taglinefilesource code
ssthresh574net/inet/af_inet.csk->ssthresh = 0;
ssthresh116net/inet/sock.hvolatile unsigned short  ssthresh;
ssthresh240net/inet/tcp.csk->ssthresh = sk->cong_window >> 1; /* remember window where we lost */
ssthresh1962net/inet/tcp.cnewsk->ssthresh = 0;
ssthresh2606net/inet/tcp.cif (sk->cong_window < sk->ssthresh)