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>

1 files changed, 616 insertions, 0 deletions

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;
+}