp(1) implementation through io_uring-cp. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'tools')
-rw-r--r--tools/io_uring/Makefile18
-rw-r--r--tools/io_uring/README29
-rw-r--r--tools/io_uring/barrier.h16
-rw-r--r--tools/io_uring/io_uring-bench.c616
-rw-r--r--tools/io_uring/io_uring-cp.c251
-rw-r--r--tools/io_uring/liburing.h143
-rw-r--r--tools/io_uring/queue.c164
-rw-r--r--tools/io_uring/setup.c103
-rw-r--r--tools/io_uring/syscall.c40
9 files changed, 1380 insertions, 0 deletions
diff --git a/tools/io_uring/Makefile b/tools/io_uring/Makefile
new file mode 100644
index 000000000000..f79522fc37b5
--- /dev/null
+++ b/tools/io_uring/Makefile
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for io_uring test tools
+CFLAGS += -Wall -Wextra -g -D_GNU_SOURCE
+LDLIBS += -lpthread
+
+all: io_uring-cp io_uring-bench
+%: %.c
+ $(CC) $(CFLAGS) -o $@ $^
+
+io_uring-bench: syscall.o io_uring-bench.o
+ $(CC) $(CFLAGS) $(LDLIBS) -o $@ $^
+
+io_uring-cp: setup.o syscall.o queue.o
+
+clean:
+ $(RM) io_uring-cp io_uring-bench *.o
+
+.PHONY: all clean
diff --git a/tools/io_uring/README b/tools/io_uring/README
new file mode 100644
index 000000000000..67fd70115cff
--- /dev/null
+++ b/tools/io_uring/README
@@ -0,0 +1,29 @@
+This directory includes a few programs that demonstrate how to use io_uring
+in an application. The examples are:
+
+io_uring-cp
+ A very basic io_uring implementation of cp(1). It takes two
+ arguments, copies the first argument to the second. This example
+ is part of liburing, and hence uses the simplified liburing API
+ for setting up an io_uring instance, submitting IO, completing IO,
+ etc. The support functions in queue.c and setup.c are straight
+ out of liburing.
+
+io_uring-bench
+ Benchmark program that does random reads on a number of files. This
+ app demonstrates the various features of io_uring, like fixed files,
+ fixed buffers, and polled IO. There are options in the program to
+ control which features to use. Arguments is the file (or files) that
+ io_uring-bench should operate on. This uses the raw io_uring
+ interface.
+
+liburing can be cloned with git here:
+
+ git://git.kernel.dk/liburing
+
+and contains a number of unit tests as well for testing io_uring. It also
+comes with man pages for the three system calls.
+
+Fio includes an io_uring engine, you can clone fio here:
+
+ git://git.kernel.dk/fio
diff --git a/tools/io_uring/barrier.h b/tools/io_uring/barrier.h
new file mode 100644
index 000000000000..ef00f6722ba9
--- /dev/null
+++ b/tools/io_uring/barrier.h
@@ -0,0 +1,16 @@
+#ifndef LIBURING_BARRIER_H
+#define LIBURING_BARRIER_H
+
+#if defined(__x86_64) || defined(__i386__)
+#define read_barrier() __asm__ __volatile__("":::"memory")
+#define write_barrier() __asm__ __volatile__("":::"memory")
+#else
+/*
+ * Add arch appropriate definitions. Be safe and use full barriers for
+ * archs we don't have support for.
