sg engine: fix old comment
[fio.git] / engines / syslet-rw.c
CommitLineData
a4f4fdd7 1/*
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2 * syslet engine
3 *
4 * IO engine that does regular pread(2)/pwrite(2) to transfer data, but
5 * with syslets to make the execution async.
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6 *
7 */
8#include <stdio.h>
9#include <stdlib.h>
10#include <unistd.h>
11#include <errno.h>
12#include <assert.h>
b8846354 13#include <asm/unistd.h>
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14
15#include "../fio.h"
16#include "../os.h"
17
18#ifdef FIO_HAVE_SYSLET
19
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20#ifdef __NR_pread64
21#define __NR_fio_pread __NR_pread64
22#define __NR_fio_pwrite __NR_pwrite64
23#else
24#define __NR_fio_pread __NR_pread
25#define __NR_fio_pwrite __NR_pwrite
26#endif
27
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28struct syslet_data {
29 struct io_u **events;
30 unsigned int nr_events;
31
bf0dc8fa 32 struct async_head_user ahu;
a4f4fdd7 33 struct syslet_uatom **ring;
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34
35 struct syslet_uatom *head, *tail;
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36};
37
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38static void fio_syslet_complete_atom(struct thread_data *td,
39 struct syslet_uatom *atom)
40{
41 struct syslet_data *sd = td->io_ops->data;
5b38ee84 42 struct syslet_uatom *last;
9ff9de69 43 struct io_u *io_u;
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44
45 /*
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46 * complete from the beginning of the sequence up to (and
47 * including) this atom
9ff9de69 48 */
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49 last = atom;
50 io_u = atom->private;
51 atom = io_u->req.head;
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52
53 /*
54 * now complete in right order
55 */
5b38ee84 56 do {
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57 long ret;
58
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59 io_u = atom->private;
60 ret = *atom->ret_ptr;
e2e67912 61 if (ret >= 0)
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62 io_u->resid = io_u->xfer_buflen - ret;
63 else if (ret < 0)
64 io_u->error = ret;
65
2dc1bbeb 66 assert(sd->nr_events < td->o.iodepth);
9ff9de69 67 sd->events[sd->nr_events++] = io_u;
9ff9de69 68
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69 if (atom == last)
70 break;
9ff9de69 71
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72 atom = atom->next;
73 } while (1);
74
75 assert(!last->next);
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76}
77
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78/*
79 * Inspect the ring to see if we have completed events
80 */
81static void fio_syslet_complete(struct thread_data *td)
82{
83 struct syslet_data *sd = td->io_ops->data;
84
85 do {
86 struct syslet_uatom *atom;
a4f4fdd7 87
bf0dc8fa 88 atom = sd->ring[sd->ahu.user_ring_idx];
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89 if (!atom)
90 break;
91
bf0dc8fa 92 sd->ring[sd->ahu.user_ring_idx] = NULL;
2dc1bbeb 93 if (++sd->ahu.user_ring_idx == td->o.iodepth)
bf0dc8fa 94 sd->ahu.user_ring_idx = 0;
a4f4fdd7 95
9ff9de69 96 fio_syslet_complete_atom(td, atom);
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97 } while (1);
98}
99
100static int fio_syslet_getevents(struct thread_data *td, int min,
101 int fio_unused max,
102 struct timespec fio_unused *t)
103{
104 struct syslet_data *sd = td->io_ops->data;
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105 long ret;
106
107 do {
108 fio_syslet_complete(td);
109
110 /*
111 * do we have enough immediate completions?
112 */
113 if (sd->nr_events >= (unsigned int) min)
114 break;
115
116 /*
117 * OK, we need to wait for some events...
