X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=io_u.c;h=7890a87099c26f7d5802f9a0479e8ddc6d768bad;hp=c04c9de06572f4cbddc476d36f6282eb1913fa80;hb=564ca97254984165e06d5fd4b1270bac95ca55fb;hpb=9978463287982c2f73f171ec9a79979939dee47a

diff --git a/io_u.c b/io_u.c
index c04c9de0..7890a870 100644
--- a/io_u.c
+++ b/io_u.c
@@ -3,13 +3,17 @@
 #include <string.h>
 #include <signal.h>
 #include <time.h>
+#include <assert.h>
 
 #include "fio.h"
-#include "os.h"
+
+/*
+ * Change this define to play with the timeout handling
+ */
+#undef FIO_USE_TIMEOUT
 
 struct io_completion_data {
 	int nr;				/* input */
-	endio_handler *handler;		/* input */
 
 	int error;			/* output */
 	unsigned long bytes_done[2];	/* output */
@@ -32,10 +36,10 @@ static int random_map_free(struct thread_data *td, struct fio_file *f,
 /*
  * Mark a given offset as used in the map.
  */
-static void mark_random_map(struct thread_data *td, struct fio_file *f,
-			    struct io_u *io_u)
+static void mark_random_map(struct thread_data *td, struct io_u *io_u)
 {
-	unsigned int min_bs = td->rw_min_bs;
+	unsigned int min_bs = td->o.rw_min_bs;
+	struct fio_file *f = io_u->file;
 	unsigned long long block;
 	unsigned int blocks;
 	unsigned int nr_blocks;
@@ -47,7 +51,11 @@ static void mark_random_map(struct thread_data *td, struct fio_file *f,
 	while (blocks < nr_blocks) {
 		unsigned int idx, bit;
 
-		if (!random_map_free(td, f, block))
+		/*
+		 * If we have a mixed random workload, we may
+		 * encounter blocks we already did IO to.
+		 */
+		if (!td->o.ddir_nr == 1 && !random_map_free(td, f, block))
 			break;
 
 		idx = RAND_MAP_IDX(td, f, block);
@@ -74,9 +82,9 @@ static int get_next_free_block(struct thread_data *td, struct fio_file *f,
 
 	i = f->last_free_lookup;
 	*b = (i * BLOCKS_PER_MAP);
-	while ((*b) * td->rw_min_bs < f->real_file_size) {
+	while ((*b) * td->o.rw_min_bs < f->real_file_size) {
 		if (f->file_map[i] != -1UL) {
-			*b += ffz(f->file_map[i]);
+			*b += fio_ffz(f->file_map[i]);
 			f->last_free_lookup = i;
 			return 0;
 		}
@@ -88,73 +96,150 @@ static int get_next_free_block(struct thread_data *td, struct fio_file *f,
 	return 1;
 }
 
+static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
+				int ddir, unsigned long long *b)
+{
+	unsigned long long max_blocks = f->io_size / td->o.min_bs[ddir];
+	unsigned long long r, rb;
+	int loops = 5;
+
+	do {
+		r = os_random_long(&td->random_state);
+		if (!max_blocks)
+			*b = 0;
+		else
+			*b = ((max_blocks - 1) * r / (unsigned long long) (RAND_MAX+1.0));
+		/*
+		 * if we are not maintaining a random map, we are done.
+		 */
+		if (td->o.norandommap)
+			return 0;
+
+		/*
+		 * calculate map offset and chec if it's free
+		 */
+		rb = *b + (f->file_offset / td->o.min_bs[ddir]);
+		if (random_map_free(td, f, rb))
+			return 0;
+
+	} while (--loops);
+
+	/*
+	 * we get here, if we didn't suceed in looking up a block. generate
+	 * a random start offset into the filemap, and find the first free
+	 * block from there.
+	 */
+	loops = 10;
+	do {
+		f->last_free_lookup = (f->num_maps - 1) * (r / (RAND_MAX+1.0));
+		if (!get_next_free_block(td, f, b))
+			return 0;
+
+		r = os_random_long(&td->random_state);
+	} while (--loops);
+
+	/*
+	 * that didn't work either, try exhaustive search from the start
+	 */
+	f->last_free_lookup = 0;
+	return get_next_free_block(td, f, b);
+}
+
 /*
  * For random io, generate a random new block and see if it's used. Repeat
  * until we find a free one. For sequential io, just return the end of
  * the last io issued.
  */
-static int get_next_offset(struct thread_data *td, struct fio_file *f,
-			   struct io_u *io_u)
+static int get_next_offset(struct thread_data *td, struct io_u *io_u)
 {
+	struct fio_file *f = io_u->file;
 	const int ddir = io_u->ddir;
-	unsigned long long b, rb;
-	long r;
-
-	if (!td->sequential) {
-		unsigned long long max_blocks = f->file_size / td->min_bs[ddir];
-		int loops = 5;
+	unsigned long long b;
 
