Intel® VTune™ Amplifier
For a custom event-based sampling data collection, set up the Sample After Value (SAV) that is a frequency with which the Intel® VTune™ Amplifier interrupts the processor to collect a sample during hardware event-based data collection. SAV is measured as the number of events it takes to trigger a sample collection.
A Sample After Value that is too small causes the sampling interrupts to occur too frequently, which can lead to performance degradation and system instability. VTune Amplifier enforces a floor value to prevent such a behavior. The recommended value is 1000 samples per second per processor.
VTune Amplifier sets the Sample After value for hardware events automatically. For predefined hardware-level analysis types, the Sample After value is displayed in the Analysis Type window. You cannot edit the Sample After value provided in the table for each event. But during the data collection the VTune Amplifier may adjust it by a multiplier. The multiplier depends on the sampling interval value specified in the Analysis Type tab.
To edit the default Sample After value, you need to create a custom hardware event-based analysis type (based on an existing type), add events, if required, and edit a Sample After value in the events table by selecting it as follows: