taglinefilesource code
when56include/linux/skbuff.hunsigned long  when;      /* used to compute rtt's      */
when694net/core/skbuff.cn->when=skb->when;
when355net/ipv4/ip_output.cskb->when = jiffies;
when658net/ipv4/ip_output.cskb->when=jiffies;
when824net/ipv4/ip_output.cskb->when = jiffies;
when91net/ipv4/tcp_input.cm = jiffies - oskb->when;  /* RTT */
when1047net/ipv4/tcp_input.c(sk->send_head->when + sk->rto < jiffies))) 
when1049net/ipv4/tcp_input.cif(sk->send_head->when + sk->rto < jiffies)
when332net/ipv4/tcp_output.cskb->when = jiffies;
when29net/ipv4/tcp_timer.cvoid tcp_reset_xmit_timer(struct sock *sk, int why, unsigned long when)
when33net/ipv4/tcp_timer.cif((long)when < 0)
when35net/ipv4/tcp_timer.cwhen=3;
when38net/ipv4/tcp_timer.csk->retransmit_timer.expires=jiffies+when;
when198net/ipv4/tcp_timer.cif (jiffies < skb->when + sk->rto) 
when202net/ipv4/tcp_timer.ctcp_reset_xmit_timer (sk, TIME_WRITE, skb->when + sk->rto - jiffies);