Your comment reflects a couple of fundamental misunderstandings about both SMP architectures and the locking primitives in the kernel; if you would like technical details that guided some of the implementation decisions in illumos, see the paper that I wrote with Jeff Bonwick in 2008.[0] There are several pieces of advice in there that particularly apply to your comment, first among them: "Intuition is frequently wrong -- be data intensive."
[0] https://queue.acm.org/detail.cfm?id=1454462