Add possibility to make sequential IO "holed"
For sequential IO, it is now possible to add a number of bytes to
be skipped for every block read or written. Using:
bs=8k
rw=read:8k
will first read 0k->8k, then 16k->24k, and so on. This skips 8k
for every 'bs' sized block read. Similar for writes, doing
bs=4k
rw=write:4k
will write 0k->4k, then 8k->12k, etc. End result being that every
other block is written, in a sequential fashion.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/io_u.c b/io_u.c
index 51da223..6a53bda 100644
--- a/io_u.c
+++ b/io_u.c
@@ -249,7 +249,12 @@
assert(ddir_rw(ddir));
if (f->last_pos < f->real_file_size) {
- *b = (f->last_pos - f->file_offset) / td->o.min_bs[ddir];
+ unsigned long long pos = f->last_pos - f->file_offset;
+
+ if (pos)
+ pos += td->o.ddir_seq_add;
+
+ *b = pos / td->o.min_bs[ddir];
return 0;
}