4 * IO engine that does regular pread(2)/pwrite(2) to transfer data, but
5 * with syslets to make the execution async.
14 #include <asm/unistd.h>
17 #include "../indirect.h"
18 #include "../syslet.h"
20 #ifdef FIO_HAVE_SYSLET
23 #define __NR_fio_pread __NR_pread64
24 #define __NR_fio_pwrite __NR_pwrite64
26 #define __NR_fio_pread __NR_pread
27 #define __NR_fio_pwrite __NR_pwrite
32 unsigned int nr_events;
34 struct syslet_ring *ring;
35 unsigned int ring_mask;
39 static void fio_syslet_add_event(struct thread_data *td, struct io_u *io_u)
41 struct syslet_data *sd = td->io_ops->data;
43 assert(sd->nr_events < td->o.iodepth);
44 sd->events[sd->nr_events++] = io_u;
47 static void fio_syslet_add_events(struct thread_data *td, unsigned int nr)
49 struct syslet_data *sd = td->io_ops->data;
52 uidx = sd->ring->user_tail;
55 for (i = 0; i < nr; i++) {
56 unsigned int idx = (i + uidx) & sd->ring_mask;
57 struct syslet_completion *comp = &sd->ring->comp[idx];
58 struct io_u *io_u = (struct io_u *) (long) comp->caller_data;
63 io_u->resid = io_u->xfer_buflen;
66 io_u->resid = io_u->xfer_buflen - ret;
70 fio_syslet_add_event(td, io_u);
74 static void fio_syslet_wait_for_events(struct thread_data *td)
76 struct syslet_data *sd = td->io_ops->data;
77 struct syslet_ring *ring = sd->ring;
80 unsigned int kh = ring->kernel_head;
84 * first reap events that are already completed
86 if (ring->user_tail != kh) {
87 unsigned int nr = kh - ring->user_tail;
89 fio_syslet_add_events(td, nr);
95 * block waiting for at least one event
97 ret = syscall(__NR_syslet_ring_wait, ring, ring->user_tail);
102 static int fio_syslet_getevents(struct thread_data *td, unsigned int min,
103 unsigned int fio_unused max,
104 struct timespec fio_unused *t)
106 struct syslet_data *sd = td->io_ops->data;
110 * While we have less events than requested, block waiting for them
112 while (sd->nr_events < (unsigned int) min)
113 fio_syslet_wait_for_events(td);
120 static struct io_u *fio_syslet_event(struct thread_data *td, int event)
122 struct syslet_data *sd = td->io_ops->data;
124 return sd->events[event];
127 static void fio_syslet_prep_sync(struct fio_file *f,
128 struct indirect_registers *regs)
130 FILL_IN(*regs, __NR_fsync, (long) f->fd);
133 static void fio_syslet_prep_rw(struct io_u *io_u, struct fio_file *f,
134 struct indirect_registers *regs)
141 if (io_u->ddir == DDIR_READ)
144 nr = __NR_fio_pwrite;
146 FILL_IN(*regs, nr, (long) f->fd, (long) io_u->xfer_buf,
147 (long) io_u->xfer_buflen, (long) io_u->offset);
150 static void fio_syslet_prep(struct io_u *io_u, struct indirect_registers *regs)
152 struct fio_file *f = io_u->file;
154 if (io_u->ddir == DDIR_SYNC)
155 fio_syslet_prep_sync(f, regs);
157 fio_syslet_prep_rw(io_u, f, regs);
160 static void ret_func(void)
165 static int fio_syslet_queue(struct thread_data *td, struct io_u *io_u)
167 struct syslet_data *sd = td->io_ops->data;
168 union indirect_params params;
169 struct indirect_registers regs;
172 fio_ro_check(td, io_u);
174 memset(¶ms, 0, sizeof(params));
175 fill_syslet_args(¶ms.syslet, sd->ring, (long)io_u, ret_func, sd->stack);
177 fio_syslet_prep(io_u, ®s);
179 ret = syscall(__NR_indirect, ®s, ¶ms, sizeof(params), 0);
180 if (ret == (int) io_u->xfer_buflen) {
182 * completed sync, account. this also catches fsync().
184 return FIO_Q_COMPLETED;
185 } else if (ret < 0) {
187 * queued for async execution
189 if (errno == ESYSLETPENDING)
194 td_verror(td, io_u->error, "xfer");
195 return FIO_Q_COMPLETED;
198 static int check_syslet_support(struct syslet_data *sd)
200 union indirect_params params;
201 struct indirect_registers regs;
202 pid_t pid, my_pid = getpid();
204 memset(¶ms, 0, sizeof(params));
205 fill_syslet_args(¶ms.syslet, sd->ring, 0, ret_func, sd->stack);
207 FILL_IN(regs, __NR_getpid);
209 pid = syscall(__NR_indirect, ®s, ¶ms, sizeof(params), 0);
216 static void fio_syslet_cleanup(struct thread_data *td)
218 struct syslet_data *sd = td->io_ops->data;
225 td->io_ops->data = NULL;
229 static int fio_syslet_init(struct thread_data *td)
231 struct syslet_data *sd;
232 void *ring = NULL, *stack = NULL;
233 unsigned int ring_size, ring_nr;
235 sd = malloc(sizeof(*sd));
236 memset(sd, 0, sizeof(*sd));
238 sd->events = malloc(sizeof(struct io_u *) * td->o.iodepth);
239 memset(sd->events, 0, sizeof(struct io_u *) * td->o.iodepth);
242 * The ring needs to be a power-of-2, so round it up if we have to
244 ring_nr = td->o.iodepth;
245 if (ring_nr & (ring_nr - 1)) {
248 while (ring_nr >>= 1)
254 ring_size = sizeof(struct syslet_ring) +
255 ring_nr * sizeof(struct syslet_completion);
256 if (posix_memalign(&ring, sizeof(uint64_t), ring_size))
258 if (posix_memalign(&stack, page_size, page_size))
262 sd->ring_mask = ring_nr - 1;
265 memset(sd->ring, 0, ring_size);
266 sd->ring->elements = ring_nr;
268 if (!check_syslet_support(sd)) {
269 td->io_ops->data = sd;
273 log_err("fio: syslets do not appear to work\n");
284 static struct ioengine_ops ioengine = {
286 .version = FIO_IOOPS_VERSION,
287 .init = fio_syslet_init,
288 .queue = fio_syslet_queue,
289 .getevents = fio_syslet_getevents,
290 .event = fio_syslet_event,
291 .cleanup = fio_syslet_cleanup,
292 .open_file = generic_open_file,
293 .close_file = generic_close_file,
296 #else /* FIO_HAVE_SYSLET */
299 * When we have a proper configure system in place, we simply wont build
300 * and install this io engine. For now install a crippled version that
301 * just complains and fails to load.
303 static int fio_syslet_init(struct thread_data fio_unused *td)
305 fprintf(stderr, "fio: syslet not available\n");
309 static struct ioengine_ops ioengine = {
311 .version = FIO_IOOPS_VERSION,
312 .init = fio_syslet_init,
315 #endif /* FIO_HAVE_SYSLET */
317 static void fio_init fio_syslet_register(void)
319 register_ioengine(&ioengine);
322 static void fio_exit fio_syslet_unregister(void)
324 unregister_ioengine(&ioengine);