My current research involves locking primitives profiling (e.g. mutex, conditional var, etc).
I search the internet almost everyday for profiling tools and papers, but sometimes I forget to search my own machine.
Today I "discovered" that my everyday macbook can lock profiling with one simple command:
tralamazza$ sudo plockstat -n 5 -A -s 8 -e 10 -p <app pid here>
This simple tool plockstat is implemented using DTrace (long live Leopard) and it can display lock contention/wait time along with backtrace for any application.
Even better you can instruct plockstat to show the generated DTrace script so you can customize it.
Not bad at all.