+ */
+#define read_barrier() __sync_synchronize()
+#define write_barrier() __sync_synchronize()
+#endif
+
+#endif
diff --git a/tools/io_uring/io_uring-bench.c b/tools/io_uring/io_uring-bench.c
new file mode 100644
index 000000000000..512306a37531
--- /dev/null
+++ b/tools/io_uring/io_uring-bench.c
@@ -0,0 +1,616 @@
+// 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"
+
+#ifndef IOCQE_FLAG_CACHEHIT
+#define IOCQE_FLAG_CACHEHIT (1U << 0)
+#endif
+
+#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;
+ unsigned long cachehit, cachemiss;
+ 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 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;
+ }
+ }
+ if (cqe->flags & IOCQE_FLAG_CACHEHIT)
+ s->cachehit++;
+ else
+ s->cachemiss++;
+ 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", 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, cache_hit, cache_miss;
+ 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);
+ cache_hit = cache_miss = reap = calls = done = 0;
+ do {
+ unsigned long this_done = 0;
+ unsigned long this_reap = 0;
+ unsigned long this_call = 0;
+ unsigned long this_cache_hit = 0;
+ unsigned long this_cache_miss = 0;
+ unsigned long rpc = 0, ipc = 0;
+ double hit = 0.0;
+
+ sleep(1);
+ this_done += s->done;
+ this_call += s->calls;
+ this_reap += s->reaps;
+ this_cache_hit += s->cachehit;
+ this_cache_miss += s->cachemiss;
+ if (this_cache_hit && this_cache_miss) {
+ unsigned long hits, total;
+
+ hits = this_cache_hit - cache_hit;
+ total = hits + this_cache_miss - cache_miss;
+ hit = (double) hits / (double) total;
+ hit *= 100.0;
+ }
+ 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), Cachehit=%0.2f%%\n",
+ this_done - done, rpc, ipc, s->inflight,
+ fdepths, hit);
+ done = this_done;
+ calls = this_call;
+ reap = this_reap;
+ cache_hit = s->cachehit;
+ cache_miss = s->cachemiss;
+ } while (!finish);
+
+ pthread_join(s->thread, &ret);
+ close(s->ring_fd);
+ free(fdepths);
+ return 0;
+}
diff --git a/tools/io_uring/io_uring-cp.c b/tools/io_uring/io_uring-cp.c
new file mode 100644
index 000000000000..633f65bb43a7
--- /dev/null
+++ b/tools/io_uring/io_uring-cp.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple test program that demonstrates a file copy through io_uring. This
+ * uses the API exposed by liburing.
+ *
+ * Copyright (C) 2018-2019 Jens Axboe
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+
+#include "liburing.h"
+
+#define QD 64
+#define BS (32*1024)
+
+static int infd, outfd;
+
+struct io_data {
+ int read;
+ off_t first_offset, offset;
+ size_t first_len;
+ struct iovec iov;
+};
+
+static int setup_context(unsigned entries, struct io_uring *ring)
+{
+ int ret;
+
+ ret = io_uring_queue_init(entries, ring, 0);
+ if (ret < 0) {
+ fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+ return -1;
+ }
+
+ return 0;
+}
+
+static int get_file_size(int fd, off_t *size)
+{
+ struct stat st;
+
+ if (fstat(fd, &st) < 0)
+ return -1;
+ if (S_ISREG(st.st_mode)) {
+ *size = st.st_size;
+ return 0;
+ } else if (S_ISBLK(st.st_mode)) {
