Add option for refilling IO buffers on each submit
If the device looks at whether the data changed, then this can
make a difference.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/io_u.c b/io_u.c
index 92cdd71..06fb3ce 100644
--- a/io_u.c
+++ b/io_u.c
@@ -6,6 +6,7 @@
#include <assert.h>
#include "fio.h"
+#include "hash.h"
/*
* Change this define to play with the timeout handling
@@ -780,6 +781,9 @@
io_u->endpos = io_u->offset + io_u->buflen;
io_u->xfer_buf = io_u->buf;
io_u->xfer_buflen = io_u->buflen;
+
+ if (td->o.refill_buffers && io_u->ddir == DDIR_WRITE)
+ io_u_fill_buffer(td, io_u, io_u->xfer_buflen);
out:
if (!td_io_prep(td, io_u)) {
fio_gettime(&io_u->start_time, NULL);
@@ -943,6 +947,23 @@
add_slat_sample(td, io_u->ddir, slat_time);
}
+/*
+ * "randomly" fill the buffer contents
+ */
+void io_u_fill_buffer(struct thread_data *td, struct io_u *io_u,
+ unsigned int max_bs)
+{
+ long *ptr = io_u->buf;
+
+ if (!td->o.zero_buffers) {
+ while ((void *) ptr - io_u->buf < max_bs) {
+ *ptr = rand() * GOLDEN_RATIO_PRIME;
+ ptr++;
+ }
+ } else
+ memset(ptr, 0, max_bs);
+}
+
#ifdef FIO_USE_TIMEOUT
void io_u_set_timeout(struct thread_data *td)
{