[fio.git] / engines / libaio.c

/*
 * libaio engine
 *
 * IO engine using the Linux native aio interface.
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <libaio.h>

#include "../fio.h"
#include "../lib/pow2.h"

static int fio_libaio_commit(struct thread_data *td);

struct libaio_data {
	io_context_t aio_ctx;
	struct io_event *aio_events;
	struct iocb **iocbs;
	struct io_u **io_us;

	/*
	 * Basic ring buffer. 'head' is incremented in _queue(), and
	 * 'tail' is incremented in _commit(). We keep 'queued' so
	 * that we know if the ring is full or empty, when
	 * 'head' == 'tail'. 'entries' is the ring size, and
	 * 'is_pow2' is just an optimization to use AND instead of
	 * modulus to get the remainder on ring increment.
	 */
	int is_pow2;
	unsigned int entries;
	unsigned int queued;
	unsigned int head;
	unsigned int tail;
};

struct libaio_options {
	void *pad;
	unsigned int userspace_reap;
};

static struct fio_option options[] = {
	{
		.name	= "userspace_reap",
		.lname	= "Libaio userspace reaping",
		.type	= FIO_OPT_STR_SET,
		.off1	= offsetof(struct libaio_options, userspace_reap),
		.help	= "Use alternative user-space reap implementation",
		.category = FIO_OPT_C_ENGINE,
		.group	= FIO_OPT_G_LIBAIO,
	},
	{
		.name	= NULL,
	},
};

static inline void ring_inc(struct libaio_data *ld, unsigned int *val,
			    unsigned int add)
{
	if (ld->is_pow2)
		*val = (*val + add) & (ld->entries - 1);
	else
		*val = (*val + add) % ld->entries;
}

static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)
{
	struct fio_file *f = io_u->file;

	if (io_u->ddir == DDIR_READ)
		io_prep_pread(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
	else if (io_u->ddir == DDIR_WRITE)
		io_prep_pwrite(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
	else if (ddir_sync(io_u->ddir))
		io_prep_fsync(&io_u->iocb, f->fd);

	return 0;
}

static struct io_u *fio_libaio_event(struct thread_data *td, int event)
{
	struct libaio_data *ld = td->io_ops->data;
	struct io_event *ev;
	struct io_u *io_u;

	ev = ld->aio_events + event;
	io_u = container_of(ev->obj, struct io_u, iocb);

	if (ev->res != io_u->xfer_buflen) {
		if (ev->res > io_u->xfer_buflen)
			io_u->error = -ev->res;
		else
			io_u->resid = io_u->xfer_buflen - ev->res;
	} else
		io_u->error = 0;

	return io_u;
}

struct aio_ring {
	unsigned id;		 /** kernel internal index number */
	unsigned nr;		 /** number of io_events */
	unsigned head;
	unsigned tail;

	unsigned magic;
	unsigned compat_features;
	unsigned incompat_features;
	unsigned header_length;	/** size of aio_ring */

	struct io_event events[0];
};

#define AIO_RING_MAGIC	0xa10a10a1

static int user_io_getevents(io_context_t aio_ctx, unsigned int max,
			     struct io_event *events)
{
	long i = 0;
	unsigned head;
	struct aio_ring *ring = (struct aio_ring*) aio_ctx;

	while (i < max) {
		head = ring->head;

		if (head == ring->tail) {
			/* There are no more completions */
			break;
		} else {
			/* There is another completion to reap */
			events[i] = ring->events[head];
			read_barrier();
			ring->head = (head + 1) % ring->nr;
			i++;
		}
	}

	return i;
}

static int fio_libaio_getevents(struct thread_data *td, unsigned int min,
				unsigned int max, const struct timespec *t)
{
	struct libaio_data *ld = td->io_ops->data;
	struct libaio_options *o = td->eo;
	unsigned actual_min = td->o.iodepth_batch_complete == 0 ? 0 : min;
	struct timespec __lt, *lt = NULL;
	int r, events = 0;