+ unsigned long long bytes;
+
+ if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
+ return -1;
+
+ *size = bytes;
+ return 0;
+ }
+
+ return -1;
+}
+
+static void queue_prepped(struct io_uring *ring, struct io_data *data)
+{
+ struct io_uring_sqe *sqe;
+
+ sqe = io_uring_get_sqe(ring);
+ assert(sqe);
+
+ if (data->read)
+ io_uring_prep_readv(sqe, infd, &data->iov, 1, data->offset);
+ else
+ io_uring_prep_writev(sqe, outfd, &data->iov, 1, data->offset);
+
+ io_uring_sqe_set_data(sqe, data);
+}
+
+static int queue_read(struct io_uring *ring, off_t size, off_t offset)
+{
+ struct io_uring_sqe *sqe;
+ struct io_data *data;
+
+ sqe = io_uring_get_sqe(ring);
+ if (!sqe)
+ return 1;
+
+ data = malloc(size + sizeof(*data));
+ data->read = 1;
+ data->offset = data->first_offset = offset;
+
+ data->iov.iov_base = data + 1;
+ data->iov.iov_len = size;
+ data->first_len = size;
+
+ io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
+ io_uring_sqe_set_data(sqe, data);
+ return 0;
+}
+
+static void queue_write(struct io_uring *ring, struct io_data *data)
+{
+ data->read = 0;
+ data->offset = data->first_offset;
+
+ data->iov.iov_base = data + 1;
+ data->iov.iov_len = data->first_len;
+
+ queue_prepped(ring, data);
+ io_uring_submit(ring);
+}
+
+static int copy_file(struct io_uring *ring, off_t insize)
+{
+ unsigned long reads, writes;
+ struct io_uring_cqe *cqe;
+ off_t write_left, offset;
+ int ret;
+
+ write_left = insize;
+ writes = reads = offset = 0;
+
+ while (insize || write_left) {
+ unsigned long had_reads;
+ int got_comp;
+
+ /*
+ * Queue up as many reads as we can
+ */
+ had_reads = reads;
+ while (insize) {
+ off_t this_size = insize;
+
+ if (reads + writes >= QD)
+ break;
+ if (this_size > BS)
+ this_size = BS;
+ else if (!this_size)
+ break;
+
+ if (queue_read(ring, this_size, offset))
+ break;
+
+ insize -= this_size;
+ offset += this_size;
+ reads++;
+ }
+
+ if (had_reads != reads) {
+ ret = io_uring_submit(ring);
+ if (ret < 0) {
+ fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));
+ break;
+ }
+ }
+
+ /*
+ * Queue is full at this point. Find at least one completion.
+ */
+ got_comp = 0;
+ while (write_left) {
+ struct io_data *data;
+
+ if (!got_comp) {
+ ret = io_uring_wait_completion(ring, &cqe);
+ got_comp = 1;
+ } else
+ ret = io_uring_get_completion(ring, &cqe);
+ if (ret < 0) {
+ fprintf(stderr, "io_uring_get_completion: %s\n",
+ strerror(-ret));
+ return 1;
+ }
+ if (!cqe)
+ break;
+
+ data = (struct io_data *) (uintptr_t) cqe->user_data;
+ if (cqe->res < 0) {
+ if (cqe->res == -EAGAIN) {
+ queue_prepped(ring, data);
+ continue;
+ }
+ fprintf(stderr, "cqe failed: %s\n",
+ strerror(-cqe->res));
+ return 1;
+ } else if ((size_t) cqe->res != data->iov.iov_len) {
+ /* Short read/write, adjust and requeue */
+ data->iov.iov_base += cqe->res;
+ data->iov.iov_len -= cqe->res;
+ data->offset += cqe->res;
+ queue_prepped(ring, data);
+ continue;
+ }
+
+ /*
+ * All done. if write, nothing else to do. if read,
+ * queue up corresponding write.
