4 * IO engine that doesn't do any real IO transfers, it just pretends to.
5 * The main purpose is to test fio itself.
7 * It also can act as external C++ engine - compiled with:
9 * g++ -O2 -g -shared -rdynamic -fPIC -o null.so null.c -DFIO_EXTERNAL_ENGINE
26 static struct io_u *fio_null_event(struct thread_data *td, int event)
28 struct null_data *nd = (struct null_data *) td->io_ops_data;
30 return nd->io_us[event];
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)
37 struct null_data *nd = (struct null_data *) td->io_ops_data;
48 static int fio_null_commit(struct thread_data *td)
50 struct null_data *nd = (struct null_data *) td->io_ops_data;
53 #ifndef FIO_EXTERNAL_ENGINE
54 io_u_mark_submit(td, nd->queued);
56 nd->events = nd->queued;
63 static int fio_null_queue(struct thread_data *td, struct io_u *io_u)
65 struct null_data *nd = (struct null_data *) td->io_ops_data;
67 fio_ro_check(td, io_u);
69 if (td->io_ops->flags & FIO_SYNCIO)
70 return FIO_Q_COMPLETED;
74 nd->io_us[nd->queued++] = io_u;
78 static int fio_null_open(struct thread_data fio_unused *td,
79 struct fio_file fio_unused *f)
84 static void fio_null_cleanup(struct thread_data *td)
86 struct null_data *nd = (struct null_data *) td->io_ops_data;
94 static int fio_null_init(struct thread_data *td)
96 struct null_data *nd = (struct null_data *) malloc(sizeof(*nd));
98 memset(nd, 0, sizeof(*nd));
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 *));
104 td->io_ops->flags |= FIO_SYNCIO;
106 td->io_ops_data = nd;
111 static struct ioengine_ops ioengine = {
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,
124 static void fio_init fio_null_register(void)
126 register_ioengine(&ioengine);
129 static void fio_exit fio_null_unregister(void)
131 unregister_ioengine(&ioengine);
136 #ifdef FIO_EXTERNAL_ENGINE
138 static struct ioengine_ops ioengine;
139 void get_ioengine(struct ioengine_ops **ioengine_ptr)
141 *ioengine_ptr = &ioengine;
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;
155 #endif /* FIO_EXTERNAL_ENGINE */
157 #endif /* __cplusplus */