Commit | Line | Data |
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da51c050 JA |
1 | /* |
2 | * Skeleton for a sample external io engine | |
3 | * | |
4 | * Should be compiled with: | |
5 | * | |
6 | * gcc -Wall -O2 -g -shared -rdynamic -fPIC -o engine.o engine.c | |
7 | * | |
8 | */ | |
9 | #include <stdio.h> | |
10 | #include <stdlib.h> | |
11 | #include <unistd.h> | |
12 | #include <errno.h> | |
13 | #include <assert.h> | |
14 | ||
15 | #include "../fio.h" | |
da51c050 JA |
16 | |
17 | /* | |
18 | * The core of the module is identical to the ones included with fio, | |
19 | * read those. You cannot use register_ioengine() and unregister_ioengine() | |
20 | * for external modules, they should be gotten through dlsym() | |
21 | */ | |
22 | ||
830a78b0 JA |
23 | /* |
24 | * The ->event() hook is called to match an event number with an io_u. | |
25 | * After the core has called ->getevents() and it has returned eg 3, | |
26 | * the ->event() hook must return the 3 events that have completed for | |
27 | * subsequent calls to ->event() with [0-2]. Required. | |
28 | */ | |
29 | static struct io_u *fio_skeleton_event(struct thread_data *td, int event) | |
30 | { | |
31 | return NULL; | |
32 | } | |
33 | ||
34 | /* | |
35 | * The ->getevents() hook is used to reap completion events from an async | |
36 | * io engine. It returns the number of completed events since the last call, | |
37 | * which may then be retrieved by calling the ->event() hook with the event | |
38 | * numbers. Required. | |
39 | */ | |
e7d2e616 JA |
40 | static int fio_skeleton_getevents(struct thread_data *td, unsigned int min, |
41 | unsigned int max, struct timespec *t) | |
830a78b0 JA |
42 | { |
43 | return 0; | |
44 | } | |
45 | ||
46 | /* | |
47 | * The ->cancel() hook attempts to cancel the io_u. Only relevant for | |
48 | * async io engines, and need not be supported. | |
49 | */ | |
50 | static int fio_skeleton_cancel(struct thread_data *td, struct io_u *io_u) | |
51 | { | |
52 | return 0; | |
53 | } | |
54 | ||
55 | /* | |
56 | * The ->queue() hook is responsible for initiating io on the io_u | |
57 | * being passed in. If the io engine is a synchronous one, io may complete | |
58 | * before ->queue() returns. Required. | |
e2a26d2c JA |
59 | * |
60 | * The io engine must transfer in the direction noted by io_u->ddir | |
61 | * to the buffer pointed to by io_u->xfer_buf for as many bytes as | |
03e20d68 | 62 | * io_u->xfer_buflen. Residual data count may be set in io_u->resid |
36167d82 | 63 | * for a short read/write. |
830a78b0 JA |
64 | */ |
65 | static int fio_skeleton_queue(struct thread_data *td, struct io_u *io_u) | |
66 | { | |
7101d9c2 JA |
67 | /* |
68 | * Double sanity check to catch errant write on a readonly setup | |
69 | */ | |
70 | fio_ro_check(td, io_u); | |
71 | ||
36167d82 JA |
72 | /* |
73 | * Could return FIO_Q_QUEUED for a queued request, | |
74 | * FIO_Q_COMPLETED for a completed request, and FIO_Q_BUSY | |
75 | * if we could queue no more at this point (you'd have to | |
76 | * define ->commit() to handle that. | |
77 | */ | |
78 | return FIO_Q_COMPLETED; | |
830a78b0 JA |
79 | } |
80 | ||
81 | /* | |
82 | * The ->prep() function is called for each io_u prior to being submitted | |
83 | * with ->queue(). This hook allows the io engine to perform any | |
34403fb1 | 84 | * preparatory actions on the io_u, before being submitted. Not required. |
830a78b0 JA |
85 | */ |
86 | static int fio_skeleton_prep(struct thread_data *td, struct io_u *io_u) | |
87 | { | |
88 | return 0; | |
89 | } | |
90 | ||
91 | /* | |
92 | * The init function is called once per thread/process, and should set up | |
93 | * any structures that this io engine requires to keep track of io. Not | |
94 | * required. | |
95 | */ | |
96 | static int fio_skeleton_init(struct thread_data *td) | |
97 | { | |
98 | return 0; | |
99 | } | |
100 | ||
101 | /* | |
de8f6de9 | 102 | * This is paired with the ->init() function and is called when a thread is |
830a78b0 JA |
103 | * done doing io. Should tear down anything setup by the ->init() function. |
104 | * Not required. | |
105 | */ | |
106 | static void fio_skeleton_cleanup(struct thread_data *td) | |
107 | { | |
108 | } | |
109 | ||
b5af8293 JA |
110 | /* |
111 | * Hook for opening the given file. Unless the engine has special | |
112 | * needs, it usually just provides generic_file_open() as the handler. | |
113 | */ | |
114 | static int fio_skeleton_open(struct thread_data *td, struct fio_file *f) | |
115 | { | |
116 | return generic_file_open(td, f); | |
117 | } | |
118 | ||
119 | /* | |
120 | * Hook for closing a file. See fio_skeleton_open(). | |
121 | */ | |
122 | static int fio_skeleton_close(struct thread_data *td, struct fio_file *f) | |
123 | { | |
124 | generic_file_close(td, f); | |
125 | } | |
126 | ||
da51c050 JA |
127 | /* |
128 | * Note that the structure is exported, so that fio can get it via | |
129 | * dlsym(..., "ioengine"); | |
130 | */ | |
131 | struct ioengine_ops ioengine = { | |
132 | .name = "engine_name", | |
133 | .version = FIO_IOOPS_VERSION, | |
134 | .init = fio_skeleton_init, | |
135 | .prep = fio_skeleton_prep, | |
136 | .queue = fio_skeleton_queue, | |
830a78b0 | 137 | .cancel = fio_skeleton_cancel, |
da51c050 JA |
138 | .getevents = fio_skeleton_getevents, |
139 | .event = fio_skeleton_event, | |
140 | .cleanup = fio_skeleton_cleanup, | |
b5af8293 JA |
141 | .open_file = fio_skeleton_open, |
142 | .close_file = fio_skeleton_close, | |
da51c050 | 143 | }; |