-		do {
-			r = os_random_long(&td->random_state);
-			b = ((max_blocks - 1) * r / (unsigned long long) (RAND_MAX+1.0));
-			if (td->norandommap)
-				break;
-			rb = b + (f->file_offset / td->min_bs[ddir]);
-			loops--;
-		} while (!random_map_free(td, f, rb) && loops);
+	if (td_random(td) && (td->o.ddir_nr && !--td->ddir_nr)) {
+		td->ddir_nr = td->o.ddir_nr;
 
-		/*
-		 * if we failed to retrieve a truly random offset within
-		 * the loops assigned, see if there are free ones left at all
-		 */
-		if (!loops && get_next_free_block(td, f, &b))
+		if (get_next_rand_offset(td, f, ddir, &b))
 			return 1;
-	} else
-		b = f->last_pos / td->min_bs[ddir];
+	} else {
+		if (f->last_pos >= f->real_file_size) {
+			if (!td_random(td) || get_next_rand_offset(td, f, ddir, &b))
+				return 1;
+		} else
+			b = (f->last_pos - f->file_offset) / td->o.min_bs[ddir];
+	}
 
-	io_u->offset = (b * td->min_bs[ddir]) + f->file_offset;
+	io_u->offset = (b * td->o.min_bs[ddir]) + f->file_offset;
 	if (io_u->offset >= f->real_file_size)
 		return 1;
 
 	return 0;
 }
 
-static unsigned int get_next_buflen(struct thread_data *td, struct fio_file *f,
-				    struct io_u *io_u)
+static unsigned int get_next_buflen(struct thread_data *td, struct io_u *io_u)
 {
 	const int ddir = io_u->ddir;
 	unsigned int buflen;
 	long r;
 
-	if (td->min_bs[ddir] == td->max_bs[ddir])
-		buflen = td->min_bs[ddir];
+	if (td->o.min_bs[ddir] == td->o.max_bs[ddir])
+		buflen = td->o.min_bs[ddir];
 	else {
 		r = os_random_long(&td->bsrange_state);
-		buflen = (unsigned int) (1 + (double) (td->max_bs[ddir] - 1) * r / (RAND_MAX + 1.0));
-		if (!td->bs_unaligned)
-			buflen = (buflen + td->min_bs[ddir] - 1) & ~(td->min_bs[ddir] - 1);
+		if (!td->o.bssplit_nr)
+			buflen = (unsigned int) (1 + (double) (td->o.max_bs[ddir] - 1) * r / (RAND_MAX + 1.0));
+		else {
+			long perc = 0;
+			unsigned int i;
+
+			for (i = 0; i < td->o.bssplit_nr; i++) {
+				struct bssplit *bsp = &td->o.bssplit[i];
+
+				buflen = bsp->bs;
+				perc += bsp->perc;
+				if (r <= ((LONG_MAX / 100L) * perc))
+					break;
+			}
+		}
+		if (!td->o.bs_unaligned)
+			buflen = (buflen + td->o.min_bs[ddir] - 1) & ~(td->o.min_bs[ddir] - 1);
 	}
 
