iftcpaf <ifname> [tcpaf (2~127)]

[root@sylixos:/root]# help iftcpaf        
Set/Get TCP ACK Frequency for net interface
eg. iftcpaf lo0    (get 'lo0' TCP ACK Frequency setting)
    iftcpaf en1 4  (set 'en1' TCP ACK Frequency to 4)
iftcpaf [ifname] [tcpaf (1~127)]
[root@sylixos:/root]# 

[root@sylixos:/root]# iftcpaf lo0
TCP ACK Frequency: 2

[root@sylixos:/root]# iftcpaf en1 4
TCP ACK Frequency: 4