By lowering the sampling rate of NetStream, you can reduce the impact on the forwarding performance of the FW. However, raising the sampling rate improves the statistical accuracy.
If the interface is configured with a sampling rate, the passing traffic flows are sampled at the rate. If not, the sampling rate is 1:1, that is, all packets along the passing traffic flows are sampled.
system-view
interface interface-type interface-number
{ ip | ipv6 } netstream sampler fix-packets packet-interval inbound
If both IPv4 and IPv6 data flows are sampled on an interface, the sampling intervals must be the same.