Ticket spinlocks

Ticket spinlocks perform terribly for uncontested and highly contested cases. Test cases on
LKML do not show any of this (a very trivial test case was done that does not show lock *and*
unlock cost).

Here are relevant numbers on 16-core (8x2) AMD64 machine:
Highly contested, MCS has 30724 a/s (average) and ticket locks have 6315 a/s (average). In the
uncontested case, MCS has 836744 a/s (average) and ticket locks have 688817 a/s (average).
Both implement FIFO fairness, anyways, so I do not expect relevance WRT "thundering herd"
problem.

MCS will perform better than the Anderson locks implemented under the name of "Fairlocks" and
"J-Locks" for Linux, also (I assume these are the NUMA-aware locking primitives you are
talking about?).

There are other implementations that perform better than both of these. Ticket lock with
proportional back-off helps alleviate performance issues in the highly contested case.