HHF qdisc parameters:
- limit: max number of packets in qdisc (default 1000)
- quantum: max deficit per RR round (default 1 MTU)
- hh_limit: max number of HHs to keep states (default 2048)
- reset_timeout: time to reset HHF counters (default 40ms)
- admit_bytes: counter thresh to classify as HH (default 128KB)
- evict_timeout: threshold to evict idle HHs (default 1s)
- non_hh_weight: DRR weight for mice (default 2)