I know I am missing something, but passing -F 49 to perf will tell the kernel to adjust the sampling interval dynamically so approximately 49 events/s are recor

I know I am missing something, but passing -F 49 to perf will tell the kernel to adjust the sampling interval dynamically so approximately 49 events/s are recorded, right? But then how does it make sense to plot the number of events per second in the overview? Or what exactly is being plotted in the overview? Edit: Perhaps it is simply that idle events are discarded and multiple CPUs allow more than one event in the period?