From owner-freebsd-arch@FreeBSD.ORG Wed Dec 22 20:57:32 2010 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 731651065675 for ; Wed, 22 Dec 2010 20:57:32 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 5075C8FC16 for ; Wed, 22 Dec 2010 20:57:32 +0000 (UTC) Received: from fledge.watson.org (fledge.watson.org [65.122.17.41]) by cyrus.watson.org (Postfix) with ESMTPS id CC0AC46B49; Wed, 22 Dec 2010 15:57:31 -0500 (EST) Date: Wed, 22 Dec 2010 20:57:31 +0000 (GMT) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Mike Karels In-Reply-To: <201012221745.oBMHj7Wg039593@mail.karels.net> Message-ID: References: <201012221745.oBMHj7Wg039593@mail.karels.net> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-arch@freebsd.org Subject: Re: Schedule for releases X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Dec 2010 20:57:32 -0000 On Wed, 22 Dec 2010, Mike Karels wrote: > - We sometimes back-port other changes, such as TCP locking fixes that help > performance. Considering some such things for MFC would be desirable. Just to comment on the specifics of this one: over the cource of 6.x, 7.x, and 8.x, I non-trivially improved locking in the TCP/UDP code. Some of those changes could be backported -- others couldn't be. Part of the reason I didn't merge some changes was our increasing attempt to provide stable KPIs and KBIs for kernel modules, especially as TCP offload support in device drivers became a reality. We're now going to hit the same issue in 9.x: I'm about to commit significant network stack locking and work distribution changes to improve TCP and UDP scalability, leading to multiplied performance on parallel systems. As of the interpretation of KPI/KBI compatibility we have today, these cannot be MFC'd to 8.x. I think there's a motivation to revisit our thinking on KPI/KBI so that we can merge them to 8.x in the future; I'll say more about this on the net@ mailing list in a month or so once the changes are in 9.x and have shaken out a bit. Robert