rack_grab_rtt
srtt = rack_grab_rtt(tp, rack);
thresh = rack_calc_thresh_rack(rack, rack_grab_rtt(rack->rc_tp, rack), cts, __LINE__, 1);
rack_grab_rtt(struct tcpcb *tp, struct tcp_rack *rack);
srtt = rack_grab_rtt(tp, rack);
srtt = rack_grab_rtt(tp, rack);
(srtt < rack_grab_rtt(tp, rack))) {
srtt = rack_grab_rtt(tp, rack);
thresh = rack_calc_thresh_rack(rack, rack_grab_rtt(tp, rack), cts, __LINE__, 0);
thresh = rack_calc_thresh_rack(rack, rack_grab_rtt(tp, rack), cts, __LINE__, 0);