Benchmarking a 4way

I have a 4way xeon with 4 gigs of ram, and 2meg l2 cache on each cpu.
So far I have run a few benchmarks comparing the three primary BSDs.
http://nikto.linbsd.org/obsd nbsd and fbsd
The results are all run together.
I am cleaning them up for proper display in charts.
However what I am looking for is any suggestions for
really testing the MP aspects of the OS, and something that would
really thrash the locking in the kernel.

Thanks in advance.

-Ober