From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next] tcp: expose sk_state in tcp_retransmit_skb tracepoint Date: Sun, 23 Sep 2018 14:42:30 -0700 Message-ID: <375c389d-f391-5b72-bc52-9a82d61c6bd7@gmail.com> References: <1537732141-22468-1-git-send-email-laoar.shao@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Yafang Shao , edumazet@google.com, davem@davemloft.net Return-path: In-Reply-To: <1537732141-22468-1-git-send-email-laoar.shao@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 09/23/2018 12:49 PM, Yafang Shao wrote: > With sk_state, we can know whether this connection is in SYN_SENT state > or ESTBLISHED state. > The reason to distinguish between these two scenario is that the > retransmission in ESTABLISHED state always mean network congestion while > in SYN_SENT state it always mean server issue, i.e. the syn packet is > dropped due to syn backlog queue full. You mean, a packet drop on the remote peer ? It could also be a packet drop in the network. Your patch is good, but changelog is quite misleading.