tree 9a6cd957d0ca463247d3e57438cfec5e2702a661
parent bf2b79e7c4b312aa6e1c661fb27e0dc4dd42f2c2
author Paolo Valente <paolo.valente@linaro.org> 1492014199 +0200
committer Jens Axboe <axboe@fb.com> 1492612226 -0600

block, bfq: boost the throughput with random I/O on NCQ-capable HDDs

This patch is basically the counterpart, for NCQ-capable rotational
devices, of the previous patch. Exactly as the previous patch does on
flash-based devices and for any workload, this patch disables device
idling on rotational devices, but only for random I/O. In fact, only
with these queues disabling idling boosts the throughput on
NCQ-capable rotational devices. To not break service guarantees,
idling is disabled for NCQ-enabled rotational devices only when the
same symmetry conditions considered in the previous patches hold.

Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>