	if (t) {
		__lt = *t;
		lt = &__lt;
	}

	do {
		if (o->userspace_reap == 1
		    && actual_min == 0
		    && ((struct aio_ring *)(ld->aio_ctx))->magic
				== AIO_RING_MAGIC) {
			r = user_io_getevents(ld->aio_ctx, max,
				ld->aio_events + events);
		} else {
			r = io_getevents(ld->aio_ctx, actual_min,
				max, ld->aio_events + events, lt);
		}
		if (r > 0)
			events += r;
		else if ((min && r == 0) || r == -EAGAIN) {
			fio_libaio_commit(td);
			usleep(100);
		} else if (r != -EINTR)
			break;
	} while (events < min);

	return r < 0 ? r : events;
}

static int fio_libaio_queue(struct thread_data *td, struct io_u *io_u)
{
	struct libaio_data *ld = td->io_ops->data;

	fio_ro_check(td, io_u);

	if (ld->queued == td->o.iodepth)
		return FIO_Q_BUSY;

	/*
	 * fsync is tricky, since it can fail and we need to do it
	 * serialized with other io. the reason is that linux doesn't
	 * support aio fsync yet. So return busy for the case where we
	 * have pending io, to let fio complete those first.
	 */
	if (ddir_sync(io_u->ddir)) {
		if (ld->queued)
			return FIO_Q_BUSY;

		do_io_u_sync(td, io_u);
		return FIO_Q_COMPLETED;
	}

	if (io_u->ddir == DDIR_TRIM) {
		if (ld->queued)
			return FIO_Q_BUSY;

		do_io_u_trim(td, io_u);
		return FIO_Q_COMPLETED;
	}

	ld->iocbs[ld->head] = &io_u->iocb;
	ld->io_us[ld->head] = io_u;
	ring_inc(ld, &ld->head, 1);
	ld->queued++;
	return FIO_Q_QUEUED;
}

static void fio_libaio_queued(struct thread_data *td, struct io_u **io_us,
			      unsigned int nr)
{
	struct timeval now;
	unsigned int i;

	if (!fio_fill_issue_time(td))
		return;

	fio_gettime(&now, NULL);

	for (i = 0; i < nr; i++) {
		struct io_u *io_u = io_us[i];

		memcpy(&io_u->issue_time, &now, sizeof(now));
		io_u_queued(td, io_u);
	}
}

static int fio_libaio_commit(struct thread_data *td)
{
	struct libaio_data *ld = td->io_ops->data;
	struct iocb **iocbs;
	struct io_u **io_us;
	struct timeval tv;
	int ret, wait_start = 0;

	if (!ld->queued)
		return 0;

	do {
		long nr = ld->queued;

		nr = min((unsigned int) nr, ld->entries - ld->tail);
		io_us = ld->io_us + ld->tail;
		iocbs = ld->iocbs + ld->tail;

		ret = io_submit(ld->aio_ctx, nr, iocbs);
		if (ret > 0) {
			fio_libaio_queued(td, io_us, ret);
			io_u_mark_submit(td, ret);

			ld->queued -= ret;
			ring_inc(ld, &ld->tail, ret);
			ret = 0;
			wait_start = 0;
		} else if (ret == -EINTR || !ret) {
			if (!ret)
				io_u_mark_submit(td, ret);
			wait_start = 0;
			continue;
		} else if (ret == -EAGAIN) {
			/*
			 * If we get EAGAIN, we should break out without
			 * error and let the upper layer reap some
			 * events for us. If we have no queued IO, we
			 * must loop here. If we loop for more than 30s,
			 * just error out, something must be buggy in the
			 * IO path.
			 */
			if (ld->queued) {
				ret = 0;
				break;
			}
			if (!wait_start) {
				fio_gettime(&tv, NULL);
				wait_start = 1;
			} else if (mtime_since_now(&tv) > 30000) {
				log_err("fio: aio appears to be stalled, giving up\n");
				break;
			}
			usleep(1);
			continue;
		} else if (ret == -ENOMEM) {
			/*
			 * If we get -ENOMEM, reap events if we can. If
			 * we cannot, treat it as a fatal event since there's
			 * nothing we can do about it.
			 */
			if (ld->queued)
				ret = 0;
			break;
		} else
			break;
	} while (ld->queued);

