Add option to select how to service multiple files
Right now we just round robin the open files, but sometimes you
just want to randomly go through the files. Add a 'file_service'
option for that, default to round robin still.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/io_u.c b/io_u.c
index ab85193..6fb754e 100644
--- a/io_u.c
+++ b/io_u.c
@@ -325,7 +325,27 @@
td->io_u_lat[index]++;
}
-static struct fio_file *get_next_file(struct thread_data *td)
+/*
+ * Get next file to service by choosing one at random
+ */
+static struct fio_file *get_next_file_rand(struct thread_data *td)
+{
+ long r = os_random_long(&td->next_file_state);
+ unsigned int fileno;
+ struct fio_file *f;
+
+ do {
+ fileno = (unsigned int) ((double) (td->nr_files - 1) * r / (RAND_MAX + 1.0));
+ f = &td->files[fileno];
+ if (f->fd != -1)
+ return f;
+ } while (1);
+}
+
+/*
+ * Get next file to service by doing round robin between all available ones
+ */
+static struct fio_file *get_next_file_rr(struct thread_data *td)
{
unsigned int old_next_file = td->next_file;
struct fio_file *f;
@@ -393,7 +413,11 @@
if (io_u->file)
goto out;
- f = get_next_file(td);
+ if (td->file_service_type == FIO_FSERVICE_RR)
+ f = get_next_file_rr(td);
+ else
+ f = get_next_file_rand(td);
+
if (!f) {
put_io_u(td, io_u);
return NULL;