+ */
+ if (data->read) {
+ queue_write(ring, data);
+ write_left -= data->first_len;
+ reads--;
+ writes++;
+ } else {
+ free(data);
+ writes--;
+ }
+ }
+ }
+
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ struct io_uring ring;
+ off_t insize;
+ int ret;
+
+ if (argc < 3) {
+ printf("%s: infile outfile\n", argv[0]);
+ return 1;
+ }
+
+ infd = open(argv[1], O_RDONLY);
+ if (infd < 0) {
+ perror("open infile");
+ return 1;
+ }
+ outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
+ if (outfd < 0) {
+ perror("open outfile");
+ return 1;
+ }
+
+ if (setup_context(QD, &ring))
+ return 1;
+ if (get_file_size(infd, &insize))
+ return 1;
+
+ ret = copy_file(&ring, insize);
+
+ close(infd);
+ close(outfd);
+ io_uring_queue_exit(&ring);
+ return ret;
+}
diff --git a/tools/io_uring/liburing.h b/tools/io_uring/liburing.h
new file mode 100644
index 000000000000..cab0f50257ba
--- /dev/null
+++ b/tools/io_uring/liburing.h
@@ -0,0 +1,143 @@
+#ifndef LIB_URING_H
+#define LIB_URING_H
+
+#include <sys/uio.h>
+#include <signal.h>
+#include <string.h>
+#include "../../include/uapi/linux/io_uring.h"
+
+/*
+ * Library interface to io_uring
+ */
+struct io_uring_sq {
+ unsigned *khead;
+ unsigned *ktail;
+ unsigned *kring_mask;
+ unsigned *kring_entries;
+ unsigned *kflags;
+ unsigned *kdropped;
+ unsigned *array;
+ struct io_uring_sqe *sqes;
+
+ unsigned sqe_head;
+ unsigned sqe_tail;
+
+ size_t ring_sz;
+};
+
+struct io_uring_cq {
+ unsigned *khead;
+ unsigned *ktail;
+ unsigned *kring_mask;
+ unsigned *kring_entries;
+ unsigned *koverflow;
+ struct io_uring_cqe *cqes;
+
+ size_t ring_sz;
+};
+
+struct io_uring {
+ struct io_uring_sq sq;
+ struct io_uring_cq cq;
+ int ring_fd;
+};
+
+/*
+ * System calls
+ */
+extern int io_uring_setup(unsigned entries, struct io_uring_params *p);
+extern int io_uring_enter(unsigned fd, unsigned to_submit,
+ unsigned min_complete, unsigned flags, sigset_t *sig);
+extern int io_uring_register(int fd, unsigned int opcode, void *arg,
+ unsigned int nr_args);
+
+/*
+ * Library interface
+ */
+extern int io_uring_queue_init(unsigned entries, struct io_uring *ring,
+ unsigned flags);
+extern int io_uring_queue_mmap(int fd, struct io_uring_params *p,
+ struct io_uring *ring);
+extern void io_uring_queue_exit(struct io_uring *ring);
+extern int io_uring_get_completion(struct io_uring *ring,
+ struct io_uring_cqe **cqe_ptr);
+extern int io_uring_wait_completion(struct io_uring *ring,
+ struct io_uring_cqe **cqe_ptr);
+extern int io_uring_submit(struct io_uring *ring);
+extern struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring);
+
+/*
+ * Command prep helpers
+ */
+static inline void io_uring_sqe_set_data(struct io_uring_sqe *sqe, void *data)
+{
+ sqe->user_data = (unsigned long) data;
+}
+
+static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
+ void *addr, unsigned len, off_t offset)
+{
+ memset(sqe, 0, sizeof(*sqe));
+ sqe->opcode = op;
+ sqe->fd = fd;
+ sqe->off = offset;
+ sqe->addr = (unsigned long) addr;
+ sqe->len = len;
+}
+
+static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
+ struct iovec *iovecs, unsigned nr_vecs,
+ off_t offset)
+{
+ io_uring_prep_rw(IORING_OP_READV, sqe, fd, iovecs, nr_vecs, offset);
+}
+
+static inline void io_uring_prep_read_fixed(struct io_uring_sqe *sqe, int fd,
+ void *buf, unsigned nbytes,