	return ret;
}

static int fio_libaio_cancel(struct thread_data *td, struct io_u *io_u)
{
	struct libaio_data *ld = td->io_ops->data;

	return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);
}

static void fio_libaio_cleanup(struct thread_data *td)
{
	struct libaio_data *ld = td->io_ops->data;

	if (ld) {
		/*
		 * Work-around to avoid huge RCU stalls at exit time. If we
		 * don't do this here, then it'll be torn down by exit_aio().
		 * But for that case we can parallellize the freeing, thus
		 * speeding it up a lot.
		 */
		if (!(td->flags & TD_F_CHILD))
			io_destroy(ld->aio_ctx);
		free(ld->aio_events);
		free(ld->iocbs);
		free(ld->io_us);
		free(ld);
	}
}

static int fio_libaio_init(struct thread_data *td)
{
	struct libaio_options *o = td->eo;
	struct libaio_data *ld;
	int err = 0;

	ld = calloc(1, sizeof(*ld));

	/*
	 * First try passing in 0 for queue depth, since we don't
	 * care about the user ring. If that fails, the kernel is too old
	 * and we need the right depth.
	 */
	if (!o->userspace_reap)
		err = io_queue_init(INT_MAX, &ld->aio_ctx);
	if (o->userspace_reap || err == -EINVAL)
		err = io_queue_init(td->o.iodepth, &ld->aio_ctx);
	if (err) {
		td_verror(td, -err, "io_queue_init");
		log_err("fio: check /proc/sys/fs/aio-max-nr\n");
		free(ld);
		return 1;
	}

	ld->entries = td->o.iodepth;
	ld->is_pow2 = is_power_of_2(ld->entries);
	ld->aio_events = calloc(ld->entries, sizeof(struct io_event));
	ld->iocbs = calloc(ld->entries, sizeof(struct iocb *));
	ld->io_us = calloc(ld->entries, sizeof(struct io_u *));

	td->io_ops->data = ld;
	return 0;
}

static struct ioengine_ops ioengine = {
	.name			= "libaio",
	.version		= FIO_IOOPS_VERSION,
	.init			= fio_libaio_init,
	.prep			= fio_libaio_prep,
	.queue			= fio_libaio_queue,
	.commit			= fio_libaio_commit,
	.cancel			= fio_libaio_cancel,
	.getevents		= fio_libaio_getevents,
	.event			= fio_libaio_event,
	.cleanup		= fio_libaio_cleanup,
	.open_file		= generic_open_file,
	.close_file		= generic_close_file,
	.get_file_size		= generic_get_file_size,
	.options		= options,
	.option_struct_size	= sizeof(struct libaio_options),
};

static void fio_init fio_libaio_register(void)
{
	register_ioengine(&ioengine);
}

