[PATCH] Update HOWTO
[fio.git] / io_u.c
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1#include <unistd.h>
2#include <fcntl.h>
3#include <string.h>
4#include <signal.h>
5#include <time.h>
6#include <assert.h>
7
8#include "fio.h"
9#include "os.h"
10
11/*
12 * The ->file_map[] contains a map of blocks we have or have not done io
13 * to yet. Used to make sure we cover the entire range in a fair fashion.
14 */
15static int random_map_free(struct thread_data *td, struct fio_file *f,
16 unsigned long long block)
17{
18 unsigned int idx = RAND_MAP_IDX(td, f, block);
19 unsigned int bit = RAND_MAP_BIT(td, f, block);
20
21 return (f->file_map[idx] & (1UL << bit)) == 0;
22}
23
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24/*
25 * Mark a given offset as used in the map.
26 */
27static void mark_random_map(struct thread_data *td, struct fio_file *f,
28 struct io_u *io_u)
29{
30 unsigned long long block = io_u->offset / (unsigned long long) td->min_bs;
31 unsigned int blocks = 0;
32
33 while (blocks < (io_u->buflen / td->min_bs)) {
34 unsigned int idx, bit;
35
36 if (!random_map_free(td, f, block))
37 break;
38
39 idx = RAND_MAP_IDX(td, f, block);
40 bit = RAND_MAP_BIT(td, f, block);
41
42 assert(idx < f->num_maps);
43
44 f->file_map[idx] |= (1UL << bit);
45 block++;
46 blocks++;
47 }
48
49 if ((blocks * td->min_bs) < io_u->buflen)
50 io_u->buflen = blocks * td->min_bs;
51}
52
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53/*
54 * Return the next free block in the map.
55 */
56static int get_next_free_block(struct thread_data *td, struct fio_file *f,
57 unsigned long long *b)
58{
59 int i;
60
61 *b = 0;
62 i = 0;
63 while ((*b) * td->min_bs < f->file_size) {
64 if (f->file_map[i] != -1UL) {
65 *b += ffz(f->file_map[i]);
66 return 0;
67 }
68
69 *b += BLOCKS_PER_MAP;
70 i++;
71 }
72
73 return 1;
74}
75
76/*
77 * For random io, generate a random new block and see if it's used. Repeat
78 * until we find a free one. For sequential io, just return the end of
79 * the last io issued.
80 */
81static int get_next_offset(struct thread_data *td, struct fio_file *f,
82 unsigned long long *offset)
83{
84 unsigned long long b, rb;
85 long r;
86
87 if (!td->sequential) {
88 unsigned long long max_blocks = td->io_size / td->min_bs;
89 int loops = 50;
90
91 do {
92 r = os_random_long(&td->random_state);
93 b = ((max_blocks - 1) * r / (unsigned long long) (RAND_MAX+1.0));
94 rb = b + (f->file_offset / td->min_bs);
95 loops--;
96 } while (!random_map_free(td, f, rb) && loops);
97
98 if (!loops) {
99 if (get_next_free_block(td, f, &b))
100 return 1;
101 }
102 } else
103 b = f->last_pos / td->min_bs;
104
105 *offset = (b * td->min_bs) + f->file_offset;
106 if (*offset > f->file_size)
107 return 1;
108
109 return 0;
110}
111
112static unsigned int get_next_buflen(struct thread_data *td)
113{
114 unsigned int buflen;
115 long r;
116
117 if (td->min_bs == td->max_bs)
118 buflen = td->min_bs;
119 else {
120 r = os_random_long(&td->bsrange_state);
121 buflen = (1 + (double) (td->max_bs - 1) * r / (RAND_MAX + 1.0));
122 buflen = (buflen + td->min_bs - 1) & ~(td->min_bs - 1);
123 }
124
125 if (buflen > td->io_size - td->this_io_bytes[td->ddir]) {
126 /*
127 * if using direct/raw io, we may not be able to
128 * shrink the size. so just fail it.
129 */
130 if (td->io_ops->flags & FIO_RAWIO)
131 return 0;
132
133 buflen = td->io_size - td->this_io_bytes[td->ddir];
134 }
135
136 return buflen;
137}
138
139/*
140 * Return the data direction for the next io_u. If the job is a
141 * mixed read/write workload, check the rwmix cycle and switch if
142 * necessary.
143 */
144static int get_rw_ddir(struct thread_data *td)
145{
146 if (td_rw(td)) {
147 struct timeval now;
148 unsigned long elapsed;
149
150 gettimeofday(&now, NULL);
151 elapsed = mtime_since_now(&td->rwmix_switch);
152
153 /*
154 * Check if it's time to seed a new data direction.
155 */
156 if (elapsed >= td->rwmixcycle) {
157 unsigned int v;
158 long r;
159
160 r = os_random_long(&td->rwmix_state);
161 v = 1 + (int) (100.0 * (r / (RAND_MAX + 1.0)));
162 if (v < td->rwmixread)
163 td->rwmix_ddir = DDIR_READ;
164 else
165 td->rwmix_ddir = DDIR_WRITE;
166 memcpy(&td->rwmix_switch, &now, sizeof(now));
167 }
168 return td->rwmix_ddir;
169 } else if (td_read(td))
170 return DDIR_READ;
171 else
172 return DDIR_WRITE;
173}
174
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175void put_io_u(struct thread_data *td, struct io_u *io_u)
176{
177 io_u->file = NULL;
178 list_del(&io_u->list);
179 list_add(&io_u->list, &td->io_u_freelist);
180 td->cur_depth--;
181}
182
183static int fill_io_u(struct thread_data *td, struct fio_file *f,
184 struct io_u *io_u)
185{
186 /*
187 * If using an iolog, grab next piece if any available.
