[PATCH] Document filename= option
[fio.git] / engines / fio-engine-splice.c
CommitLineData
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1/*
2 * splice io engine
3 *
4 */
5#include <stdio.h>
6#include <stdlib.h>
7#include <unistd.h>
8#include <errno.h>
9#include <assert.h>
10#include <sys/poll.h>
11#include "fio.h"
12#include "os.h"
13
14struct spliceio_data {
15 struct io_u *last_io_u;
16 int pipe[2];
17};
18
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19static int fio_spliceio_getevents(struct thread_data *td, int fio_unused min,
20 int max, struct timespec fio_unused *t)
21{
22 assert(max <= 1);
23
24 /*
25 * we can only have one finished io_u for sync io, since the depth
26 * is always 1
27 */
28 if (list_empty(&td->io_u_busylist))
29 return 0;
30
31 return 1;
32}
33
34static struct io_u *fio_spliceio_event(struct thread_data *td, int event)
35{
36 struct spliceio_data *sd = td->io_ops->data;
37
38 assert(event == 0);
39
40 return sd->last_io_u;
41}
42
43/*
44 * For splice reading, we unfortunately cannot (yet) vmsplice the other way.
45 * So just splice the data from the file into the pipe, and use regular
46 * read to fill the buffer. Doesn't make a lot of sense, but...
47 */
48static int fio_splice_read(struct thread_data *td, struct io_u *io_u)
49{
50 struct spliceio_data *sd = td->io_ops->data;
53cdc686 51 struct fio_file *f = io_u->file;
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52 int ret, ret2, buflen;
53 off_t offset;
54 void *p;
55
56 offset = io_u->offset;
57 buflen = io_u->buflen;
58 p = io_u->buf;
59 while (buflen) {
60 int this_len = buflen;
61
62 if (this_len > SPLICE_DEF_SIZE)
63 this_len = SPLICE_DEF_SIZE;
64
53cdc686 65 ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len, SPLICE_F_MORE);
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66 if (ret < 0) {
67 if (errno == ENODATA || errno == EAGAIN)
68 continue;
69
70 return errno;
71 }
72
73 buflen -= ret;
74
75 while (ret) {
76 ret2 = read(sd->pipe[0], p, ret);
77 if (ret2 < 0)
78 return errno;
79
80 ret -= ret2;
81 p += ret2;
82 }
83 }
84
85 return io_u->buflen;
86}
87
88/*
89 * For splice writing, we can vmsplice our data buffer directly into a
90 * pipe and then splice that to a file.
91 */
92static int fio_splice_write(struct thread_data *td, struct io_u *io_u)
93{
94 struct spliceio_data *sd = td->io_ops->data;
95 struct iovec iov[1] = {
96 {
97 .iov_base = io_u->buf,
98 .iov_len = io_u->buflen,
99 }
100 };
101 struct pollfd pfd = { .fd = sd->pipe[1], .events = POLLOUT, };
53cdc686 102 struct fio_file *f = io_u->file;
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103 off_t off = io_u->offset;
104 int ret, ret2;
105
106 while (iov[0].iov_len) {
107 if (poll(&pfd, 1, -1) < 0)
108 return errno;
109
110 ret = vmsplice(sd->pipe[1], iov, 1, SPLICE_F_NONBLOCK);
111 if (ret < 0)
112 return errno;
113
114 iov[0].iov_len -= ret;
115 iov[0].iov_base += ret;
116
117 while (ret) {
53cdc686 118 ret2 = splice(sd->pipe[0], NULL, f->fd, &off, ret, 0);
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119 if (ret2 < 0)
120 return errno;
121
122 ret -= ret2;
123 }
124 }
125
126 return io_u->buflen;
127}
128
129static int fio_spliceio_queue(struct thread_data *td, struct io_u *io_u)
130{
131 struct spliceio_data *sd = td->io_ops->data;
132 int ret;
133
134 if (io_u->ddir == DDIR_READ)
135 ret = fio_splice_read(td, io_u);
87dc1ab1 136 else if (io_u->ddir == DDIR_WRITE)
2866c82d 137 ret = fio_splice_write(td, io_u);
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138 else
139 ret = fsync(io_u->file->fd);
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140
141 if ((unsigned int) ret != io_u->buflen) {
142 if (ret > 0) {
143 io_u->resid = io_u->buflen - ret;
144 io_u->error = ENODATA;
145 } else
146 io_u->error = errno;
147 }
148
149 if (!io_u->error)
150 sd->last_io_u = io_u;
151
152 return io_u->error;
153}
154
155static void fio_spliceio_cleanup(struct thread_data *td)
156{
157 struct spliceio_data *sd = td->io_ops->data;
158
159 if (sd) {
160 close(sd->pipe[0]);
161 close(sd->pipe[1]);
162 free(sd);
163 td->io_ops->data = NULL;
164 }
165}
166
167static int fio_spliceio_init(struct thread_data *td)
168{
169 struct spliceio_data *sd = malloc(sizeof(*sd));
170
171 sd->last_io_u = NULL;
172 if (pipe(sd->pipe) < 0) {
173 td_verror(td, errno);
174 free(sd);
175 return 1;
176 }
177
178 td->io_ops->data = sd;
179 return 0;
180}
181
182struct ioengine_ops ioengine = {
183 .name = "splice",
184 .version = FIO_IOOPS_VERSION,
185 .init = fio_spliceio_init,
186 .queue = fio_spliceio_queue,
187 .getevents = fio_spliceio_getevents,
188 .event = fio_spliceio_event,
189 .cleanup = fio_spliceio_cleanup,
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190 .flags = FIO_SYNCIO,
191};