From owner-svn-src-all@FreeBSD.ORG Fri Dec 20 08:44:37 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id A024A7F2; Fri, 20 Dec 2013 08:44:37 +0000 (UTC) Received: from cell.glebius.int.ru (glebius.int.ru [81.19.69.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 1D1741CBB; Fri, 20 Dec 2013 08:44:35 +0000 (UTC) Received: from cell.glebius.int.ru (localhost [127.0.0.1]) by cell.glebius.int.ru (8.14.7/8.14.7) with ESMTP id rBK8iJGq075862 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 20 Dec 2013 12:44:19 +0400 (MSK) (envelope-from glebius@FreeBSD.org) Received: (from glebius@localhost) by cell.glebius.int.ru (8.14.7/8.14.7/Submit) id rBK8iJnG075861; Fri, 20 Dec 2013 12:44:19 +0400 (MSK) (envelope-from glebius@FreeBSD.org) X-Authentication-Warning: cell.glebius.int.ru: glebius set sender to glebius@FreeBSD.org using -f Date: Fri, 20 Dec 2013 12:44:19 +0400 From: Gleb Smirnoff To: Adrian Chadd Subject: Re: svn commit: r259642 - head/sys/netinet Message-ID: <20131220084419.GK71033@FreeBSD.org> References: <201312200741.rBK7f3tL038123@svn.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201312200741.rBK7f3tL038123@svn.freebsd.org> User-Agent: Mutt/1.5.22 (2013-10-16) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Dec 2013 08:44:37 -0000 On Fri, Dec 20, 2013 at 07:41:03AM +0000, Adrian Chadd wrote: A> Author: adrian A> Date: Fri Dec 20 07:41:03 2013 A> New Revision: 259642 A> URL: http://svnweb.freebsd.org/changeset/base/259642 A> A> Log: A> Disable the now unpredicably bogus check for whether we have A> eneough queue space before queuing a bunch of IP fragments. A> A> As the comment in the committed change says, in the post-if_transmit(), A> post-SMP, post-preemption world, there's just too much overlapping A> concurrent code paths and different approaches to driver transmit A> queue management to have this code even remotely be effective. A> A> The only specific place it could be useful is if ALTQ is enabled A> but again it doesn't at all promise that all the fragments will be A> transmitted anyway. A> A> The main reason for committing this change is to disable a parallel A> place where the drops counter is incremented. This is a side effect A> of an upcoming change to ixgbe/cxgbe to handle the queue drops A> counter slightly better. I didn't get to review of actual patch, but IMO it would be better just to remove the code, not ifdef 0 it. The code ifdefed has zero probability to be enabled in its current form. If we ever fix it, code would look very different. No reason to do followup commit, that was just me muttering. -- Totus tuus, Glebius.