X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=engines%2Flibaio.c;h=f7e2f8967c8900a1d5c6839dda1d746df5986b60;hp=cb488efb1b5acbbd524bbc25914f40b86ea772e7;hb=d36b072de874db57b585993c6c3b475f34ecad58;hpb=22819ec237297fc39435ed566bee01a4225bfb39

diff --git a/engines/libaio.c b/engines/libaio.c
index cb488efb..f7e2f896 100644
--- a/engines/libaio.c
+++ b/engines/libaio.c
@@ -1,5 +1,7 @@
 /*
- * native linux aio io engine
+ * libaio engine
+ *
+ * IO engine using the Linux native aio interface.
  *
  */
 #include <stdio.h>
@@ -7,19 +9,62 @@
 #include <unistd.h>
 #include <errno.h>
 #include <assert.h>
+#include <libaio.h>
 
 #include "../fio.h"
-#include "../os.h"
-
-#ifdef FIO_HAVE_LIBAIO
 
-#define ev_to_iou(ev)	(struct io_u *) ((unsigned long) (ev)->obj)
+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 {
+	struct thread_data *td;
+	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;
@@ -28,10 +73,8 @@ static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)
 		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 (io_u->ddir == DDIR_SYNC)
+	else if (ddir_sync(io_u->ddir))
 		io_prep_fsync(&io_u->iocb, f->fd);
-	else
-		return 1;
 
 	return 0;
 }
@@ -39,69 +82,224 @@ static int fio_libaio_prep(struct thread_data fio_unused *td, struct io_u *io_u)
 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;
 
-	return ev_to_iou(ld->aio_events + event);
+		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, int min, int max,
-				struct timespec *t)
+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;
-	long r;
+	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 {
-		r = io_getevents(ld->aio_ctx, min, max, ld->aio_events, t);
-		if (r >= min)
-			break;
-		else if (r == -EAGAIN) {
+		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);
-			continue;
-		} else if (r == -EINTR)
-			continue;
-		else if (r != 0)
+		} else if (r != -EINTR)
 			break;
-	} while (1);
+	} while (events < min);
 
-	return r;
+	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;
-	struct iocb *iocb = &io_u->iocb;
-	long ret;
+
+	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 {
-		ret = io_submit(ld->aio_ctx, 1, &iocb);
-		if (ret == 1)
-			return FIO_Q_QUEUED;
-		else if (ret == -EAGAIN || !ret)
-			usleep(100);
-		else if (ret == -EINTR)
+		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 == -EINVAL && io_u->ddir == DDIR_SYNC) {
+		} else if (ret == -EAGAIN) {
 			/*
-			 * the async fsync doesn't currently seem to be
-			 * supported, so just fsync if we fail with EINVAL
-			 * for a sync. since buffered io is also sync
-			 * with libaio (still), we don't have pending
-			 * requests to flush first.
+			 * 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 (fsync(io_u->file->fd) < 0)
-				ret = -errno;
-			else
-				ret = FIO_Q_COMPLETED;
+			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 (1);
-
-	if (ret <= 0) {
-		io_u->resid = io_u->xfer_buflen;
-		io_u->error = -ret;
-		td_verror(td, io_u->error);
-		return FIO_Q_COMPLETED;
-	}
+	} while (ld->queued);
 
 	return ret;
 }
@@ -119,64 +317,65 @@ static void fio_libaio_cleanup(struct thread_data *td)
 
 	if (ld) {
 		io_destroy(ld->aio_ctx);
-		if (ld->aio_events)
-			free(ld->aio_events);
-
+		free(ld->aio_events);
+		free(ld->iocbs);
+		free(ld->io_us);
 		free(ld);
-		td->io_ops->data = NULL;
 	}
 }
 
 static int fio_libaio_init(struct thread_data *td)
 {
-	struct libaio_data *ld = malloc(sizeof(*ld));
+	struct libaio_options *o = td->eo;
+	struct libaio_data *ld;
+	int err = 0;
 
-	memset(ld, 0, sizeof(*ld));
-	if (io_queue_init(td->iodepth, &ld->aio_ctx)) {
-		td_verror(td, errno);
+	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->aio_events = malloc(td->iodepth * sizeof(struct io_event));
-	memset(ld->aio_events, 0, td->iodepth * sizeof(struct io_event));
+	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,
-	.cancel		= fio_libaio_cancel,
-	.getevents	= fio_libaio_getevents,
-	.event		= fio_libaio_event,
-	.cleanup	= fio_libaio_cleanup,
+	.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),
 };
 
-#else /* FIO_HAVE_LIBAIO */
-
-/*
- * When we have a proper configure system in place, we simply wont build
- * and install this io engine. For now install a crippled version that
- * just complains and fails to load.
- */
-static int fio_libaio_init(struct thread_data fio_unused *td)
-{
-	fprintf(stderr, "fio: libaio not available\n");
-	return 1;
-}
-
-static struct ioengine_ops ioengine = {
-	.name		= "libaio",
-	.version	= FIO_IOOPS_VERSION,
-	.init		= fio_libaio_init,
-};
-
-#endif
-
 static void fio_init fio_libaio_register(void)
 {
 	register_ioengine(&ioengine);