Profiling my codes, I observed some curiously large overhead and spin time, which covered almost 100% of the CPU usage bar. I use Vtune 2013 and 2015.
In the summary page, it shows : CPU time: 420.6s, Overhead time: 0.3s , Spin time:284.125, concurrency ideal.
I know that Spin time means that one thread is blocking to wait the resource free from another thread, it consumes high CPU time. However I did not use any lock. Can you please clarify this issue?