1 /*
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.
6 *
7 * It also can act as external C++ engine - compiled with:
8 *
9 * g++ -O2 -g -shared -rdynamic -fPIC -o null.so null.c -DFIO_EXTERNAL_ENGINE
10 *
11 */
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <unistd.h>
15 #include <errno.h>
16 #include <assert.h>
17
18 #include "../fio.h"
19
20 struct null_data {
21 struct io_u **io_us;
22 int queued;
23 int events;
24 };
25
fio_null_event(struct thread_data * td,int event)26 static struct io_u *fio_null_event(struct thread_data *td, int event)
27 {
28 struct null_data *nd = (struct null_data *) td->io_ops_data;
29
30 return nd->io_us[event];
31 }
32
fio_null_getevents(struct thread_data * td,unsigned int min_events,unsigned int fio_unused max,const struct timespec fio_unused * t)33 static int fio_null_getevents(struct thread_data *td, unsigned int min_events,
34 unsigned int fio_unused max,
35 const struct timespec fio_unused *t)
36 {
37 struct null_data *nd = (struct null_data *) td->io_ops_data;
38 int ret = 0;
39
40 if (min_events) {
41 ret = nd->events;
42 nd->events = 0;
43 }
44
45 return ret;
46 }
47
fio_null_commit(struct thread_data * td)48 static int fio_null_commit(struct thread_data *td)
49 {
50 struct null_data *nd = (struct null_data *) td->io_ops_data;
51
52 if (!nd->events) {
53 #ifndef FIO_EXTERNAL_ENGINE
54 io_u_mark_submit(td, nd->queued);
55 #endif
56 nd->events = nd->queued;
57 nd->queued = 0;
58 }
59
60 return 0;
61 }
62
fio_null_queue(struct thread_data * td,struct io_u * io_u)63 static int fio_null_queue(struct thread_data *td, struct io_u *io_u)
64 {
65 struct null_data *nd = (struct null_data *) td->io_ops_data;
66
67 fio_ro_check(td, io_u);
68
69 if (td->io_ops->flags & FIO_SYNCIO)
70 return FIO_Q_COMPLETED;
71 if (nd->events)
72 return FIO_Q_BUSY;
73
74 nd->io_us[nd->queued++] = io_u;
75 return FIO_Q_QUEUED;
76 }
77
fio_null_open(struct thread_data fio_unused * td,struct fio_file fio_unused * f)78 static int fio_null_open(struct thread_data fio_unused *td,
79 struct fio_file fio_unused *f)
80 {
81 return 0;
82 }
83
fio_null_cleanup(struct thread_data * td)84 static void fio_null_cleanup(struct thread_data *td)
85 {
86 struct null_data *nd = (struct null_data *) td->io_ops_data;
87
88 if (nd) {
89 free(nd->io_us);
90 free(nd);
91 }
92 }
93
fio_null_init(struct thread_data * td)94 static int fio_null_init(struct thread_data *td)
95 {
96 struct null_data *nd = (struct null_data *) malloc(sizeof(*nd));
97
98 memset(nd, 0, sizeof(*nd));
99
100 if (td->o.iodepth != 1) {
101 nd->io_us = (struct io_u **) malloc(td->o.iodepth * sizeof(struct io_u *));
102 memset(nd->io_us, 0, td->o.iodepth * sizeof(struct io_u *));
103 } else
104 td->io_ops->flags |= FIO_SYNCIO;
105
106 td->io_ops_data = nd;
107 return 0;
108 }
109
110 #ifndef __cplusplus
111 static struct ioengine_ops ioengine = {
112 .name = "null",
113 .version = FIO_IOOPS_VERSION,
114 .queue = fio_null_queue,
115 .commit = fio_null_commit,
116 .getevents = fio_null_getevents,
117 .event = fio_null_event,
118 .init = fio_null_init,
119 .cleanup = fio_null_cleanup,
120 .open_file = fio_null_open,
121 .flags = FIO_DISKLESSIO | FIO_FAKEIO,
122 };
123
fio_null_register(void)124 static void fio_init fio_null_register(void)
125 {
126 register_ioengine(&ioengine);
127 }
128
fio_null_unregister(void)129 static void fio_exit fio_null_unregister(void)
130 {
131 unregister_ioengine(&ioengine);
132 }
133
134 #else
135
136 #ifdef FIO_EXTERNAL_ENGINE
137 extern "C" {
138 static struct ioengine_ops ioengine;
get_ioengine(struct ioengine_ops ** ioengine_ptr)139 void get_ioengine(struct ioengine_ops **ioengine_ptr)
140 {
141 *ioengine_ptr = &ioengine;
142
143 ioengine.name = "cpp_null";
144 ioengine.version = FIO_IOOPS_VERSION;
145 ioengine.queue = fio_null_queue;
146 ioengine.commit = fio_null_commit;
147 ioengine.getevents = fio_null_getevents;
148 ioengine.event = fio_null_event;
149 ioengine.init = fio_null_init;
150 ioengine.cleanup = fio_null_cleanup;
151 ioengine.open_file = fio_null_open;
152 ioengine.flags = FIO_DISKLESSIO | FIO_FAKEIO;
153 }
154 }
155 #endif /* FIO_EXTERNAL_ENGINE */
156
157 #endif /* __cplusplus */
158