---------- Forwarded message --------- 发件人: yuanli fu <fuyuanli0...@gmail.com> Date: 2024年2月29日周四 16:27 Subject: Re: [PATCH] tcp: Add skb addr and sock addr to arguments of tracepoint tcp_probe. To: Jason Xing <kerneljasonx...@gmail.com>
Jason Xing <kerneljasonx...@gmail.com> 于2024年2月29日周四 15:30写道: > > On Thu, Feb 29, 2024 at 1:33 PM fuyuanli <fuyua...@didiglobal.com> wrote: > > > > It is useful to expose skb addr and sock addr to user in tracepoint > > tcp_probe, so that we can get more information while monitoring > > receiving of tcp data, by ebpf or other ways. > > > > For example, we need to identify a packet by seq and end_seq when > > calculate transmit latency between lay 2 and lay 4 by ebpf, but which is > > not available in tcp_probe, so we can only use kprobe hooking > > tcp_rcv_esatblised to get them. But we can use tcp_probe directly if skb > > addr and sock addr are available, which is more efficient. > > > > Signed-off-by: fuyuanli <fuyua...@didiglobal.com> > > Please target 'net-next' in the title of your v2 patch. Got it, thanks. > > > --- > > include/trace/events/tcp.h | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h > > index 7b1ddffa3dfc..096c15f64b92 100644 > > --- a/include/trace/events/tcp.h > > +++ b/include/trace/events/tcp.h > > @@ -258,6 +258,8 @@ TRACE_EVENT(tcp_probe, > > __field(__u32, srtt) > > __field(__u32, rcv_wnd) > > __field(__u64, sock_cookie) > > + __field(const void *, skbaddr) > > + __field(const void *, skaddr) > > ), > > > > TP_fast_assign( > > @@ -285,6 +287,9 @@ TRACE_EVENT(tcp_probe, > > __entry->ssthresh = tcp_current_ssthresh(sk); > > __entry->srtt = tp->srtt_us >> 3; > > __entry->sock_cookie = sock_gen_cookie(sk); > > + > > + __entry->skbaddr = skb; > > + __entry->skaddr = sk; > > ), > > > > TP_printk("family=%s src=%pISpc dest=%pISpc mark=%#x data_len=%d > > snd_nxt=%#x snd_una=%#x snd_cwnd=%u ssthresh=%u snd_wnd=%u srtt=%u > > rcv_wnd=%u sock_cookie=%llx", > > If they are useful, at least you should printk those two addresses > like what trace_kfree_skb() does. > Got it, I will add to printk > May I ask how it could be useful if there is no more function printing > such information in the receive path? We can get seq and end_seq by skbaddr in netif_receive_skb, so latency between l2->l4 can be calculated. > > Thanks, > Jason > > -- > > 2.17.1 > > > > > thanks fuyuanli