+ off_t offset)
+{
+ io_uring_prep_rw(IORING_OP_READ_FIXED, sqe, fd, buf, nbytes, offset);
+}
+
+static inline void io_uring_prep_writev(struct io_uring_sqe *sqe, int fd,
+ struct iovec *iovecs, unsigned nr_vecs,
+ off_t offset)
+{
+ io_uring_prep_rw(IORING_OP_WRITEV, sqe, fd, iovecs, nr_vecs, offset);
+}
+
+static inline void io_uring_prep_write_fixed(struct io_uring_sqe *sqe, int fd,
+ void *buf, unsigned nbytes,
+ off_t offset)
+{
+ io_uring_prep_rw(IORING_OP_WRITE_FIXED, sqe, fd, buf, nbytes, offset);
+}
+
+static inline void io_uring_prep_poll_add(struct io_uring_sqe *sqe, int fd,
+ short poll_mask)
+{
+ memset(sqe, 0, sizeof(*sqe));
+ sqe->opcode = IORING_OP_POLL_ADD;
+ sqe->fd = fd;
+ sqe->poll_events = poll_mask;
+}
+
+static inline void io_uring_prep_poll_remove(struct io_uring_sqe *sqe,
+ void *user_data)
+{
+ memset(sqe, 0, sizeof(*sqe));
+ sqe->opcode = IORING_OP_POLL_REMOVE;
+ sqe->addr = (unsigned long) user_data;
+}
+
+static inline void io_uring_prep_fsync(struct io_uring_sqe *sqe, int fd,
+ int datasync)
+{
+ memset(sqe, 0, sizeof(*sqe));
+ sqe->opcode = IORING_OP_FSYNC;
+ sqe->fd = fd;
+ if (datasync)
+ sqe->fsync_flags = IORING_FSYNC_DATASYNC;
+}
+
+#endif
diff --git a/tools/io_uring/queue.c b/tools/io_uring/queue.c
new file mode 100644
index 000000000000..88505e873ad9
--- /dev/null
+++ b/tools/io_uring/queue.c
@@ -0,0 +1,164 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include "liburing.h"
+#include "barrier.h"
+
+static int __io_uring_get_completion(struct io_uring *ring,
+ struct io_uring_cqe **cqe_ptr, int wait)
+{
+ struct io_uring_cq *cq = &ring->cq;
+ const unsigned mask = *cq->kring_mask;
+ unsigned head;
+ int ret;
+
+ *cqe_ptr = NULL;
+ head = *cq->khead;
+ do {
+ /*
+ * It's necessary to use a read_barrier() before reading
+ * the CQ tail, since the kernel updates it locklessly. The
+ * kernel has the matching store barrier for the update. The
+ * kernel also ensures that previous stores to CQEs are ordered
+ * with the tail update.
+ */
+ read_barrier();
+ if (head != *cq->ktail) {
+ *cqe_ptr = &cq->cqes[head & mask];
+ break;
+ }
+ if (!wait)
+ break;
+ ret = io_uring_enter(ring->ring_fd, 0, 1,
+ IORING_ENTER_GETEVENTS, NULL);
+ if (ret < 0)
+ return -errno;
+ } while (1);
+
+ if (*cqe_ptr) {
+ *cq->khead = head + 1;
+ /*
+ * Ensure that the kernel sees our new head, the kernel has
+ * the matching read barrier.
+ */
+ write_barrier();
+ }
+
+ return 0;
+}
+
+/*
+ * Return an IO completion, if one is readily available
+ */
+int io_uring_get_completion(struct io_uring *ring,
+ struct io_uring_cqe **cqe_ptr)
+{
+ return __io_uring_get_completion(ring, cqe_ptr, 0);
+}
+
+/*
+ * Return an IO completion, waiting for it if necessary
+ */
+int io_uring_wait_completion(struct io_uring *ring,
+ struct io_uring_cqe **cqe_ptr)
+{
+ return __io_uring_get_completion(ring, cqe_ptr, 1);
+}
+
+/*
+ * Submit sqes acquired from io_uring_get_sqe() to the kernel.
+ *
+ * Returns number of sqes submitted
+ */
+int io_uring_submit(struct io_uring *ring)
+{
+ struct io_uring_sq *sq = &ring->sq;
+ const unsigned mask = *sq->kring_mask;
+ unsigned ktail, ktail_next, submitted;
+ int ret;
+
+ /*
+ * If we have pending IO in the kring, submit it first. We need a
+ * read barrier here to match the kernels store barrier when updating
+ * the SQ head.
