tree 51526a90f372dca0811c93e0311c5b5301d094be
parent 0048b4837affd153897ed1222283492070027aa9
author Jeff Moyer <jmoyer@redhat.com> 1439492276 -0400
committer Jens Axboe <axboe@fb.com> 1439929273 -0700

Revert "block: remove artifical max_hw_sectors cap"

This reverts commit 34b48db66e08ca1c1bc07cf305d672ac940268dc.
That commit caused performance regressions for streaming I/O
workloads on a number of different storage devices, from
SATA disks to external RAID arrays.  It also managed to
trip up some buggy firmware in at least one drive, causing
data corruption.

The next patch will bump the default max_sectors_kb value to
1280, which will accommodate a 10-data-disk stripe write
with chunk size 128k.  In the testing I've done using iozone,
fio, and aio-stress, a value of 1280 does not show a big
performance difference from 512.  This will hopefully still
help the software RAID setup that Christoph saw the original
performance gains with while still not regressing other
storage configurations.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>