taglinefilesource code
when48include/linux/skbuff.hvolatile unsigned long  when;      /* used to compute rtt's      */
when614net/core/skbuff.cn->when=skb->when;
when2378net/ipv4/ip.cskb->when = jiffies;
when3212net/ipv4/ip.cskb->when=jiffies;
when3367net/ipv4/ip.cskb->when = jiffies;
when649net/ipv4/tcp.cskb->when = jiffies;
when779net/ipv4/tcp.cstatic void reset_xmit_timer(struct sock *sk, int why, unsigned long when)
when783net/ipv4/tcp.cif((int)when < 0)
when785net/ipv4/tcp.cwhen=3;
when788net/ipv4/tcp.csk->retransmit_timer.expires=jiffies+when;
when990net/ipv4/tcp.cif (jiffies < skb->when + sk->rto) 
when992net/ipv4/tcp.creset_xmit_timer (sk, TIME_WRITE, skb->when + sk->rto - jiffies);
when3638net/ipv4/tcp.cm = jiffies - oskb->when;  /* RTT */
when3893net/ipv4/tcp.c(sk->send_head->when + sk->rto < jiffies))) 
when3895net/ipv4/tcp.cif(sk->send_head->when + sk->rto < jiffies)