-profile and threaded code

[BCS]

I have a program that runs an "easily" parallelizable loop. When I run it 
as a single thread it only takes about 10% longer than 2 threads (on a dual-core). 
I'm trying to track down the lossed time and am wondering if turning on -profile 
is even worth looking at. The concern is that it might not be thread safe 
or might just skew the result so much as to be useless.