Dell PowerEdge FN I/O Module Configuration Guide 9.10(0.0)

Therefore, the sFlow agent uses sub-sampling to create multiple sampling rates per port-pipe. To achieve different sampling rates for different ports in a port-pipe, the sFlow agent takes the lowest numerical value of the sampling rate of all the ports within the port-pipe and configures all the ports to this value. The sFlow agent is then able to skip samples on ports where you require a larger sampling rate value.

Sampling rates are configurable in powers of two. This configuration allows the smallest sampling rate possible on the hardware and also allows all other sampling rates to be available through sub-sampling.