-	while (buflen + io_u->offset > f->real_file_size) {
-		if (buflen == td->min_bs[ddir])
-			return 0;
-
-		buflen = td->min_bs[ddir];
-	}
+	if (io_u->offset + buflen > io_u->file->real_file_size)
+		buflen = td->o.min_bs[ddir];
 
 	return buflen;
 }
 
+static void set_rwmix_bytes(struct thread_data *td)
+{
+	unsigned long long rbytes;
+	unsigned int diff;
+
+	/*
+	 * we do time or byte based switch. this is needed because
+	 * buffered writes may issue a lot quicker than they complete,
+	 * whereas reads do not.
+	 */
+	rbytes = td->io_bytes[td->rwmix_ddir] - td->rwmix_bytes;
+	diff = td->o.rwmix[td->rwmix_ddir ^ 1];
+
+	td->rwmix_bytes = td->io_bytes[td->rwmix_ddir] + (rbytes * ((100 - diff)) / diff);
+}
+
+static inline enum fio_ddir get_rand_ddir(struct thread_data *td)
+{
+	unsigned int v;
+	long r;
+
+	r = os_random_long(&td->rwmix_state);
+	v = 1 + (int) (100.0 * (r / (RAND_MAX + 1.0)));
+	if (v < td->o.rwmix[DDIR_READ])
+		return DDIR_READ;
+
+	return DDIR_WRITE;
+}
+
 /*
  * Return the data direction for the next io_u. If the job is a
  * mixed read/write workload, check the rwmix cycle and switch if
@@ -165,23 +250,45 @@ static enum fio_ddir get_rw_ddir(struct thread_data *td)
 	if (td_rw(td)) {
 		struct timeval now;
 		unsigned long elapsed;
+		unsigned int cycle;
 
 		fio_gettime(&now, NULL);
 	 	elapsed = mtime_since_now(&td->rwmix_switch);
 
+		/*
+		 * if this is the first cycle, make it shorter
+		 */
+		cycle = td->o.rwmixcycle;
+		if (!td->rwmix_bytes)
+			cycle /= 10;
+
 		/*
 		 * Check if it's time to seed a new data direction.
 		 */
-		if (elapsed >= td->rwmixcycle) {
-			unsigned int v;
-			long r;
-
-			r = os_random_long(&td->rwmix_state);
-			v = 1 + (int) (100.0 * (r / (RAND_MAX + 1.0)));
-			if (v < td->rwmixread)
-				td->rwmix_ddir = DDIR_READ;
-			else
-				td->rwmix_ddir = DDIR_WRITE;
+		if (elapsed >= cycle ||
+		    td->io_bytes[td->rwmix_ddir] >= td->rwmix_bytes) {
+			unsigned long long max_bytes;
+			enum fio_ddir ddir;			
+
+			/*
+			 * Put a top limit on how many bytes we do for
+			 * one data direction, to avoid overflowing the
+			 * ranges too much
+			 */
+			ddir = get_rand_ddir(td);
+			max_bytes = td->this_io_bytes[ddir];
+			if (max_bytes >= (td->o.size * td->o.rwmix[ddir] / 100)) {
+				if (!td->rw_end_set[ddir]) {
+					td->rw_end_set[ddir] = 1;
+					memcpy(&td->rw_end[ddir], &now, sizeof(now));
+				}
+				ddir ^= 1;
+			}
+
+			if (ddir != td->rwmix_ddir)
+				set_rwmix_bytes(td);
+
+			td->rwmix_ddir = ddir;
 			memcpy(&td->rwmix_switch, &now, sizeof(now));
 		}
 		return td->rwmix_ddir;
@@ -193,133 +300,369 @@ static enum fio_ddir get_rw_ddir(struct thread_data *td)
 
 void put_io_u(struct thread_data *td, struct io_u *io_u)
 {
+	assert((io_u->flags & IO_U_F_FREE) == 0);
+	io_u->flags |= IO_U_F_FREE;
+
+	if (io_u->file)
+		put_file(td, io_u->file);
+
 	io_u->file = NULL;
 	list_del(&io_u->list);
 	list_add(&io_u->list, &td->io_u_freelist);
 	td->cur_depth--;
 }
 
-static int fill_io_u(struct thread_data *td, struct fio_file *f,
-		     struct io_u *io_u)
+void requeue_io_u(struct thread_data *td, struct io_u **io_u)
 {
-	/*
-	 * If using an iolog, grab next piece if any available.
-	 */
-	if (td->read_iolog)
-		return read_iolog_get(td, io_u);
+	struct io_u *__io_u = *io_u;
+
+	__io_u->flags |= IO_U_F_FREE;
+	__io_u->flags &= ~IO_U_F_FLIGHT;
+
+	list_del(&__io_u->list);
+	list_add_tail(&__io_u->list, &td->io_u_requeues);
+	td->cur_depth--;
+	*io_u = NULL;
+}
+
+static int fill_io_u(struct thread_data *td, struct io_u *io_u)
+{
+	if (td->io_ops->flags & FIO_NOIO)
+		goto out;
 
