Existing random zone index generation logic is dependent on the file size.
For smaller I/O sizes the random zone index always return a particular
section of open zones. As this index is used to return one of the open zones,
it was observed that after one of the max_open_zones / job_max_open_zones limit
is reached all further I/O's are redirected to only a few open zones till they
are full.
This patch modifies the random zone index genration logic so that it is uniform
across all the open zones.
---
zbd.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/zbd.c b/zbd.c
index 04c68de..43f12b4 100644
--- a/zbd.c
+++ b/zbd.c
@@ -1184,11 +1184,12 @@ out:
return res;
}
-/* Anything goes as long as it is not a constant. */
+/* Return random zone index for one of the open zones. */
static uint32_t pick_random_zone_idx(const struct fio_file *f,
const struct io_u *io_u)
{
- return io_u->offset * f->zbd_info->num_open_zones / f->real_file_size;
+ return (io_u->offset - f->file_offset) * f->zbd_info->num_open_zones /
+ f->io_size;
}
/*
--
1.8.3.1
