K 10
svn:author
V 3
mav
K 8
svn:date
V 27
2015-03-14T21:15:45.487338Z
K 7
svn:log
V 462
Give block I/O interface multiple (8) execution threads.

On parallel random I/O this allows better utilize wide storage pools.
To not confuse prefetcher on linear I/O, consecutive requests are executed
sequentially, following the same logic as was earlier implemented in CTL.

Benchmarks of virtual AHCI disk, backed by ZVOL on RAID10 pool of 4 HDDs,
show ~3.5 times random read performance improvements, while no degradation
on linear I/O.

MFC after:	2 weeks

END