blob: 15e4c2578fe9ee978af4f4a1847ecf571871718e [file] [log] [blame]
/*
* syslet engine
*
* IO engine that does regular pread(2)/pwrite(2) to transfer data, but
* with syslets to make the execution async.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <malloc.h>
#include <asm/unistd.h>
#include "../fio.h"
#include "../lib/fls.h"
#ifdef FIO_HAVE_SYSLET
#ifdef __NR_pread64
#define __NR_fio_pread __NR_pread64
#define __NR_fio_pwrite __NR_pwrite64
#else
#define __NR_fio_pread __NR_pread
#define __NR_fio_pwrite __NR_pwrite
#endif
struct syslet_data {
struct io_u **events;
unsigned int nr_events;
struct syslet_ring *ring;
unsigned int ring_mask;
void *stack;
};
static void fio_syslet_add_event(struct thread_data *td, struct io_u *io_u)
{
struct syslet_data *sd = td->io_ops->data;
assert(sd->nr_events < td->o.iodepth);
sd->events[sd->nr_events++] = io_u;
}
static void fio_syslet_add_events(struct thread_data *td, unsigned int nr)
{
struct syslet_data *sd = td->io_ops->data;
unsigned int i, uidx;
uidx = sd->ring->user_tail;
read_barrier();
for (i = 0; i < nr; i++) {
unsigned int idx = (i + uidx) & sd->ring_mask;
struct syslet_completion *comp = &sd->ring->comp[idx];
struct io_u *io_u = (struct io_u *) (long) comp->caller_data;
long ret;
ret = comp->status;
if (ret <= 0) {
io_u->resid = io_u->xfer_buflen;
io_u->error = -ret;
} else {
io_u->resid = io_u->xfer_buflen - ret;
io_u->error = 0;
}
fio_syslet_add_event(td, io_u);
}
}
static void fio_syslet_wait_for_events(struct thread_data *td)
{
struct syslet_data *sd = td->io_ops->data;
struct syslet_ring *ring = sd->ring;
do {
unsigned int kh = ring->kernel_head;
int ret;
/*
* first reap events that are already completed
*/
if (ring->user_tail != kh) {
unsigned int nr = kh - ring->user_tail;
fio_syslet_add_events(td, nr);
ring->user_tail = kh;
break;
}
/*
* block waiting for at least one event
*/
ret = syscall(__NR_syslet_ring_wait, ring, ring->user_tail);
assert(!ret);
} while (1);
}
static int fio_syslet_getevents(struct thread_data *td, unsigned int min,
unsigned int fio_unused max,
struct timespec fio_unused *t)
{
struct syslet_data *sd = td->io_ops->data;
long ret;
/*
* While we have less events than requested, block waiting for them
* (if we have to, there may already be more completed events ready
* for us - see fio_syslet_wait_for_events()
*/
while (sd->nr_events < min)
fio_syslet_wait_for_events(td);
ret = sd->nr_events;
sd->nr_events = 0;
return ret;
}
static struct io_u *fio_syslet_event(struct thread_data *td, int event)
{
struct syslet_data *sd = td->io_ops->data;
return sd->events[event];
}
static void fio_syslet_prep_sync(struct fio_file *f,
struct indirect_registers *regs)
{
FILL_IN(*regs, __NR_fsync, (long) f->fd);
}
static void fio_syslet_prep_datasync(struct fio_file *f,
struct indirect_registers *regs)
{
FILL_IN(*regs, __NR_fdatasync, (long) f->fd);
}
static void fio_syslet_prep_rw(struct io_u *io_u, struct fio_file *f,
struct indirect_registers *regs)
{
long nr;
/*
* prepare rw
*/
if (io_u->ddir == DDIR_READ)
nr = __NR_fio_pread;
else
nr = __NR_fio_pwrite;
FILL_IN(*regs, nr, (long) f->fd, (long) io_u->xfer_buf,
(long) io_u->xfer_buflen, (long) io_u->offset);
}
static void fio_syslet_prep(struct io_u *io_u, struct indirect_registers *regs)
{
struct fio_file *f = io_u->file;
if (io_u->ddir == DDIR_SYNC)
fio_syslet_prep_sync(f, regs);
else if (io_u->ddir == DDIR_DATASYNC)
fio_syslet_prep_datasync(f, regs);
else
fio_syslet_prep_rw(io_u, f, regs);
}
static void ret_func(void)
{
syscall(__NR_exit);
}
static int fio_syslet_queue(struct thread_data *td, struct io_u *io_u)
{
struct syslet_data *sd = td->io_ops->data;
union indirect_params params;
struct indirect_registers regs;
int ret;
fio_ro_check(td, io_u);
memset(&params, 0, sizeof(params));
fill_syslet_args(&params.syslet, sd->ring, (long)io_u, ret_func, sd->stack);
fio_syslet_prep(io_u, &regs);
ret = syscall(__NR_indirect, &regs, &params, sizeof(params), 0);
if (ret == (int) io_u->xfer_buflen) {
/*
* completed sync, account. this also catches fsync().