 	/*
 	 * see if it's time to sync
 	 */
-	if (td->fsync_blocks && !(td->io_blocks[DDIR_WRITE] % td->fsync_blocks)
-	    && should_fsync(td)) {
+	if (td->o.fsync_blocks &&
+	   !(td->io_issues[DDIR_WRITE] % td->o.fsync_blocks) &&
+	     td->io_issues[DDIR_WRITE] && should_fsync(td)) {
 		io_u->ddir = DDIR_SYNC;
-		io_u->file = f;
-		return 0;
+		goto out;
 	}
 
 	io_u->ddir = get_rw_ddir(td);
 
+	/*
+	 * See if it's time to switch to a new zone
+	 */
+	if (td->zone_bytes >= td->o.zone_size) {
+		td->zone_bytes = 0;
+		io_u->file->last_pos += td->o.zone_skip;
+		td->io_skip_bytes += td->o.zone_skip;
+	}
+
 	/*
 	 * No log, let the seq/rand engine retrieve the next buflen and
 	 * position.
 	 */
-	if (get_next_offset(td, f, io_u))
+	if (get_next_offset(td, io_u))
 		return 1;
 
-	io_u->buflen = get_next_buflen(td, f, io_u);
+	io_u->buflen = get_next_buflen(td, io_u);
 	if (!io_u->buflen)
 		return 1;
 
+	if (io_u->offset + io_u->buflen > io_u->file->real_file_size)
+		return 1;
+
 	/*
 	 * mark entry before potentially trimming io_u
 	 */
-	if (!td->read_iolog && !td->sequential && !td->norandommap)
-		mark_random_map(td, f, io_u);
+	if (td_random(td) && !td->o.norandommap)
+		mark_random_map(td, io_u);
 
 	/*
 	 * If using a write iolog, store this entry.
 	 */
-	if (td->write_iolog_file)
-		write_iolog_put(td, io_u);
-
-	io_u->file = f;
+out:
+	log_io_u(td, io_u);
 	return 0;
 }
 
-static void io_u_mark_depth(struct thread_data *td)
+void io_u_mark_depth(struct thread_data *td, struct io_u *io_u)
 {
 	int index = 0;
 
+	if (io_u->ddir == DDIR_SYNC)
+		return;
+
 	switch (td->cur_depth) {
 	default:
-		index++;
+		index = 6;
+		break;
 	case 32 ... 63:
-		index++;
+		index = 5;
+		break;
 	case 16 ... 31:
-		index++;
+		index = 4;
+		break;
 	case 8 ... 15:
-		index++;
+		index = 3;
+		break;
 	case 4 ... 7:
-		index++;
+		index = 2;
+		break;
 	case 2 ... 3:
-		index++;
+		index = 1;
 	case 1:
 		break;
 	}
 
-	td->io_u_map[index]++;
-	td->total_io_u++;
+	td->ts.io_u_map[index]++;
+	td->ts.total_io_u[io_u->ddir]++;
+}
+
+static void io_u_mark_lat_usec(struct thread_data *td, unsigned long usec)
+{
+	int index = 0;
+
+	assert(usec < 1000);
+
+	switch (usec) {
+	case 750 ... 999:
+		index = 9;
+		break;
+	case 500 ... 749:
+		index = 8;
+		break;
+	case 250 ... 499:
+		index = 7;
+		break;
+	case 100 ... 249:
+		index = 6;
+		break;
+	case 50 ... 99:
+		index = 5;
+		break;
+	case 20 ... 49:
+		index = 4;
+		break;
+	case 10 ... 19:
+		index = 3;
+		break;
+	case 4 ... 9:
+		index = 2;
+		break;
+	case 2 ... 3:
+		index = 1;
+	case 0 ... 1:
+		break;
+	}
+
+	assert(index < FIO_IO_U_LAT_U_NR);
+	td->ts.io_u_lat_u[index]++;
 }
 
-static void io_u_mark_latency(struct thread_data *td, unsigned long msec)
+static void io_u_mark_lat_msec(struct thread_data *td, unsigned long msec)
 {
 	int index = 0;
 
 	switch (msec) {
 	default:
-		index++;
-	case 1024 ... 2047:
-		index++;
-	case 512 ... 1023:
-		index++;
-	case 256 ... 511:
-		index++;
-	case 128 ... 255:
-		index++;
-	case 64 ... 127:
-		index++;
-	case 32 ... 63:
-		index++;
-	case 16 ... 31:
-		index++;
-	case 8 ... 15:
-		index++;
-	case 4 ... 7:
-		index++;
+		index = 11;
+		break;
+	case 1000 ... 1999:
+		index = 10;
+		break;
+	case 750 ... 999:
+		index = 9;
+		break;
+	case 500 ... 749:
+		index = 8;
+		break;
+	case 250 ... 499:
+		index = 7;
+		break;
+	case 100 ... 249:
+		index = 6;
+		break;
+	case 50 ... 99:
+		index = 5;
+		break;
+	case 20 ... 49:
+		index = 4;
+		break;
+	case 10 ... 19:
+		index = 3;
+		break;
+	case 4 ... 9:
+		index = 2;
+		break;
 	case 2 ... 3:
-		index++;
+		index = 1;
 	case 0 ... 1:
 		break;
 	}
 
-	td->io_u_lat[index]++;
+	assert(index < FIO_IO_U_LAT_M_NR);
+	td->ts.io_u_lat_m[index]++;
+}
+
+static void io_u_mark_latency(struct thread_data *td, unsigned long usec)
+{
+	if (usec < 1000)
+		io_u_mark_lat_usec(td, usec);
+	else
+		io_u_mark_lat_msec(td, usec / 1000);
+}
+
+/*
+ * Get next file to service by choosing one at random
+ */
+static struct fio_file *get_next_file_rand(struct thread_data *td, int goodf,
+					   int badf)
+{
+	struct fio_file *f;
+	int fno;
+
+	do {
+		long r = os_random_long(&td->next_file_state);
+
+		fno = (unsigned int) ((double) td->o.nr_files * (r / (RAND_MAX + 1.0)));
+		f = &td->files[fno];
+		if (f->flags & FIO_FILE_DONE)
+			continue;
+
+		if ((!goodf || (f->flags & goodf)) && !(f->flags & badf))
+			return f;
+	} while (1);
+}
+
+/*
+ * Get next file to service by doing round robin between all available ones
+ */
+static struct fio_file *get_next_file_rr(struct thread_data *td, int goodf,
+					 int badf)
+{
+	unsigned int old_next_file = td->next_file;
+	struct fio_file *f;
+
+	do {
+		f = &td->files[td->next_file];
+
+		td->next_file++;
+		if (td->next_file >= td->o.nr_files)
+			td->next_file = 0;
+
+		if (f->flags & FIO_FILE_DONE) {
+			f = NULL;
+			continue;
+		}
+
+		if ((!goodf || (f->flags & goodf)) && !(f->flags & badf))
+			break;
+
+		f = NULL;
+	} while (td->next_file != old_next_file);
+
+	return f;
+}
+
+static struct fio_file *get_next_file(struct thread_data *td)
+{
+	struct fio_file *f;
+
+	assert(td->o.nr_files <= td->files_index);
+
+	if (!td->nr_open_files || td->nr_done_files >= td->o.nr_files)
+		return NULL;
+
+	f = td->file_service_file;
+	if (f && (f->flags & FIO_FILE_OPEN) && td->file_service_left--)
+		return f;
+
+	if (td->o.file_service_type == FIO_FSERVICE_RR)
+		f = get_next_file_rr(td, FIO_FILE_OPEN, FIO_FILE_CLOSING);
+	else
+		f = get_next_file_rand(td, FIO_FILE_OPEN, FIO_FILE_CLOSING);
+
+	td->file_service_file = f;
+	td->file_service_left = td->file_service_nr - 1;
+	return f;
+}
+
+static struct fio_file *find_next_new_file(struct thread_data *td)
+{
+	struct fio_file *f;
+
+	if (!td->nr_open_files || td->nr_done_files >= td->o.nr_files)
+		return NULL;
+
+	if (td->o.file_service_type == FIO_FSERVICE_RR)
+		f = get_next_file_rr(td, 0, FIO_FILE_OPEN);
+	else
+		f = get_next_file_rand(td, 0, FIO_FILE_OPEN);
+
+	return f;
+}
+
+static int set_io_u_file(struct thread_data *td, struct io_u *io_u)
+{
+	struct fio_file *f;
+
+	do {
+		f = get_next_file(td);
+		if (!f)
+			return 1;
+
+set_file:
+		io_u->file = f;
+		get_file(f);
+
+		if (!fill_io_u(td, io_u))
+			break;
+
+		/*
+		 * td_io_close() does a put_file() as well, so no need to
+		 * do that here.
+		 */
+		io_u->file = NULL;
+		td_io_close_file(td, f);
+		f->flags |= FIO_FILE_DONE;
+		td->nr_done_files++;
+
+		/*
+		 * probably not the right place to do this, but see
+		 * if we need to open a new file
+		 */
+		if (td->nr_open_files < td->o.open_files &&
+		    td->o.open_files != td->o.nr_files) {
+			f = find_next_new_file(td);
+
+			if (!f || td_io_open_file(td, f))
+				return 1;
+
+			goto set_file;
+		}
+	} while (1);
+
+	return 0;
 }
 
