From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-x234.google.com (mail-ig0-x234.google.com [IPv6:2607:f8b0:4001:c05::234]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 3647821F22D for ; Wed, 22 Apr 2015 16:08:35 -0700 (PDT) Received: by igblo3 with SMTP id lo3so9889930igb.0 for ; Wed, 22 Apr 2015 16:08:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:subject:from:to:cc:date:in-reply-to:references :content-type:mime-version:content-transfer-encoding; bh=cm+w8otRewlwJDLLb7QoaVYu7jU/D+JBDtonRnAtbmg=; b=uh1w0fY2sPMM4QhPHpV8Z4d+n/WcubWvxvKq27O3slOC7D1DdJ+e7JSw/ZD/lYQpL5 B/UhwNX6/9mv4f9NYGB3TY8IG5gODcuVGkA9CwdxHDXBqupjV2535eZkS38dPv8Fl3+Y Il28Lq/IWxgEx6MzmMBPbNP+REItlJ2xEXsvGOWcfSTWhjJ/+nrstkm+wW/vDkTU0trr rMdBwinK569r+ziVs/BlEBwET4jjo7x3wvF8LZD8f0ev31j/BnR2Dh5e0G8zDw5Q1ymz y2YEm8+QorrzRFp0teAzVP2g+5MjGxPFnN9oFCVwiwObTX1YzTa4C1CkBJhSeghzYZOn pn0A== X-Received: by 10.42.236.132 with SMTP id kk4mr496825icb.46.1429744115246; Wed, 22 Apr 2015 16:08:35 -0700 (PDT) Received: from [172.26.55.207] ([172.26.55.207]) by mx.google.com with ESMTPSA id g2sm11088131igt.8.2015.04.22.16.08.34 (version=TLSv1.2 cipher=AES128-GCM-SHA256 bits=128/128); Wed, 22 Apr 2015 16:08:34 -0700 (PDT) Message-ID: <1429744113.18561.169.camel@edumazet-glaptop2.roam.corp.google.com> From: Eric Dumazet To: Simon Barber Date: Wed, 22 Apr 2015 16:08:33 -0700 In-Reply-To: <14ce337d3c8.27f7.e972a4f4d859b00521b2b659602cb2f9@superduper.net> References: <20150422191056.9C7AC406057@ip-64-139-1-69.sjc.megapath.net> <1429736552.18561.144.camel@edumazet-glaptop2.roam.corp.google.com> <55380D28.5080100@hp.com> <1429739215.18561.151.camel@edumazet-glaptop2.roam.corp.google.com> <14ce337d3c8.27f7.e972a4f4d859b00521b2b659602cb2f9@superduper.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Cc: Hal Murray , bloat Subject: Re: [Bloat] SO_SNDBUF and SO_RCVBUF X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Apr 2015 23:09:04 -0000 On Wed, 2015-04-22 at 15:20 -0700, Simon Barber wrote: > Wouldn't the LOWAT setting be much easier for applications to use if it was > set in estimated time (ie time it will take to deliver the data) rather > than bytes? Sure, but you have all the info to infer one from the other. Note also TCP stack has immediate notion of bytes, while adding time delays immediately impose a possibly expensive time acquisition in high precision. # git show c9bee3b7fdecb0c1d070c7b54113b3bdfb9a3d36 | diffstat -p1 -w70 Documentation/networking/ip-sysctl.txt | 13 +++++++++++++ include/linux/tcp.h | 1 + include/net/sock.h | 19 +++++++++++++------ include/net/tcp.h | 14 ++++++++++++++ include/uapi/linux/tcp.h | 1 + net/ipv4/sysctl_net_ipv4.c | 7 +++++++ net/ipv4/tcp.c | 7 +++++++ net/ipv4/tcp_ipv4.c | 1 + net/ipv4/tcp_output.c | 3 +++ net/ipv6/tcp_ipv6.c | 1 + 10 files changed, 61 insertions(+), 6 deletions(-) A time based implementation would be way more complex/expensive.