fio HOWTO/man fix
[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"
a94ea28b 15
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16struct null_data {
17 struct io_u **io_us;
18 int queued;
19 int events;
20};
21
22static struct io_u *fio_null_event(struct thread_data *td, int event)
23{
24 struct null_data *nd = td->io_ops->data;
25
26 return nd->io_us[event];
27}
28
7401c088 29static int fio_null_getevents(struct thread_data *td, int min_events,
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30 int fio_unused max, struct timespec fio_unused *t)
31{
32 struct null_data *nd = td->io_ops->data;
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33 int ret = 0;
34
35 if (min_events) {
36 ret = nd->events;
37 nd->events = 0;
38 }
65afa5f2 39
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40 return ret;
41}
42
43static int fio_null_commit(struct thread_data *td)
44{
45 struct null_data *nd = td->io_ops->data;
46
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47 if (!nd->events) {
48 nd->events = nd->queued;
49 nd->queued = 0;
50 }
51
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52 return 0;
53}
54
36167d82 55static int fio_null_queue(struct thread_data fio_unused *td, struct io_u *io_u)
a94ea28b 56{
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57 struct null_data *nd = td->io_ops->data;
58
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59 fio_ro_check(td, io_u);
60
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61 if (td->io_ops->flags & FIO_SYNCIO)
62 return FIO_Q_COMPLETED;
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63 if (nd->events)
64 return FIO_Q_BUSY;
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65
66 nd->io_us[nd->queued++] = io_u;
67 return FIO_Q_QUEUED;
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68}
69
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70static int fio_null_open(struct thread_data fio_unused *td,
71 struct fio_file fio_unused *f)
72{
73 return 0;
74}
75
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76static void fio_null_cleanup(struct thread_data *td)
77{
78 struct null_data *nd = td->io_ops->data;
79
80 if (nd) {
81 if (nd->io_us)
82 free(nd->io_us);
83 free(nd);
84 td->io_ops->data = NULL;
85 }
86}
87
88static int fio_null_init(struct thread_data *td)
89{
90 struct null_data *nd = malloc(sizeof(*nd));
91
92 memset(nd, 0, sizeof(*nd));
93
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94 if (td->o.iodepth != 1) {
95 nd->io_us = malloc(td->o.iodepth * sizeof(struct io_u *));
96 memset(nd->io_us, 0, td->o.iodepth * sizeof(struct io_u *));
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97 } else
98 td->io_ops->flags |= FIO_SYNCIO;
99
100 td->io_ops->data = nd;
101 return 0;
102}
103
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104static struct ioengine_ops ioengine = {
105 .name = "null",
106 .version = FIO_IOOPS_VERSION,
a94ea28b 107 .queue = fio_null_queue,
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108 .commit = fio_null_commit,
109 .getevents = fio_null_getevents,
110 .event = fio_null_event,
111 .init = fio_null_init,
112 .cleanup = fio_null_cleanup,
b5af8293 113 .open_file = fio_null_open,
65afa5f2 114 .flags = FIO_DISKLESSIO,
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115};
116
117static void fio_init fio_null_register(void)
118{
119 register_ioengine(&ioengine);
120}
121
122static void fio_exit fio_null_unregister(void)
123{
124 unregister_ioengine(&ioengine);
125}