Suppose you have a machine with 2GHz CPU. By setting the SAV=2000000 for CPU clockticks event in the EBS analysis of VTune or Lightweight Hotspot analysis of VTune Amplifier XE, you get 1 sample per ms. This is statistically reasonable sampling rate for most cases. Playing with the SAV towards decrease allows to increase the sampling frequency. But be careful setting too low SAV - the system may hang in oft-recurring hardware interruption handling.