+
 struct io_u *__get_io_u(struct thread_data *td)
 {
 	struct io_u *io_u = NULL;
 
-	if (!queue_full(td)) {
+	if (!list_empty(&td->io_u_requeues))
+		io_u = list_entry(td->io_u_requeues.next, struct io_u, list);
+	else if (!queue_full(td)) {
 		io_u = list_entry(td->io_u_freelist.next, struct io_u, list);
 
 		io_u->buflen = 0;
-		io_u->error = 0;
 		io_u->resid = 0;
+		io_u->file = NULL;
+		io_u->end_io = NULL;
+	}
+
+	if (io_u) {
+		assert(io_u->flags & IO_U_F_FREE);
+		io_u->flags &= ~IO_U_F_FREE;
+
+		io_u->error = 0;
 		list_del(&io_u->list);
 		list_add(&io_u->list, &td->io_u_busylist);
 		td->cur_depth++;
-		io_u_mark_depth(td);
 	}
 
 	return io_u;
@@ -329,64 +672,84 @@ struct io_u *__get_io_u(struct thread_data *td)
  * Return an io_u to be processed. Gets a buflen and offset, sets direction,
  * etc. The returned io_u is fully ready to be prepped and submitted.
  */
-struct io_u *get_io_u(struct thread_data *td, struct fio_file *f)
+struct io_u *get_io_u(struct thread_data *td)
 {
+	struct fio_file *f;
 	struct io_u *io_u;
 
 	io_u = __get_io_u(td);
 	if (!io_u)
 		return NULL;
 
-	if (td->zone_bytes >= td->zone_size) {
-		td->zone_bytes = 0;
-		f->last_pos += td->zone_skip;
-	}
-
-	if (fill_io_u(td, f, io_u)) {
-		put_io_u(td, io_u);
-		return NULL;
-	}
-
-	if (io_u->buflen + io_u->offset > f->real_file_size) {
-		if (td->io_ops->flags & FIO_RAWIO) {
-			put_io_u(td, io_u);
-			return NULL;
-		}
+	/*
+	 * from a requeue, io_u already setup
+	 */
+	if (io_u->file)
+		goto out;
 
-		io_u->buflen = f->real_file_size - io_u->offset;
-	}
+	/*
+	 * If using an iolog, grab next piece if any available.
+	 */
+	if (td->o.read_iolog_file) {
+		if (read_iolog_get(td, io_u))
+			goto err_put;
+	} else if (set_io_u_file(td, io_u))
+		goto err_put;
+	
+	f = io_u->file;
+	assert(f->flags & FIO_FILE_OPEN);
 
 	if (io_u->ddir != DDIR_SYNC) {
-		if (!io_u->buflen) {
-			put_io_u(td, io_u);
-			return NULL;
-		}
+		if (!io_u->buflen)
+			goto err_put;
 
 		f->last_pos = io_u->offset + io_u->buflen;
 
-		if (td->verify != VERIFY_NONE)
+		if (td->o.verify != VERIFY_NONE)
 			populate_verify_io_u(td, io_u);
 	}
 
