From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 18 Jan 2001 13:25:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 18 Jan 2001 13:25:07 -0500 Received: from palrel1.hp.com ([156.153.255.242]:34316 "HELO palrel1.hp.com") by vger.kernel.org with SMTP id ; Thu, 18 Jan 2001 13:24:55 -0500 Message-ID: <3A6734F0.E436B1A3@cup.hp.com> Date: Thu, 18 Jan 2001 10:24:48 -0800 From: Rick Jones Organization: the Unofficial HP X-Mailer: Mozilla 4.75 [en] (X11; U; HP-UX B.11.00 9000/785) X-Accept-Language: en MIME-Version: 1.0 To: Linux Kernel List Cc: Linus Torvalds Subject: Re: [Fwd: [Fwd: Is sendfile all that sexy? (fwd)]] In-Reply-To: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > > On Wed, 17 Jan 2001, Rick Jones wrote: > > > i'd heard interesting generalities but no specifics. for instance, > > when the send is small, does TCP wait exclusively for the app to > > flush, or is there an "if all else fails" sort of timer running? > > yes there is a per-socket timer for this. According to RFC 1122 a TCP > stack 'MUST NOT' buffer app-sent TCP data indefinitely if the PSH bit > cannot be explicitly set by a SEND operation. Was this a trick question? > :-) Nope, not a trick question. The nagle heuristic means that small sends will not wait indefinitely since sending the first small bit of data starts the retransmission timer as a course of normal processing. So, I am not in the habit of thinking about a "clear the buffer" timer being set when a small send takes place but no transmit happens. rick jones btw, as I'm currently on linux-kernel, no need to cc me :) -- ftp://ftp.cup.hp.com/dist/networking/misc/rachel/ these opinions are mine, all mine; HP might not want them anyway... :) feel free to email, OR post, but please do NOT do BOTH... my email address is raj in the cup.hp.com domain... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/