+ */
+ read_barrier();
+ if (*sq->khead != *sq->ktail) {
+ submitted = *sq->kring_entries;
+ goto submit;
+ }
+
+ if (sq->sqe_head == sq->sqe_tail)
+ return 0;
+
+ /*
+ * Fill in sqes that we have queued up, adding them to the kernel ring
+ */
+ submitted = 0;
+ ktail = ktail_next = *sq->ktail;
+ while (sq->sqe_head < sq->sqe_tail) {
+ ktail_next++;
+ read_barrier();
+
+ sq->array[ktail & mask] = sq->sqe_head & mask;
+ ktail = ktail_next;
+
+ sq->sqe_head++;
+ submitted++;
+ }
+
+ if (!submitted)
+ return 0;
+
+ if (*sq->ktail != ktail) {
+ /*
+ * First write barrier ensures that the SQE stores are updated
+ * with the tail update. This is needed so that the kernel
+ * will never see a tail update without the preceeding sQE
+ * stores being done.
+ */
+ write_barrier();
+ *sq->ktail = ktail;
+ /*
+ * The kernel has the matching read barrier for reading the
+ * SQ tail.
+ */
+ write_barrier();
+ }
+
+submit:
+ ret = io_uring_enter(ring->ring_fd, submitted, 0,
+ IORING_ENTER_GETEVENTS, NULL);
+ if (ret < 0)
+ return -errno;
+
+ return 0;
+}
+
+/*
+ * Return an sqe to fill. Application must later call io_uring_submit()
+ * when it's ready to tell the kernel about it. The caller may call this
+ * function multiple times before calling io_uring_submit().
+ *
+ * Returns a vacant sqe, or NULL if we're full.
+ */
+struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring)
+{
+ struct io_uring_sq *sq = &ring->sq;
+ unsigned next = sq->sqe_tail + 1;
+ struct io_uring_sqe *sqe;
+
+ /*
+ * All sqes are used
+ */
+ if (next - sq->sqe_head > *sq->kring_entries)
+ return NULL;
+
+ sqe = &sq->sqes[sq->sqe_tail & *sq->kring_mask];
+ sq->sqe_tail = next;
+ return sqe;
+}
diff --git a/tools/io_uring/setup.c b/tools/io_uring/setup.c
new file mode 100644
index 000000000000..4da19a77132c
--- /dev/null
+++ b/tools/io_uring/setup.c
@@ -0,0 +1,103 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include "liburing.h"
+
+static int io_uring_mmap(int fd, struct io_uring_params *p,
+ struct io_uring_sq *sq, struct io_uring_cq *cq)
+{
+ size_t size;
+ void *ptr;
+ int ret;
+
+ sq->ring_sz = p->sq_off.array + p->sq_entries * sizeof(unsigned);
+ ptr = mmap(0, sq->ring_sz, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_SQ_RING);
+ if (ptr == MAP_FAILED)
+ return -errno;
+ sq->khead = ptr + p->sq_off.head;
+ sq->ktail = ptr + p->sq_off.tail;
+ sq->kring_mask = ptr + p->sq_off.ring_mask;
+ sq->kring_entries = ptr + p->sq_off.ring_entries;
+ sq->kflags = ptr + p->sq_off.flags;
+ sq->kdropped = ptr + p->sq_off.dropped;
+ sq->array = ptr + p->sq_off.array;
+
+ size = p->sq_entries * sizeof(struct io_uring_sqe),
+ sq->sqes = mmap(0, size, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, fd,
+ IORING_OFF_SQES);
+ if (sq->sqes == MAP_FAILED) {
+ ret = -errno;
+err:
+ munmap(sq->khead, sq->ring_sz);
+ return ret;
+ }
+
+ cq->ring_sz = p->cq_off.cqes + p->cq_entries * sizeof(struct io_uring_cqe);
+ ptr = mmap(0, cq->ring_sz, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_CQ_RING);
+ if (ptr == MAP_FAILED) {
+ ret = -errno;
+ munmap(sq->sqes, p->sq_entries * sizeof(struct io_uring_sqe));
+ goto err;
+ }
+ cq->khead = ptr + p->cq_off.head;
+ cq->ktail = ptr + p->cq_off.tail;
+ cq->kring_mask = ptr + p->cq_off.ring_mask;
+ cq->kring_entries = ptr + p->cq_off.ring_entries;
+ cq->koverflow = ptr + p->cq_off.overflow;
+ cq->cqes = ptr + p->cq_off.cqes;
+ return 0;
+}
+
+/*
+ * For users that want to specify sq_thread_cpu or sq_thread_idle, this
+ * interface is a convenient helper for mmap()ing the rings.