 	/*
 	 * Set io data pointers.
 	 */
+	io_u->endpos = io_u->offset + io_u->buflen;
+out:
 	io_u->xfer_buf = io_u->buf;
 	io_u->xfer_buflen = io_u->buflen;
 
-	if (td_io_prep(td, io_u)) {
-		put_io_u(td, io_u);
-		return NULL;
+	if (!td_io_prep(td, io_u)) {
+		fio_gettime(&io_u->start_time, NULL);
+		return io_u;
 	}
+err_put:
+	put_io_u(td, io_u);
+	return NULL;
+}
 
-	fio_gettime(&io_u->start_time, NULL);
-	return io_u;
+void io_u_log_error(struct thread_data *td, struct io_u *io_u)
+{
+	const char *msg[] = { "read", "write", "sync" };
+
+	log_err("fio: io_u error");
+
+	if (io_u->file)
+		log_err(" on file %s", io_u->file->file_name);
+
+	log_err(": %s\n", strerror(io_u->error));
+
+	log_err("     %s offset=%llu, buflen=%lu\n", msg[io_u->ddir], io_u->offset, io_u->xfer_buflen);
+
+	if (!td->error)
+		td_verror(td, io_u->error, "io_u error");
 }
 
 static void io_completed(struct thread_data *td, struct io_u *io_u,
 			 struct io_completion_data *icd)
 {
-	unsigned long msec;
+	unsigned long usec;
+
+	assert(io_u->flags & IO_U_F_FLIGHT);
+	io_u->flags &= ~IO_U_F_FLIGHT;
 
 	if (io_u->ddir == DDIR_SYNC) {
 		td->last_was_sync = 1;
@@ -405,34 +768,36 @@ static void io_completed(struct thread_data *td, struct io_u *io_u,
 		td->zone_bytes += bytes;
 		td->this_io_bytes[idx] += bytes;
 
-		io_u->file->last_completed_pos = io_u->offset + io_u->buflen;
+		io_u->file->last_completed_pos = io_u->endpos;
 
-		msec = mtime_since(&io_u->issue_time, &icd->time);
+		usec = utime_since(&io_u->issue_time, &icd->time);
 
-		add_clat_sample(td, idx, msec);
+		add_clat_sample(td, idx, usec);
 		add_bw_sample(td, idx, &icd->time);
-		io_u_mark_latency(td, msec);
+		io_u_mark_latency(td, usec);
 
-		if ((td_rw(td) || td_write(td)) && idx == DDIR_WRITE)
+		if (td_write(td) && idx == DDIR_WRITE &&
+		    td->o.do_verify &&
+		    td->o.verify != VERIFY_NONE)
 			log_io_piece(td, io_u);
 
 		icd->bytes_done[idx] += bytes;
 
-		if (icd->handler) {
-			ret = icd->handler(io_u);
+		if (io_u->end_io) {
+			ret = io_u->end_io(td, io_u);
 			if (ret && !icd->error)
 				icd->error = ret;
 		}
-	} else
+	} else {
 		icd->error = io_u->error;
+		io_u_log_error(td, io_u);
+	}
 }
 
-static void init_icd(struct io_completion_data *icd, endio_handler *handler,
-		     int nr)
+static void init_icd(struct io_completion_data *icd, int nr)
 {
 	fio_gettime(&icd->time, NULL);
 
-	icd->handler = handler;
 	icd->nr = nr;
 
 	icd->error = 0;
@@ -453,44 +818,140 @@ static void ios_completed(struct thread_data *td,
 	}
 }
 
-long io_u_sync_complete(struct thread_data *td, struct io_u *io_u,
-			endio_handler *handler)
+/*
+ * Complete a single io_u for the sync engines.
+ */
+long io_u_sync_complete(struct thread_data *td, struct io_u *io_u)
 {
 	struct io_completion_data icd;
 
-	init_icd(&icd, handler, 1);
+	init_icd(&icd, 1);
 	io_completed(td, io_u, &icd);
 	put_io_u(td, io_u);
 
 	if (!icd.error)
 		return icd.bytes_done[0] + icd.bytes_done[1];
 
