From owner-freebsd-current@FreeBSD.ORG Tue Sep 14 09:33:23 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 53AA6106566C; Tue, 14 Sep 2010 09:33:23 +0000 (UTC) (envelope-from fabien.thomas@netasq.com) Received: from work.netasq.com (mars.netasq.com [91.212.116.3]) by mx1.freebsd.org (Postfix) with ESMTP id 72DA38FC12; Tue, 14 Sep 2010 09:33:21 +0000 (UTC) Received: from [10.20.1.1] (unknown [10.2.27.254]) by work.netasq.com (Postfix) with ESMTPSA id 98AA2740015; Tue, 14 Sep 2010 11:17:47 +0200 (CEST) Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: text/plain; charset=us-ascii From: Fabien Thomas In-Reply-To: <4C8E0C1E.2020707@networx.ch> Date: Tue, 14 Sep 2010 11:18:14 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <4C8E0C1E.2020707@networx.ch> To: Andre Oppermann X-Mailer: Apple Mail (2.1081) Cc: freebsd-net@freebsd.org, freebsd-current@freebsd.org Subject: Re: TCP loopback socket fusing X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Sep 2010 09:33:23 -0000 Great, This will maybe kill the long time debate about "my loopback is slow vs = linux" To have the best of both world what about a socket option to = enable/disable fusing: can be useful when you need to see some connection "packetized". Fabien On 13 sept. 2010, at 13:33, Andre Oppermann wrote: > When a TCP connection via loopback back to localhost is made the whole > send, segmentation and receive path (with larger packets though) is = still > executed. This has some considerable overhead. >=20 > To short-circuit the send and receive sockets on localhost TCP = connections > I've made a proof-of-concept patch that directly places the data in = the > other side's socket buffer without doing any packetization and other = protocol > overhead (like UNIX domain sockets). The connections setup (SYN, = SYN-ACK, > ACK) and shutdown are still handled by normal TCP segments via = loopback so > that firewalling stills works. The actual payload data during the = session > won't be seen and the sequence numbers don't move other than for SYN = and FIN. > The sequence are remain valid though. Obviously tcpdump won't see any = data > transfers either if the connection has fused sockets. >=20 > Preliminary testing (with WITNESS and INVARIANTS enabled) has shown = stable > operation and a rough doubling of the throughput on loopback = connections. > I've tested most socket teardown cases and it behaves fine. I'm not = entirely > sure I've got all possible path's but the way it is integrated should = properly > defuse the sockets in all situations. >=20 > Testers and feedback wanted: >=20 > http://people.freebsd.org/~andre/tcp_loopfuse-20100913.diff >=20 > --=20 > Andre >=20 > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"