From owner-freebsd-net Tue Dec 15 08:30:45 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id IAA15316 for freebsd-net-outgoing; Tue, 15 Dec 1998 08:30:45 -0800 (PST) (envelope-from owner-freebsd-net@FreeBSD.ORG) Received: from alive.znep.com (sense-sea-MegaSub-1-222.oz.net [216.39.144.222]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id IAA15311 for ; Tue, 15 Dec 1998 08:30:44 -0800 (PST) (envelope-from marcs@znep.com) Received: from localhost (marcs@localhost) by alive.znep.com (8.9.1/8.9.1) with ESMTP id IAA05778; Tue, 15 Dec 1998 08:30:13 -0800 (PST) (envelope-from marcs@znep.com) Date: Tue, 15 Dec 1998 08:30:12 -0800 (PST) From: Marc Slemko To: Michael Robinson cc: fenner@parc.xerox.com, freebsd-net@FreeBSD.ORG Subject: Re: MLEN < write length < MINCLSIZE "bug" In-Reply-To: <199812151555.PAA07456@netrinsics.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org (-stable removed from the cc list, since this isn't particular to stable in any way) On Tue, 15 Dec 1998, Michael Robinson wrote: > Bill Fenner writes: > >You misunderstand. The fix is to accumulate mbufs in a chain until either > >a) The protocol gets all of the data that it wanted, or > >b) All of the data that the user has provided has been copied into mbufs. > > > >(b) is what sosend() used to do. The URL referenced (the one with > >"vanj88" in it) describes why sosend() was changed to use only a single > >mbuf at a time, but this performance problem was not envisioned at > >the time. > > Ok, I misunderstood. But I still disagree it's a bug. Or, more precisely, > it would be a bug if the socket API and the TCP protocol were seen as one > inseparable entity, which is not the case. No, it really is a bug. It is inherently broken to write multiple packets for one write() when the size of the write is far less than the MTU (well, the "effective MTU") unless you have extreme extenuating circumstances. It may not be a bug covered by any spec, but for people trying to write useful network apps it shoots them in the head. It is still a bug. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message