188 */
189 if (td->read_iolog)
190 return read_iolog_get(td, io_u);
191
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192 /*
193 * see if it's time to sync
194 */
195 if (td->fsync_blocks && !(td->io_blocks[DDIR_WRITE] % td->fsync_blocks)
196 && should_fsync(td)) {
197 io_u->ddir = DDIR_SYNC;
198 io_u->file = f;
199 return 0;
200 }
201
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202 /*
203 * No log, let the seq/rand engine retrieve the next position.
204 */
205 if (!get_next_offset(td, f, &io_u->offset)) {
206 io_u->buflen = get_next_buflen(td);
207
208 if (io_u->buflen) {
209 io_u->ddir = get_rw_ddir(td);
210
211 /*
212 * If using a write iolog, store this entry.
213 */
214 if (td->write_iolog)
215 write_iolog_put(td, io_u);
216
217 io_u->file = f;
218 return 0;
219 }
220 }
221
222 return 1;
223}
224
225struct io_u *__get_io_u(struct thread_data *td)
226{
227 struct io_u *io_u = NULL;
228
229 if (!queue_full(td)) {
230 io_u = list_entry(td->io_u_freelist.next, struct io_u, list);
231
6040dabc 232 io_u->buflen = 0;
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233 io_u->error = 0;
234 io_u->resid = 0;
235 list_del(&io_u->list);
236 list_add(&io_u->list, &td->io_u_busylist);
237 td->cur_depth++;
238 }
239
240 return io_u;
241}
242
243/*
244 * Return an io_u to be processed. Gets a buflen and offset, sets direction,
245 * etc. The returned io_u is fully ready to be prepped and submitted.
246 */
247struct io_u *get_io_u(struct thread_data *td, struct fio_file *f)
248{
249 struct io_u *io_u;
250
251 io_u = __get_io_u(td);
252 if (!io_u)
253 return NULL;
254
255 if (td->zone_bytes >= td->zone_size) {
256 td->zone_bytes = 0;
257 f->last_pos += td->zone_skip;
258 }
259
260 if (fill_io_u(td, f, io_u)) {
261 put_io_u(td, io_u);
262 return NULL;
263 }
264
265 if (io_u->buflen + io_u->offset > f->file_size) {
266 if (td->io_ops->flags & FIO_RAWIO) {
267 put_io_u(td, io_u);
268 return NULL;
269 }
270
271 io_u->buflen = f->file_size - io_u->offset;
272 }
273
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274 if (io_u->ddir != DDIR_SYNC) {
275 if (!io_u->buflen) {
276 put_io_u(td, io_u);
277 return NULL;
278 }
10ba535a 279
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280 if (!td->read_iolog && !td->sequential)
281 mark_random_map(td, f, io_u);
10ba535a 282
87dc1ab1 283 f->last_pos += io_u->buflen;
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285 if (td->verify != VERIFY_NONE)
286 populate_verify_io_u(td, io_u);
287 }
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288
289 if (td_io_prep(td, io_u)) {
290 put_io_u(td, io_u);
291 return NULL;
292 }
293
294 gettimeofday(&io_u->start_time, NULL);
295 return io_u;
296}
297
298void io_completed(struct thread_data *td, struct io_u *io_u,
299 struct io_completion_data *icd)
300{
301 struct timeval e;
302 unsigned long msec;
303
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304 if (io_u->ddir == DDIR_SYNC) {
305 td->last_was_sync = 1;
306 return;
307 }
308
309 td->last_was_sync = 0;
310
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311 gettimeofday(&e, NULL);
312
313 if (!io_u->error) {
314 unsigned int bytes = io_u->buflen - io_u->resid;
315 const int idx = io_u->ddir;
316
317 td->io_blocks[idx]++;
318 td->io_bytes[idx] += bytes;
319 td->zone_bytes += bytes;
320 td->this_io_bytes[idx] += bytes;
321
322 msec = mtime_since(&io_u->issue_time, &e);
323
324 add_clat_sample(td, idx, msec);
325 add_bw_sample(td, idx);
326
327 if ((td_rw(td) || td_write(td)) && idx == DDIR_WRITE)
328 log_io_piece(td, io_u);
329
330 icd->bytes_done[idx] += bytes;
331 } else
332 icd->error = io_u->error;
333}
334
335void ios_completed(struct thread_data *td, struct io_completion_data *icd)
336{
337 struct io_u *io_u;
338 int i;
339
340 icd->error = 0;
341 icd->bytes_done[0] = icd->bytes_done[1] = 0;
342
343 for (i = 0; i < icd->nr; i++) {
344 io_u = td->io_ops->event(td, i);
345
346 io_completed(td, io_u, icd);
347 put_io_u(td, io_u);
348 }
349}
350
351