+ * Returns -1 on error, or zero on success. On success, 'ring'
+ * contains the necessary information to read/write to the rings.
+ */
+int io_uring_queue_mmap(int fd, struct io_uring_params *p, struct io_uring *ring)
+{
+ int ret;
+
+ memset(ring, 0, sizeof(*ring));
+ ret = io_uring_mmap(fd, p, &ring->sq, &ring->cq);
+ if (!ret)
+ ring->ring_fd = fd;
+ return ret;
+}
+
+/*
+ * Returns -1 on error, or zero on success. On success, 'ring'
+ * contains the necessary information to read/write to the rings.
+ */
+int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags)
+{
+ struct io_uring_params p;
+ int fd;
+
+ memset(&p, 0, sizeof(p));
+ p.flags = flags;
+
+ fd = io_uring_setup(entries, &p);
+ if (fd < 0)
+ return fd;
+
+ return io_uring_queue_mmap(fd, &p, ring);
+}
+
+void io_uring_queue_exit(struct io_uring *ring)
+{
+ struct io_uring_sq *sq = &ring->sq;
+ struct io_uring_cq *cq = &ring->cq;
+
+ munmap(sq->sqes, *sq->kring_entries * sizeof(struct io_uring_sqe));
+ munmap(sq->khead, sq->ring_sz);
+ munmap(cq->khead, cq->ring_sz);
+ close(ring->ring_fd);
+}
diff --git a/tools/io_uring/syscall.c b/tools/io_uring/syscall.c
new file mode 100644
index 000000000000..6b835e5c6a5b
--- /dev/null
+++ b/tools/io_uring/syscall.c
@@ -0,0 +1,40 @@
+/*
+ * Will go away once libc support is there
+ */
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/uio.h>
+#include <signal.h>
+#include "liburing.h"
+
+#if defined(__x86_64) || defined(__i386__)
+#ifndef __NR_sys_io_uring_setup
+#define __NR_sys_io_uring_setup 425
+#endif
+#ifndef __NR_sys_io_uring_enter
+#define __NR_sys_io_uring_enter 426
+#endif
+#ifndef __NR_sys_io_uring_register
+#define __NR_sys_io_uring_register 427
+#endif
+#else
+#error "Arch not supported yet"
+#endif
+
+int io_uring_register(int fd, unsigned int opcode, void *arg,
+ unsigned int nr_args)
+{
+ return syscall(__NR_sys_io_uring_register, fd, opcode, arg, nr_args);
+}
+
+int io_uring_setup(unsigned entries, struct io_uring_params *p)
+{
+ return syscall(__NR_sys_io_uring_setup, entries, p);
+}
+
+int io_uring_enter(unsigned fd, unsigned to_submit, unsigned min_complete,
+ unsigned flags, sigset_t *sig)
+{
+ return syscall(__NR_sys_io_uring_enter, fd, to_submit, min_complete,
+ flags, sig, _NSIG / 8);
+}