From c3fde1bd28f7c720d7bc587e85e54706df4f8163 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Fri, 29 Dec 2017 11:45:51 +0900 Subject: net: tcp: Add trace events for TCP congestion window tracing This adds an event to trace TCP stat variables with slightly intrusive trace-event. This uses ftrace/perf event log buffer to trace those state, no needs to prepare own ring-buffer, nor custom user apps. User can use ftrace to trace this event as below; # cd /sys/kernel/debug/tracing # echo 1 > events/tcp/tcp_probe/enable (run workloads) # cat trace Signed-off-by: Masami Hiramatsu Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 4d55c4b338ee..ff71b18d9682 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5299,6 +5299,9 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb, unsigned int len = skb->len; struct tcp_sock *tp = tcp_sk(sk); + /* TCP congestion window tracking */ + trace_tcp_probe(sk, skb); + tcp_mstamp_refresh(tp); if (unlikely(!sk->sk_rx_dst)) inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb); -- cgit v1.2.3