[PATCH] Support for splice IO engine
diff --git a/fio-io.c b/fio-io.c
index aaf8fe1..f3606e1 100644
--- a/fio-io.c
+++ b/fio-io.c
@@ -751,3 +751,161 @@
}
#endif /* FIO_HAVE_SGIO */
+
+#ifdef FIO_HAVE_SPLICE
+struct spliceio_data {
+ struct io_u *last_io_u;
+ int pipe[2];
+};
+
+static struct io_u *fio_spliceio_event(struct thread_data *td, int event)
+{
+ struct syncio_data *sd = td->io_data;
+
+ assert(event == 0);
+
+ return sd->last_io_u;
+}
+
+/*
+ * For splice reading, we unfortunately cannot (yet) vmsplice the other way.
+ * So just splice the data from the file into the pipe, and use regular
+ * read to fill the buffer. Doesn't make a lot of sense, but...
+ */
+static int fio_splice_read(struct thread_data *td, struct io_u *io_u)
+{
+ struct spliceio_data *sd = td->io_data;
+ int ret, ret2, buflen;
+ void *p;
+
+ buflen = io_u->buflen;
+ p = io_u->buf;
+ do {
+ off_t off = io_u->offset;
+
+ ret = splice(td->fd, &off, sd->pipe[1], NULL, buflen, 0);
+ if (ret < 0)
+ return errno;
+
+ buflen -= ret;
+
+ while (ret) {
+ ret2 = read(sd->pipe[0], p, ret);
+ if (ret2 < 0)
+ return errno;
+
+ ret -= ret2;
+ p += ret2;
+ }
+ } while (buflen);
+
+ return io_u->buflen;
+}
+
+/*
+ * For splice writing, we can vmsplice our data buffer directly into a
+ * pipe and then splice that to a file.
+ */
+static int fio_splice_write(struct thread_data *td, struct io_u *io_u)
+{
+ struct spliceio_data *sd = td->io_data;
+ struct iovec iov[1] = {
+ {
+ .iov_base = io_u->buf,
+ .iov_len = io_u->buflen,
+ }
+ };
+ struct pollfd pfd = { .fd = sd->pipe[1], .events = POLLOUT, };
+ int ret, ret2;
+
+ while (iov[0].iov_len) {
+ if (poll(&pfd, 1, -1) < 0)
+ return errno;
+
+ ret = vmsplice(sd->pipe[1], iov, 1, SPLICE_F_NONBLOCK);
+ if (ret < 0)
+ return errno;
+
+ iov[0].iov_len -= ret;
+ iov[0].iov_base += ret;
+
+ while (ret) {
+ off_t off = io_u->offset;
+
+ ret2 = splice(sd->pipe[0], NULL, td->fd, &off, ret, 0);
+ if (ret2 < 0)
+ return errno;
+
+ ret -= ret2;
+ }
+ }
+
+ return io_u->buflen;
+}
+
+static int fio_spliceio_queue(struct thread_data *td, struct io_u *io_u)
+{
+ struct spliceio_data *sd = td->io_data;
+ int ret;
+
+ if (io_u->ddir == DDIR_READ)
+ ret = fio_splice_read(td, io_u);
+ else
+ ret = fio_splice_write(td, io_u);
+
+ if ((unsigned int) ret != io_u->buflen) {
+ if (ret > 0) {
+ io_u->resid = io_u->buflen - ret;
+ io_u->error = ENODATA;
+ } else
+ io_u->error = errno;
+ }
+
+ if (!io_u->error)
+ sd->last_io_u = io_u;
+
+ return io_u->error;
+}
+
+static void fio_spliceio_cleanup(struct thread_data *td)
+{
+ struct spliceio_data *sd = td->io_data;
+
+ if (sd) {
+ close(sd->pipe[0]);
+ close(sd->pipe[1]);
+ free(sd);
+ td->io_data = NULL;
+ }
+}
+
+int fio_spliceio_init(struct thread_data *td)
+{
+ struct spliceio_data *sd = malloc(sizeof(*sd));
+
+ td->io_queue = fio_spliceio_queue;
+ td->io_getevents = fio_syncio_getevents;
+ td->io_event = fio_spliceio_event;
+ td->io_cancel = NULL;
+ td->io_cleanup = fio_spliceio_cleanup;
+ td->io_sync = fio_io_sync;
+
+ sd->last_io_u = NULL;
+ if (pipe(sd->pipe) < 0) {
+ td_verror(td, errno);
+ free(sd);
+ return 1;
+ }
+
+ td->io_data = sd;
+ return 0;
+}
+
+#else /* FIO_HAVE_SPLICE */
+
+int fio_spliceio_init(struct thread_data *td)
+{
+ return EINVAL;
+}
+
+#endif /* FIO_HAVE_SPLICE */