Hello,
1. Traffic suppression only takes effect for unknown unicast packets and can be counted based on the rate of unknown packets. Storm suppression does not distinguish known and unknown unicast packets, so the device counts the total rate of unknown and known unicast packets. When the storm control action is “block”, the device blocks only unknown unicast packets. The packet rate is calculated based on the ratio of the packet rate and the port bandwidth.
2. If "unicast-suppression90" is configured on the interface, when the rate of unknown unicast packets arrives 90% of interface bandwidth, the device will drop the exceeding unknown unicast packets.
3. Traffic suppression and storm suppression on an interface takes effect only for incoming packets on that interface. Traffic suppression is irrelevant to upstream and downstream traffic.
unicast-suppression:
https://support.huawei.com/hedex/pages/EDOC1100064949DEI0130R/04/EDOC1100064949DEI0130R/04/resources/dc/unicast-suppression.html?ft=0&fe=10&hib=6.15.5.16&id=unicast-suppression&text=unicast-suppression (interface view)&docid=EDOC1100064949

Storm-control:
https://support.huawei.com/hedex/pages/EDOC1100064949DEI0130R/04/EDOC1100064949DEI0130R/04/resources/dc/storm-control.html?ft=0&fe=10&hib=6.15.5.11&id=storm-control&text=storm-control&docid=EDOC1100064949

I hope this helps.