Blogbench RAID benchmarks

[Samuel J. Greear]

>    I'm not sure where the concurrency is breaking down on the RAID subsystem,
>    it could be due to that particular driver still being under the big
>    giant lock (the AHCI and SILI drivers don't use the bgl, but arcmsr
>    driver probably still does).
>

arcmsr uses lockmgr and is not under the mplock at all. Which is not
to say it isn't still serializing internally somewhere, but it should
not be any different than FreeBSD in this regard.

Sam