/*
* libaio engine
*
* IO engine using the Linux native aio interface.
*
*/
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <libaio.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "../fio.h"
#include "../lib/pow2.h"
#include "../optgroup.h"
#include "../lib/memalign.h"
/* Should be defined in newest aio_abi.h */
#ifndef IOCB_FLAG_IOPRIO
#define IOCB_FLAG_IOPRIO (1 << 1)
#endif
static int fio_libaio_commit(struct thread_data *td);
static int fio_libaio_init(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;
struct io_u **io_u_index;
/*
* 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;
unsigned int cmdprio_percentage;
};
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,
},
#ifdef FIO_HAVE_IOPRIO_CLASS
{
.name = "cmdprio_percentage",
.lname = "high priority percentage",
.type = FIO_OPT_INT,
.off1 = offsetof(struct libaio_options, cmdprio_percentage),
.minval = 1,
.maxval = 100,
.help = "Send high priority I/O this percentage of the time",
.category = FIO_OPT_C_ENGINE,
.group = FIO_OPT_G_LIBAIO,
},
#else
{
.name = "cmdprio_percentage",
.lname = "high priority percentage",
.type = FIO_OPT_UNSUPPORTED,
.help = "Your platform does not support I/O priority classes",
},
#endif
{
.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;
struct iocb *iocb = &io_u->iocb;
if (io_u->ddir == DDIR_READ) {
io_prep_pread(iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
} else if (io_u->ddir == DDIR_WRITE) {
io_prep_pwrite(iocb, f->fd, io_u->xfer_buf, io_u->xfer_buflen, io_u->offset);
} else if (ddir_sync(io_u->ddir))
io_prep_fsync(iocb, f->fd);
return 0;
}
static void fio_libaio_prio_prep(struct thread_data *td, struct io_u *io_u)
{
struct libaio_options *o = td->eo;
if (rand_between(&td->prio_state, 0, 99) < o->cmdprio_percentage) {
io_u->iocb.aio_reqprio = IOPRIO_CLASS_RT << IOPRIO_CLASS_SHIFT;
io_u->iocb.u.c.flags |= IOCB_FLAG_IOPRIO;
io_u->flags |= IO_U_F_PRIORITY;
}
return;
}
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_min == 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);
if (actual_min)
usleep(10);
} else if (r != -EINTR)
break;
} while (events < min);
return r < 0 ? r : events;
}
static enum fio_q_status fio_libaio_queue(struct thread_data *td,
struct io_u *io_u)
{
struct libaio_data *ld = td->io_ops_data;
struct libaio_options *o = td->eo;
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);
io_u_mark_submit(td, 1);
io_u_mark_complete(td, 1);
return FIO_Q_COMPLETED;
}
if (o->cmdprio_percentage)
fio_libaio_prio_prep(td, io_u);
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 timespec 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 timespec ts;
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(&ts, NULL);
wait_start = 1;
} else if (mtime_since_now(&ts) > 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_post_init(struct thread_data *td)
{
struct libaio_data *ld = td->io_ops_data;
int err;
err = io_queue_init(td->o.iodepth, &ld->aio_ctx);
if (err) {
td_verror(td, -err, "io_queue_init");
return 1;
}
return 0;
}
static int fio_libaio_init(struct thread_data *td)
{
struct libaio_data *ld;
struct thread_options *to = &td->o;
struct libaio_options *o = td->eo;
ld = calloc(1, sizeof(*ld));
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;
/*
* Check for option conflicts
*/
if ((fio_option_is_set(to, ioprio) || fio_option_is_set(to, ioprio_class)) &&
o->cmdprio_percentage != 0) {
log_err("%s: cmdprio_percentage option and mutually exclusive "
"prio or prioclass option is set, exiting\n", to->name);
td_verror(td, EINVAL, "fio_libaio_init");
return 1;
}
return 0;
}
static struct ioengine_ops ioengine = {
.name = "libaio",
.version = FIO_IOOPS_VERSION,
.flags = FIO_ASYNCIO_SYNC_TRIM,
.init = fio_libaio_init,
.post_init = fio_libaio_post_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);
}