+	td_verror(td, icd.error, "io_u_sync_complete");
 	return -1;
 }
 
-long io_u_queued_complete(struct thread_data *td, int min_events,
-			  endio_handler *handler)
-
+/*
+ * Called to complete min_events number of io for the async engines.
+ */
+long io_u_queued_complete(struct thread_data *td, int min_events)
 {
-	struct timespec ts = { .tv_sec = 0, .tv_nsec = 0, };
-	struct timespec *tsp = NULL;
 	struct io_completion_data icd;
+	struct timespec *tvp = NULL;
 	int ret;
+	struct timespec ts = { .tv_sec = 0, .tv_nsec = 0, };
 
-	if (min_events > 0)
-		tsp = &ts;
+	if (!min_events)
+		tvp = &ts;
 
-	ret = td_io_getevents(td, min_events, td->cur_depth, tsp);
+	ret = td_io_getevents(td, min_events, td->cur_depth, tvp);
 	if (ret < 0) {
-		td_verror(td, -ret);
+		td_verror(td, -ret, "td_io_getevents");
 		return ret;
 	} else if (!ret)
 		return ret;
 
-	init_icd(&icd, handler, ret);
+	init_icd(&icd, ret);
 	ios_completed(td, &icd);
 	if (!icd.error)
 		return icd.bytes_done[0] + icd.bytes_done[1];
 
+	td_verror(td, icd.error, "io_u_queued_complete");
 	return -1;
 }
+
+/*
+ * Call when io_u is really queued, to update the submission latency.
+ */
+void io_u_queued(struct thread_data *td, struct io_u *io_u)
+{
+	unsigned long slat_time;
+
+	slat_time = utime_since(&io_u->start_time, &io_u->issue_time);
+	add_slat_sample(td, io_u->ddir, slat_time);
+}
+
+#ifdef FIO_USE_TIMEOUT
+void io_u_set_timeout(struct thread_data *td)
+{
+	assert(td->cur_depth);
+
+	td->timer.it_interval.tv_sec = 0;
+	td->timer.it_interval.tv_usec = 0;
+	td->timer.it_value.tv_sec = IO_U_TIMEOUT + IO_U_TIMEOUT_INC;
+	td->timer.it_value.tv_usec = 0;
+	setitimer(ITIMER_REAL, &td->timer, NULL);
+	fio_gettime(&td->timeout_end, NULL);
+}
+
+static void io_u_dump(struct io_u *io_u)
+{
+	unsigned long t_start = mtime_since_now(&io_u->start_time);
+	unsigned long t_issue = mtime_since_now(&io_u->issue_time);
+
+	log_err("io_u=%p, t_start=%lu, t_issue=%lu\n", io_u, t_start, t_issue);
+	log_err("  buf=%p/%p, len=%lu/%lu, offset=%llu\n", io_u->buf, io_u->xfer_buf, io_u->buflen, io_u->xfer_buflen, io_u->offset);
+	log_err("  ddir=%d, fname=%s\n", io_u->ddir, io_u->file->file_name);
+}
+#else
+void io_u_set_timeout(struct thread_data fio_unused *td)
+{
+}
+#endif
+
+#ifdef FIO_USE_TIMEOUT
+static void io_u_timeout_handler(int fio_unused sig)
+{
+	struct thread_data *td, *__td;
+	pid_t pid = getpid();
+	struct list_head *entry;
+	struct io_u *io_u;
+	int i;
+
+	log_err("fio: io_u timeout\n");
+
+	/*
+	 * TLS would be nice...
+	 */
+	td = NULL;
+	for_each_td(__td, i) {
+		if (__td->pid == pid) {
+			td = __td;
+			break;
+		}
+	}
+
+	if (!td) {
+		log_err("fio: io_u timeout, can't find job\n");
+		exit(1);
+	}
+
+	if (!td->cur_depth) {
+		log_err("fio: timeout without pending work?\n");
+		return;
+	}
+
+	log_err("fio: io_u timeout: job=%s, pid=%d\n", td->o.name, td->pid);
+
+	list_for_each(entry, &td->io_u_busylist) {
+		io_u = list_entry(entry, struct io_u, list);
+
+		io_u_dump(io_u);
+	}
+
+	td_verror(td, ETIMEDOUT, "io_u timeout");
+	exit(1);
+}
+#endif
+
+void io_u_init_timeout(void)
+{
+#ifdef FIO_USE_TIMEOUT
+	signal(SIGALRM, io_u_timeout_handler);
+#endif
+}