static void fio_exit fio_libaio_unregister(void)
{
	unregister_ioengine(&ioengine);
}
Commit	Line	Data
	1	/*
	2	* libaio engine
	3	*
	4	* IO engine using the Linux native aio interface.
	5	*
	6	*/
	7	#include <stdio.h>
	8	#include <stdlib.h>
	9	#include <unistd.h>
	10	#include <errno.h>
	11	#include <assert.h>
	12	#include <libaio.h>
	13
	14	#include "../fio.h"
	15	#include "../lib/pow2.h"
	16
	17	static int fio_libaio_commit(struct thread_data *td);
	18
	19	struct libaio_data {
	20	io_context_t aio_ctx;
	21	struct io_event *aio_events;
	22	struct iocb **iocbs;
	23	struct io_u **io_us;
	24
	25	/*
	26	* Basic ring buffer. 'head' is incremented in _queue(), and
	27	* 'tail' is incremented in _commit(). We keep 'queued' so
	28	* that we know if the ring is full or empty, when
	29	* 'head' == 'tail'. 'entries' is the ring size, and
	30	* 'is_pow2' is just an optimization to use AND instead of
	31	* modulus to get the remainder on ring increment.
	32	*/
	33	int is_pow2;
	34	unsigned int entries;
	35	unsigned int queued;
	36	unsigned int head;
	37	unsigned int tail;
	38	};
	39
	40	struct libaio_options {
	41	void *pad;
	42	unsigned int userspace_reap;
	43	};
	44
	45	static struct fio_option options[] = {
	46	{
	47	.name = "userspace_reap",
	48	.lname = "Libaio userspace reaping",
	49	.type = FIO_OPT_STR_SET,
	50	.off1 = offsetof(struct libaio_options, userspace_reap),
	51	.help = "Use alternative user-space reap implementation",
	52	.category = FIO_OPT_C_ENGINE,
	53	.group = FIO_OPT_G_LIBAIO,
	54	},
	55	{
	56	.name = NULL,
	57	},
	58	};
	59
	60	static inline void ring_inc(struct libaio_data ld, unsigned int val,
	61	unsigned int add)
	62	{
	63	if (ld->is_pow2)
	64	val = (val + add) & (ld->entries - 1);
	65	else
	66	val = (val + add) % ld->entries;
	67	}
	68
	69	static int fio_libaio_prep(struct thread_data fio_unused td, struct io_u io_u)
	70	{
	71	struct fio_file *f = io_u->file;
	72
	73	if (io_u->ddir == DDIR_READ)
	74	io_prep_pread(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
	75	else if (io_u->ddir == DDIR_WRITE)
	76	io_prep_pwrite(&io_u->iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
	77	else if (ddir_sync(io_u->ddir))
	78	io_prep_fsync(&io_u->iocb, f->fd);
	79
	80	return 0;
	81	}
	82
	83	static struct io_u fio_libaio_event(struct thread_data td, int event)
	84	{
	85	struct libaio_data *ld = td->io_ops->data;
	86	struct io_event *ev;
	87	struct io_u *io_u;
	88
	89	ev = ld->aio_events + event;
	90	io_u = container_of(ev->obj, struct io_u, iocb);
	91
	92	if (ev->res != io_u->xfer_buflen) {
	93	if (ev->res > io_u->xfer_buflen)
	94	io_u->error = -ev->res;
	95	else
	96	io_u->resid = io_u->xfer_buflen - ev->res;
	97	} else
	98	io_u->error = 0;
	99
	100	return io_u;
	101	}
	102
	103	struct aio_ring {
	104	unsigned id; /** kernel internal index number */
	105	unsigned nr; /** number of io_events */
	106	unsigned head;
	107	unsigned tail;
	108
	109	unsigned magic;
	110	unsigned compat_features;
	111	unsigned incompat_features;
	112	unsigned header_length; /** size of aio_ring */
	113
	114	struct io_event events[0];
	115	};
	116
	117	#define AIO_RING_MAGIC 0xa10a10a1
	118
	119	static int user_io_getevents(io_context_t aio_ctx, unsigned int max,
	120	struct io_event *events)
	121	{
	122	long i = 0;
	123	unsigned head;
	124	struct aio_ring ring = (struct aio_ring) aio_ctx;
	125
	126	while (i < max) {
	127	head = ring->head;
	128
	129	if (head == ring->tail) {
	130	/* There are no more completions */
	131	break;
