sg engine: fix old comment
[fio.git] / engines / null.c
CommitLineData
a94ea28b 1/*
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2 * null engine
3 *
4 * IO engine that doesn't do any real IO transfers, it just pretends to.
5 * The main purpose is to test fio itself.
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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>
13
14#include "../fio.h"
15#include "../os.h"
16
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17struct null_data {
18 struct io_u **io_us;
19 int queued;
20 int events;
21};
22
23static struct io_u *fio_null_event(struct thread_data *td, int event)
24{
25 struct null_data *nd = td->io_ops->data;
26
27 return nd->io_us[event];
28}
29
7401c088 30static int fio_null_getevents(struct thread_data *td, int min_events,
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31 int fio_unused max, struct timespec fio_unused *t)
32{
33 struct null_data *nd = td->io_ops->data;
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34 int ret = 0;
35
36 if (min_events) {
37 ret = nd->events;
38 nd->events = 0;
39 }
65afa5f2 40
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41 return ret;
42}
43
44static int fio_null_commit(struct thread_data *td)
45{
46 struct null_data *nd = td->io_ops->data;
47
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48 if (!nd->events) {
49 nd->events = nd->queued;
50 nd->queued = 0;
51 }
52
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53 return 0;
54}
55
36167d82 56static int fio_null_queue(struct thread_data fio_unused *td, struct io_u *io_u)
a94ea28b 57{
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58 struct null_data *nd = td->io_ops->data;
59
60 if (td->io_ops->flags & FIO_SYNCIO)
61 return FIO_Q_COMPLETED;
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62 if (nd->events)
63 return FIO_Q_BUSY;
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64
65 nd->io_us[nd->queued++] = io_u;
66 return FIO_Q_QUEUED;
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67}
68
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69static int fio_null_setup(struct thread_data *td)
70{
71 struct fio_file *f;
af52b345 72 unsigned int i;
2fd233b7 73
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74 for_each_file(td, f, i)
75 f->real_file_size = -1ULL;
2fd233b7 76
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77 return 0;
78}
79
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80static int fio_null_open(struct thread_data fio_unused *td,
81 struct fio_file fio_unused *f)
82{
640e9421 83 f->fd = 0;
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84 return 0;
85}
86
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87static void fio_null_cleanup(struct thread_data *td)
88{
89 struct null_data *nd = td->io_ops->data;
90
91 if (nd) {
92 if (nd->io_us)
93 free(nd->io_us);
94 free(nd);
95 td->io_ops->data = NULL;
96 }
97}
98
99static int fio_null_init(struct thread_data *td)
100{
101 struct null_data *nd = malloc(sizeof(*nd));
102
103 memset(nd, 0, sizeof(*nd));
104
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105 if (td->o.iodepth != 1) {
106 nd->io_us = malloc(td->o.iodepth * sizeof(struct io_u *));
107 memset(nd->io_us, 0, td->o.iodepth * sizeof(struct io_u *));
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108 } else
109 td->io_ops->flags |= FIO_SYNCIO;
110
111 td->io_ops->data = nd;
112 return 0;
113}
114
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115static struct ioengine_ops ioengine = {
116 .name = "null",
117 .version = FIO_IOOPS_VERSION,
2fd233b7 118 .setup = fio_null_setup,
a94ea28b 119 .queue = fio_null_queue,
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120 .commit = fio_null_commit,
121 .getevents = fio_null_getevents,
122 .event = fio_null_event,
123 .init = fio_null_init,
124 .cleanup = fio_null_cleanup,
b5af8293 125 .open_file = fio_null_open,
65afa5f2 126 .flags = FIO_DISKLESSIO,
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127};
128
129static void fio_init fio_null_register(void)
130{
131 register_ioengine(&ioengine);
132}
133
134static void fio_exit fio_null_unregister(void)
135{
136 unregister_ioengine(&ioengine);
137}