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 | * | |
44364a99 | 6 | * gcc -Wall -O2 -g -D_GNU_SOURCE -include ../config-host.h -shared -rdynamic -fPIC -o skeleton_external.o skeleton_external.c |
d243fd6d | 7 | * (also requires -D_GNU_SOURCE -DCONFIG_STRSEP on Linux) |
da51c050 JA |
8 | * |
9 | */ | |
10 | #include <stdio.h> | |
11 | #include <stdlib.h> | |
12 | #include <unistd.h> | |
13 | #include <errno.h> | |
14 | #include <assert.h> | |
15 | ||
16 | #include "../fio.h" | |
d243fd6d | 17 | #include "../optgroup.h" |
da51c050 JA |
18 | |
19 | /* | |
20 | * The core of the module is identical to the ones included with fio, | |
21 | * read those. You cannot use register_ioengine() and unregister_ioengine() | |
22 | * for external modules, they should be gotten through dlsym() | |
23 | */ | |
24 | ||
d243fd6d TK |
25 | /* |
26 | * The io engine can define its own options within the io engine source. | |
27 | * The option member must not be at offset 0, due to the way fio parses | |
28 | * the given option. Just add a padding pointer unless the io engine has | |
29 | * something usable. | |
30 | */ | |
31 | struct fio_skeleton_options { | |
32 | void *pad; /* avoid ->off1 of fio_option becomes 0 */ | |
33 | unsigned int dummy; | |
34 | }; | |
35 | ||
36 | static struct fio_option options[] = { | |
37 | { | |
38 | .name = "dummy", | |
39 | .lname = "ldummy", | |
40 | .type = FIO_OPT_STR_SET, | |
41 | .off1 = offsetof(struct fio_skeleton_options, dummy), | |
42 | .help = "Set dummy", | |
43 | .category = FIO_OPT_C_ENGINE, /* always use this */ | |
44 | .group = FIO_OPT_G_INVALID, /* this can be different */ | |
45 | }, | |
46 | { | |
47 | .name = NULL, | |
48 | }, | |
49 | }; | |
50 | ||
830a78b0 JA |
51 | /* |
52 | * The ->event() hook is called to match an event number with an io_u. | |
53 | * After the core has called ->getevents() and it has returned eg 3, | |
54 | * the ->event() hook must return the 3 events that have completed for | |
55 | * subsequent calls to ->event() with [0-2]. Required. | |
56 | */ | |
57 | static struct io_u *fio_skeleton_event(struct thread_data *td, int event) | |
58 | { | |
59 | return NULL; | |
60 | } | |
61 | ||
62 | /* | |
63 | * The ->getevents() hook is used to reap completion events from an async | |
64 | * io engine. It returns the number of completed events since the last call, | |
65 | * which may then be retrieved by calling the ->event() hook with the event | |
66 | * numbers. Required. | |
67 | */ | |
e7d2e616 | 68 | static int fio_skeleton_getevents(struct thread_data *td, unsigned int min, |
1f440ece | 69 | unsigned int max, const struct timespec *t) |
830a78b0 JA |
70 | { |
71 | return 0; | |
72 | } | |
73 | ||
74 | /* | |
75 | * The ->cancel() hook attempts to cancel the io_u. Only relevant for | |
76 | * async io engines, and need not be supported. | |
77 | */ | |
78 | static int fio_skeleton_cancel(struct thread_data *td, struct io_u *io_u) | |
79 | { | |
80 | return 0; | |
81 | } | |
82 | ||
83 | /* | |
84 | * The ->queue() hook is responsible for initiating io on the io_u | |
85 | * being passed in. If the io engine is a synchronous one, io may complete | |
86 | * before ->queue() returns. Required. | |
e2a26d2c JA |
87 | * |
88 | * The io engine must transfer in the direction noted by io_u->ddir | |
89 | * to the buffer pointed to by io_u->xfer_buf for as many bytes as | |
