CAM. This can significantly improve performance particularly for SSDs
which don't suffer from seek latencies.
The sysctl / tunable kern.cam.sort_io_queues provides the systems default
setting where:-
0 = queued BIOs are NOT sorted
1 = queued BIOs are sorted (default)
Each device gets its own sysctl kern.cam.<type>.<id>.sort_io_queue
Valid values are:-
-1 = use system default (default)
0 = queued BIOs are NOT sorted
1 = queued BIOs are sorted
Note: Additional patch will look to add automatic use of none sorted queues
for none rotating media e.g. SSD's
Reviewed by: scottl
Approved by: pjd (mentor)
MFC after: 2 weeks
fc36a232b9