From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: [PATCH net-next] tcp: add tcpi_segs_in and tcpi_segs_out to tcp_info Date: Wed, 20 May 2015 17:06:37 -0700 Message-ID: <555D218D.50509@hp.com> References: <1430260098-14127-1-git-send-email-edumazet@google.com> <20150512130855.GA29412@localhost.localdomain> <1431462713.566.95.camel@edumazet-glaptop2.roam.corp.google.com> <1432164941.4060.57.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , "David S. Miller" , netdev , Yuchung Cheng , Matt Mathis , Craig Gallek , Martin Lau , Chris Rapier To: Eric Dumazet , Marcelo Ricardo Leitner Return-path: Received: from g9t5008.houston.hp.com ([15.240.92.66]:49221 "EHLO g9t5008.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751962AbbEUAGs (ORCPT ); Wed, 20 May 2015 20:06:48 -0400 In-Reply-To: <1432164941.4060.57.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On 05/20/2015 04:35 PM, Eric Dumazet wrote: > From: Marcelo Ricardo Leitner > > This patch tracks the total number of inbound and outbound segments on a > TCP socket. One may use this number to have an idea on connection > quality when compared against the retransmissions. > > RFC4898 named these : tcpEStatsPerfSegsIn and tcpEStatsPerfSegsOut > > These are a 32bit field each and can be fetched both from TCP_INFO > getsockopt() if one has a handle on a TCP socket, or from inet_diag > netlink facility (iproute2/ss patch will follow) I suppose it is far-fetched, but is it a concern that at 100 Gbit/s and 1500 byte MTU the 32 bit segment counter would wrap in something like 500 seconds and change? rick jones