118 */
9ff9de69 119 ret = async_wait(1, sd->ahu.user_ring_idx, &sd->ahu);
a4f4fdd7 120 if (ret < 0)
e49499f8 121 return -errno;
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122 } while (1);
123
124 ret = sd->nr_events;
125 sd->nr_events = 0;
126 return ret;
127}
128
129static struct io_u *fio_syslet_event(struct thread_data *td, int event)
130{
131 struct syslet_data *sd = td->io_ops->data;
132
133 return sd->events[event];
134}
135
136static void init_atom(struct syslet_uatom *atom, int nr, void *arg0,
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137 void *arg1, void *arg2, void *arg3, void *ret_ptr,
138 unsigned long flags, void *priv)
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139{
140 atom->flags = flags;
141 atom->nr = nr;
142 atom->ret_ptr = ret_ptr;
a2e1b08a 143 atom->next = NULL;
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144 atom->arg_ptr[0] = arg0;
145 atom->arg_ptr[1] = arg1;
146 atom->arg_ptr[2] = arg2;
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147 atom->arg_ptr[3] = arg3;
148 atom->arg_ptr[4] = atom->arg_ptr[5] = NULL;
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149 atom->private = priv;
150}
151
152/*
153 * Use seek atom for sync
154 */
155static void fio_syslet_prep_sync(struct io_u *io_u, struct fio_file *f)
156{
a2e1b08a 157 init_atom(&io_u->req.atom, __NR_fsync, &f->fd, NULL, NULL, NULL,
7d44a745 158 &io_u->req.ret, 0, io_u);
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159}
160
161static void fio_syslet_prep_rw(struct io_u *io_u, struct fio_file *f)
162{
163 int nr;
164
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165 /*
166 * prepare rw
167 */
168 if (io_u->ddir == DDIR_READ)
1760e679 169 nr = __NR_fio_pread;
a4f4fdd7 170 else
1760e679 171 nr = __NR_fio_pwrite;
a4f4fdd7 172
a2e1b08a 173 init_atom(&io_u->req.atom, nr, &f->fd, &io_u->xfer_buf,
7d44a745 174 &io_u->xfer_buflen, &io_u->offset, &io_u->req.ret, 0, io_u);
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175}
176
177static int fio_syslet_prep(struct thread_data fio_unused *td, struct io_u *io_u)
178{
179 struct fio_file *f = io_u->file;
180
181 if (io_u->ddir == DDIR_SYNC)
182 fio_syslet_prep_sync(io_u, f);
183 else
184 fio_syslet_prep_rw(io_u, f);
185
186 return 0;
187}
188
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189static void cachemiss_thread_start(void)
190{
191 while (1)
7756b0d0 192 async_thread(NULL, NULL);
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193}
194
195#define THREAD_STACK_SIZE (16384)
196
197static unsigned long thread_stack_alloc()
198{
5b38ee84 199 return (unsigned long) malloc(THREAD_STACK_SIZE) + THREAD_STACK_SIZE;
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200}
201
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202static void fio_syslet_queued(struct thread_data *td, struct syslet_data *sd)
203{
204 struct syslet_uatom *atom;
205 struct timeval now;
206
207 fio_gettime(&now, NULL);
208
209 atom = sd->head;
210 while (atom) {
211 struct io_u *io_u = atom->private;
212
213 memcpy(&io_u->issue_time, &now, sizeof(now));
214 io_u_queued(td, io_u);
215 atom = atom->next;
216 }
217}
218
9ff9de69 219static int fio_syslet_commit(struct thread_data *td)
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220{
221 struct syslet_data *sd = td->io_ops->data;
bf0dc8fa 222 struct syslet_uatom *done;
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223
224 if (!sd->head)
225 return 0;
a4f4fdd7 226
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227 assert(!sd->tail->next);
228
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229 if (!sd->ahu.new_thread_stack)
230 sd->ahu.new_thread_stack = thread_stack_alloc();
231
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232 fio_syslet_queued(td, sd);
233
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234 /*
235 * On sync completion, the atom is returned. So on NULL return
236 * it's queued asynchronously.