	132	} else {
	133	/* There is another completion to reap */
	134	events[i] = ring->events[head];
	135	read_barrier();
	136	ring->head = (head + 1) % ring->nr;
	137	i++;
	138	}
	139	}
	140
	141	return i;
	142	}
	143
	144	static int fio_libaio_getevents(struct thread_data *td, unsigned int min,
	145	unsigned int max, const struct timespec *t)
	146	{
	147	struct libaio_data *ld = td->io_ops->data;
	148	struct libaio_options *o = td->eo;
	149	unsigned actual_min = td->o.iodepth_batch_complete == 0 ? 0 : min;
	150	struct timespec __lt, *lt = NULL;
	151	int r, events = 0;
	152
	153	if (t) {
	154	__lt = *t;
	155	lt = &__lt;
	156	}
	157
	158	do {
	159	if (o->userspace_reap == 1
	160	&& actual_min == 0
	161	&& ((struct aio_ring *)(ld->aio_ctx))->magic
	162	== AIO_RING_MAGIC) {
	163	r = user_io_getevents(ld->aio_ctx, max,
	164	ld->aio_events + events);
	165	} else {
	166	r = io_getevents(ld->aio_ctx, actual_min,
	167	max, ld->aio_events + events, lt);
	168	}
	169	if (r > 0)
	170	events += r;
	171	else if ((min && r == 0) \|\| r == -EAGAIN) {
	172	fio_libaio_commit(td);
	173	usleep(100);
	174	} else if (r != -EINTR)
	175	break;
	176	} while (events < min);
	177
	178	return r < 0 ? r : events;
	179	}
	180
	181	static int fio_libaio_queue(struct thread_data td, struct io_u io_u)
	182	{
	183	struct libaio_data *ld = td->io_ops->data;
	184
	185	fio_ro_check(td, io_u);
	186
	187	if (ld->queued == td->o.iodepth)
	188	return FIO_Q_BUSY;
	189
	190	/*
	191	* fsync is tricky, since it can fail and we need to do it
	192	* serialized with other io. the reason is that linux doesn't
	193	* support aio fsync yet. So return busy for the case where we
	194	* have pending io, to let fio complete those first.
	195	*/
	196	if (ddir_sync(io_u->ddir)) {
	197	if (ld->queued)
	198	return FIO_Q_BUSY;
	199
	200	do_io_u_sync(td, io_u);
	201	return FIO_Q_COMPLETED;
	202	}
	203
	204	if (io_u->ddir == DDIR_TRIM) {
	205	if (ld->queued)
	206	return FIO_Q_BUSY;
	207
	208	do_io_u_trim(td, io_u);
	209	return FIO_Q_COMPLETED;
	210	}
	211
	212	ld->iocbs[ld->head] = &io_u->iocb;
	213	ld->io_us[ld->head] = io_u;
	214	ring_inc(ld, &ld->head, 1);
	215	ld->queued++;
	216	return FIO_Q_QUEUED;
	217	}
	218
	219	static void fio_libaio_queued(struct thread_data td, struct io_u *io_us,
	220	unsigned int nr)
	221	{
	222	struct timeval now;
	223	unsigned int i;
	224
	225	if (!fio_fill_issue_time(td))
	226	return;
	227
	228	fio_gettime(&now, NULL);
	229
	230	for (i = 0; i < nr; i++) {
	231	struct io_u *io_u = io_us[i];
	232
	233	memcpy(&io_u->issue_time, &now, sizeof(now));
	234	io_u_queued(td, io_u);
	235	}
	236	}
	237
	238	static int fio_libaio_commit(struct thread_data *td)
	239	{
	240	struct libaio_data *ld = td->io_ops->data;
	241	struct iocb **iocbs;
	242	struct io_u **io_us;
	243	struct timeval tv;
	244	int ret, wait_start = 0;
	245
	246	if (!ld->queued)
	247	return 0;
	248
	249	do {
	250	long nr = ld->queued;
	251
	252	nr = min((unsigned int) nr, ld->entries - ld->tail);
	253	io_us = ld->io_us + ld->tail;
	254	iocbs = ld->iocbs + ld->tail;
	255
	256	ret = io_submit(ld->aio_ctx, nr, iocbs);
	257	if (ret > 0) {
	258	fio_libaio_queued(td, io_us, ret);
	259	io_u_mark_submit(td, ret);
	260
	261	ld->queued -= ret;
	262	ring_inc(ld, &ld->tail, ret);
	263	ret = 0;
	264	wait_start = 0;
	265	} else if (ret == -EINTR \|\| !ret) {
	266	if (!ret)
	267	io_u_mark_submit(td, ret);
	268	wait_start = 0;
	269	continue;
	270	} else if (ret == -EAGAIN) {
	271	/*
