インテル® VTune™ Amplifier 2018 ヘルプ
Serial Time is the time spent by the application outside any OpenMP region in the master thread during collection. It directly impacts application Collection Time and scaling. High values signal a performance problem to be solved via code parallelization or algorithm tuning.
Serial Time of your application is high. It directly impacts application Elapsed Time and scalability. Explore options for parallelization, algorithm or microarchitecture tuning of the serial part of the application.