03e20d68 | 90 | * io_u->xfer_buflen. Residual data count may be set in io_u->resid |
36167d82 | 91 | * for a short read/write. |
830a78b0 | 92 | */ |
2e4ef4fb JA |
93 | static enum fio_q_status fio_skeleton_queue(struct thread_data *td, |
94 | struct io_u *io_u) | |
830a78b0 | 95 | { |
7101d9c2 JA |
96 | /* |
97 | * Double sanity check to catch errant write on a readonly setup | |
98 | */ | |
99 | fio_ro_check(td, io_u); | |
100 | ||
36167d82 JA |
101 | /* |
102 | * Could return FIO_Q_QUEUED for a queued request, | |
103 | * FIO_Q_COMPLETED for a completed request, and FIO_Q_BUSY | |
104 | * if we could queue no more at this point (you'd have to | |
105 | * define ->commit() to handle that. | |
106 | */ | |
107 | return FIO_Q_COMPLETED; | |
830a78b0 JA |
108 | } |
109 | ||
110 | /* | |
111 | * The ->prep() function is called for each io_u prior to being submitted | |
112 | * with ->queue(). This hook allows the io engine to perform any | |
34403fb1 | 113 | * preparatory actions on the io_u, before being submitted. Not required. |
830a78b0 JA |
114 | */ |
115 | static int fio_skeleton_prep(struct thread_data *td, struct io_u *io_u) | |
116 | { | |
117 | return 0; | |
118 | } | |
119 | ||
120 | /* | |
121 | * The init function is called once per thread/process, and should set up | |
122 | * any structures that this io engine requires to keep track of io. Not | |
123 | * required. | |
124 | */ | |
125 | static int fio_skeleton_init(struct thread_data *td) | |
126 | { | |
127 | return 0; | |
128 | } | |
129 | ||
130 | /* | |
de8f6de9 | 131 | * This is paired with the ->init() function and is called when a thread is |
830a78b0 JA |
132 | * done doing io. Should tear down anything setup by the ->init() function. |
133 | * Not required. | |
134 | */ | |
135 | static void fio_skeleton_cleanup(struct thread_data *td) | |
136 | { | |
137 | } | |
138 | ||
b5af8293 JA |
139 | /* |
140 | * Hook for opening the given file. Unless the engine has special | |
2201299e | 141 | * needs, it usually just provides generic_open_file() as the handler. |
b5af8293 JA |
142 | */ |
143 | static int fio_skeleton_open(struct thread_data *td, struct fio_file *f) | |
144 | { | |
2201299e | 145 | return generic_open_file(td, f); |
b5af8293 JA |
146 | } |
147 | ||
148 | /* | |
149 | * Hook for closing a file. See fio_skeleton_open(). | |
150 | */ | |
151 | static int fio_skeleton_close(struct thread_data *td, struct fio_file *f) | |
152 | { | |
2201299e | 153 | return generic_close_file(td, f); |
b5af8293 JA |
154 | } |
155 | ||
da51c050 JA |
156 | /* |
157 | * Note that the structure is exported, so that fio can get it via | |
13690c10 | 158 | * dlsym(..., "ioengine"); for (and only for) external engines. |
da51c050 JA |
159 | */ |
160 | struct ioengine_ops ioengine = { | |
161 | .name = "engine_name", | |
162 | .version = FIO_IOOPS_VERSION, | |
163 | .init = fio_skeleton_init, | |
164 | .prep = fio_skeleton_prep, | |
165 | .queue = fio_skeleton_queue, | |
830a78b0 | 166 | .cancel = fio_skeleton_cancel, |
da51c050 JA |
167 | .getevents = fio_skeleton_getevents, |
168 | .event = fio_skeleton_event, | |
169 | .cleanup = fio_skeleton_cleanup, | |
b5af8293 JA |
170 | .open_file = fio_skeleton_open, |
171 | .close_file = fio_skeleton_close, | |
d243fd6d TK |
172 | .options = options, |
173 | .option_struct_size = sizeof(struct fio_skeleton_options), | |
da51c050 | 174 | }; |