237 */
9ff9de69 238 done = async_exec(sd->head, &sd->ahu);
bf0dc8fa 239
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240 if (done == (void *) -1) {
241 log_err("fio: syslets don't appear to work\n");
242 return -1;
243 }
244
9ff9de69 245 sd->head = sd->tail = NULL;
a4f4fdd7 246
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247 if (done)
248 fio_syslet_complete_atom(td, done);
a4f4fdd7 249
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250 return 0;
251}
252
253static int fio_syslet_queue(struct thread_data *td, struct io_u *io_u)
254{
255 struct syslet_data *sd = td->io_ops->data;
bf0dc8fa 256
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257 if (sd->tail) {
258 sd->tail->next = &io_u->req.atom;
259 sd->tail = &io_u->req.atom;
260 } else
261 sd->head = sd->tail = &io_u->req.atom;
a4f4fdd7 262
5b38ee84 263 io_u->req.head = sd->head;
9ff9de69 264 return FIO_Q_QUEUED;
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265}
266
db64e9bc 267static int async_head_init(struct syslet_data *sd, unsigned int depth)
a4f4fdd7 268{
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269 unsigned long ring_size;
270
bf0dc8fa 271 memset(&sd->ahu, 0, sizeof(struct async_head_user));
2ca50be4 272
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273 ring_size = sizeof(struct syslet_uatom *) * depth;
274 sd->ring = malloc(ring_size);
275 memset(sd->ring, 0, ring_size);
276
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277 sd->ahu.user_ring_idx = 0;
278 sd->ahu.completion_ring = sd->ring;
279 sd->ahu.ring_size_bytes = ring_size;
280 sd->ahu.head_stack = thread_stack_alloc();
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281 sd->ahu.head_eip = (unsigned long) cachemiss_thread_start;
282 sd->ahu.new_thread_eip = (unsigned long) cachemiss_thread_start;
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283
284 return 0;
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285}
286
2ca50be4 287static void async_head_exit(struct syslet_data *sd)
a4f4fdd7 288{
7f059a76 289 free(sd->ring);
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290}
291
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292static int check_syslet_support(struct syslet_data *sd)
293{
294 struct syslet_uatom atom;
295 void *ret;
296
297 init_atom(&atom, __NR_getpid, NULL, NULL, NULL, NULL, NULL, 0, NULL);
298 ret = async_exec(sd->head, &sd->ahu);
299 if (ret == (void *) -1)
300 return 1;
301
302 return 0;
303}
304
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305static void fio_syslet_cleanup(struct thread_data *td)
306{
307 struct syslet_data *sd = td->io_ops->data;
308
309 if (sd) {
2ca50be4 310 async_head_exit(sd);
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311 free(sd->events);
312 free(sd);
313 td->io_ops->data = NULL;
314 }
315}
316
317static int fio_syslet_init(struct thread_data *td)
318{
319 struct syslet_data *sd;
320
321 sd = malloc(sizeof(*sd));
322 memset(sd, 0, sizeof(*sd));
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323 sd->events = malloc(sizeof(struct io_u *) * td->o.iodepth);
324 memset(sd->events, 0, sizeof(struct io_u *) * td->o.iodepth);
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325
326 /*
327 * This will handily fail for kernels where syslet isn't available
328 */
2dc1bbeb 329 if (async_head_init(sd, td->o.iodepth)) {
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330 free(sd->events);
331 free(sd);
332 return 1;
333 }
334
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335 if (check_syslet_support(sd)) {
336 log_err("fio: syslets do not appear to work\n");
337 free(sd->events);
338 free(sd);
339 return 1;
340 }
341
a4f4fdd7 342 td->io_ops->data = sd;
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343 return 0;
344}
345
346static struct ioengine_ops ioengine = {
347 .name = "syslet-rw",
348 .version = FIO_IOOPS_VERSION,
349 .init = fio_syslet_init,
350 .prep = fio_syslet_prep,
351 .queue = fio_syslet_queue,
9ff9de69 352 .commit = fio_syslet_commit,
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353 .getevents = fio_syslet_getevents,
354 .event = fio_syslet_event,
355 .cleanup = fio_syslet_cleanup,
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356 .open_file = generic_open_file,
357 .close_file = generic_close_file,
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358};
359
360#else /* FIO_HAVE_SYSLET */
361
362/*
363 * When we have a proper configure system in place, we simply wont build
364 * and install this io engine. For now install a crippled version that
365 * just complains and fails to load.
366 */
367static int fio_syslet_init(struct thread_data fio_unused *td)
368{
369 fprintf(stderr, "fio: syslet not available\n");
370 return 1;
371}
372
373static struct ioengine_ops ioengine = {
374 .name = "syslet-rw",
375 .version = FIO_IOOPS_VERSION,
376 .init = fio_syslet_init,
377};
378
379#endif /* FIO_HAVE_SYSLET */
380
381static void fio_init fio_syslet_register(void)
382{
383 register_ioengine(&ioengine);
384}
385
386static void fio_exit fio_syslet_unregister(void)
387{
388 unregister_ioengine(&ioengine);
389}