taglinefilesource code
when48include/linux/skbuff.hvolatile unsigned long  when;      /* used to compute rtt's      */
when668net/core/skbuff.cn->when=skb->when;
when354net/ipv4/ip_output.cskb->when = jiffies;
when656net/ipv4/ip_output.cskb->when=jiffies;
when822net/ipv4/ip_output.cskb->when = jiffies;
when651net/ipv4/tcp.cskb->when = jiffies;
when796net/ipv4/tcp.cstatic void reset_xmit_timer(struct sock *sk, int why, unsigned long when)
when800net/ipv4/tcp.cif((int)when < 0)
when802net/ipv4/tcp.cwhen=3;
when805net/ipv4/tcp.csk->retransmit_timer.expires=jiffies+when;
when1006net/ipv4/tcp.cif (jiffies < skb->when + sk->rto) 
when1008net/ipv4/tcp.creset_xmit_timer (sk, TIME_WRITE, skb->when + sk->rto - jiffies);
when3703net/ipv4/tcp.cm = jiffies - oskb->when;  /* RTT */
when3958net/ipv4/tcp.c(sk->send_head->when + sk->rto < jiffies))) 
when3960net/ipv4/tcp.cif(sk->send_head->when + sk->rto < jiffies)