*/
return FIO_Q_COMPLETED;
} else if (ret < 0) {
/*
* queued for async execution
*/
if (errno == ESYSLETPENDING)
return FIO_Q_QUEUED;
}
io_u->error = errno;
td_verror(td, io_u->error, "xfer");
return FIO_Q_COMPLETED;
}
static int check_syslet_support(struct syslet_data *sd)
{
union indirect_params params;
struct indirect_registers regs;
pid_t pid, my_pid = getpid();
memset(&params, 0, sizeof(params));
fill_syslet_args(&params.syslet, sd->ring, 0, ret_func, sd->stack);
FILL_IN(regs, __NR_getpid);
pid = syscall(__NR_indirect, &regs, &params, sizeof(params), 0);
if (pid == my_pid)
return 0;
return 1;
}
static void fio_syslet_cleanup(struct thread_data *td)
{
struct syslet_data *sd = td->io_ops->data;
if (sd) {
free(sd->events);
free(sd->ring);
free(sd);
}
}
static int fio_syslet_init(struct thread_data *td)
{
struct syslet_data *sd;
void *ring = NULL, *stack = NULL;
unsigned int ring_size, ring_nr;
sd = malloc(sizeof(*sd));
memset(sd, 0, sizeof(*sd));
sd->events = malloc(sizeof(struct io_u *) * td->o.iodepth);
memset(sd->events, 0, sizeof(struct io_u *) * td->o.iodepth);
/*
* The ring needs to be a power-of-2, so round it up if we have to
*/
ring_nr = td->o.iodepth;
if (ring_nr & (ring_nr - 1))
ring_nr = 1 << __fls(ring_nr);
ring_size = sizeof(struct syslet_ring) +
ring_nr * sizeof(struct syslet_completion);
if (posix_memalign(&ring, sizeof(uint64_t), ring_size))
goto err_mem;
if (posix_memalign(&stack, page_size, page_size))
goto err_mem;
sd->ring = ring;
sd->ring_mask = ring_nr - 1;
sd->stack = stack;
memset(sd->ring, 0, ring_size);
sd->ring->elements = ring_nr;
if (!check_syslet_support(sd)) {
td->io_ops->data = sd;
return 0;
}
log_err("fio: syslets do not appear to work\n");
err_mem:
free(sd->events);
if (ring)
free(ring);
if (stack)
free(stack);
free(sd);
return 1;
}
static struct ioengine_ops ioengine = {
.name = "syslet-rw",
.version = FIO_IOOPS_VERSION,
.init = fio_syslet_init,
.queue = fio_syslet_queue,
.getevents = fio_syslet_getevents,
.event = fio_syslet_event,
.cleanup = fio_syslet_cleanup,
.open_file = generic_open_file,
.close_file = generic_close_file,
.get_file_size = generic_get_file_size,
};
#else /* FIO_HAVE_SYSLET */
/*
* 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_syslet_init(struct thread_data fio_unused *td)
{
log_err("fio: syslet not available\n");
return 1;
}
static struct ioengine_ops ioengine = {
.name = "syslet-rw",
.version = FIO_IOOPS_VERSION,
.init = fio_syslet_init,
};
#endif /* FIO_HAVE_SYSLET */
static void fio_init fio_syslet_register(void)
{
register_ioengine(&ioengine);
}
static void fio_exit fio_syslet_unregister(void)
{
unregister_ioengine(&ioengine);
}