Add option to select how to service multiple files

[fio.git] / io_u.c

diff --git a/io_u.c b/io_u.c
index ab85193d1c95166dfcbd4eeea45a28637c788d4c..6fb754e7f44701cbfddc628abe4f7164eeccd1aa 100644 (file)
--- a/io_u.c
+++ b/io_u.c
@@ -325,7 +325,27 @@ static void io_u_mark_latency(struct thread_data *td, unsigned long msec)
        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 @@ struct io_u *get_io_u(struct thread_data *td)
        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;