	272	* If we get EAGAIN, we should break out without
	273	* error and let the upper layer reap some
	274	* events for us. If we have no queued IO, we
	275	* must loop here. If we loop for more than 30s,
	276	* just error out, something must be buggy in the
	277	* IO path.
	278	*/
	279	if (ld->queued) {
	280	ret = 0;
	281	break;
	282	}
	283	if (!wait_start) {
	284	fio_gettime(&tv, NULL);
	285	wait_start = 1;
	286	} else if (mtime_since_now(&tv) > 30000) {
	287	log_err("fio: aio appears to be stalled, giving up\n");
	288	break;
	289	}
	290	usleep(1);
	291	continue;
	292	} else if (ret == -ENOMEM) {
	293	/*
	294	* If we get -ENOMEM, reap events if we can. If
	295	* we cannot, treat it as a fatal event since there's
	296	* nothing we can do about it.
	297	*/
	298	if (ld->queued)
	299	ret = 0;
	300	break;
	301	} else
	302	break;
	303	} while (ld->queued);
	304
	305	return ret;
	306	}
	307
	308	static int fio_libaio_cancel(struct thread_data td, struct io_u io_u)
	309	{
	310	struct libaio_data *ld = td->io_ops->data;
	311
	312	return io_cancel(ld->aio_ctx, &io_u->iocb, ld->aio_events);
	313	}
	314
	315	static void fio_libaio_cleanup(struct thread_data *td)
	316	{
	317	struct libaio_data *ld = td->io_ops->data;
	318
	319	if (ld) {
	320	/*
	321	* Work-around to avoid huge RCU stalls at exit time. If we
	322	* don't do this here, then it'll be torn down by exit_aio().
	323	* But for that case we can parallellize the freeing, thus
	324	* speeding it up a lot.
	325	*/
	326	if (!(td->flags & TD_F_CHILD))
	327	io_destroy(ld->aio_ctx);
	328	free(ld->aio_events);
	329	free(ld->iocbs);
	330	free(ld->io_us);
	331	free(ld);
	332	}
	333	}
	334
	335	static int fio_libaio_init(struct thread_data *td)
	336	{
	337	struct libaio_options *o = td->eo;
	338	struct libaio_data *ld;
	339	int err = 0;
	340
	341	ld = calloc(1, sizeof(*ld));
	342
	343	/*
	344	* First try passing in 0 for queue depth, since we don't
	345	* care about the user ring. If that fails, the kernel is too old
	346	* and we need the right depth.
	347	*/
	348	if (!o->userspace_reap)
	349	err = io_queue_init(INT_MAX, &ld->aio_ctx);
	350	if (o->userspace_reap \|\| err == -EINVAL)
	351	err = io_queue_init(td->o.iodepth, &ld->aio_ctx);
	352	if (err) {
	353	td_verror(td, -err, "io_queue_init");
	354	log_err("fio: check /proc/sys/fs/aio-max-nr\n");
	355	free(ld);
	356	return 1;
	357	}
	358
	359	ld->entries = td->o.iodepth;
	360	ld->is_pow2 = is_power_of_2(ld->entries);
	361	ld->aio_events = calloc(ld->entries, sizeof(struct io_event));
	362	ld->iocbs = calloc(ld->entries, sizeof(struct iocb *));
	363	ld->io_us = calloc(ld->entries, sizeof(struct io_u *));
	364
	365	td->io_ops->data = ld;
	366	return 0;
	367	}
	368
	369	static struct ioengine_ops ioengine = {
	370	.name = "libaio",
	371	.version = FIO_IOOPS_VERSION,
	372	.init = fio_libaio_init,
	373	.prep = fio_libaio_prep,
	374	.queue = fio_libaio_queue,
	375	.commit = fio_libaio_commit,
	376	.cancel = fio_libaio_cancel,
	377	.getevents = fio_libaio_getevents,
	378	.event = fio_libaio_event,
	379	.cleanup = fio_libaio_cleanup,
	380	.open_file = generic_open_file,
	381	.close_file = generic_close_file,
	382	.get_file_size = generic_get_file_size,
	383	.options = options,
	384	.option_struct_size = sizeof(struct libaio_options),
	385	};
	386
	387	static void fio_init fio_libaio_register(void)
	388	{
	389	register_ioengine(&ioengine);
	390	}
	391
	392	static void fio_exit fio_libaio_unregister(void)
	393	{
	394	unregister_ioengine(&ioengine);
	395	}