llvm dev - Jun 2012 - [LLVMdev] no differnce in the execution time between seq. and parallel programs

Hi all
please can any one help me to find the reason??

i am using LLVM to execute two programs both of them was exactly  
similar but the difference was the first one is a sequential program  
has three functions. In the second program i am trying to execute it  
by giving each function to thread (three thread work in parallel way)  
,but when i am trying to calculate the execution time i found the  
execution time for parallel one larger than sequential one ????

note
I execute both of these program in gcc compiler and i found there is a  
difference in the execution time between these programs.The parallel  
one was faster than the sequential one.

i will be thankful if any one can help me
Regards
esraa