From owner-svn-src-head@FreeBSD.ORG Wed Jun 26 09:13:40 2013 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id F3F8E54A; Wed, 26 Jun 2013 09:13:39 +0000 (UTC) (envelope-from marck@rinet.ru) Received: from woozle.rinet.ru (woozle.rinet.ru [195.54.192.68]) by mx1.freebsd.org (Postfix) with ESMTP id 5A3D418FD; Wed, 26 Jun 2013 09:13:38 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by woozle.rinet.ru (8.14.5/8.14.5) with ESMTP id r5Q9DbDP051646; Wed, 26 Jun 2013 13:13:37 +0400 (MSK) (envelope-from marck@rinet.ru) Date: Wed, 26 Jun 2013 13:13:37 +0400 (MSK) From: Dmitry Morozovsky To: Gleb Smirnoff Subject: Re: svn commit: r252032 - head/sys/amd64/include In-Reply-To: <20130626091055.GU1214@FreeBSD.org> Message-ID: References: <20130622124832.S2347@besplex.bde.org> <20130622174921.I3112@besplex.bde.org> <20130623073343.GY91021@kib.kiev.ua> <20130623181458.J2256@besplex.bde.org> <20130624170849.GH91021@kib.kiev.ua> <20130625102023.K899@besplex.bde.org> <20130625062039.GJ91021@kib.kiev.ua> <20130625190352.P986@besplex.bde.org> <20130625205826.GM91021@kib.kiev.ua> <20130626092955.B891@besplex.bde.org> <20130626091055.GU1214@FreeBSD.org> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) X-NCC-RegID: ru.rinet X-OpenPGP-Key-ID: 6B691B03 MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (woozle.rinet.ru [0.0.0.0]); Wed, 26 Jun 2013 13:13:37 +0400 (MSK) Cc: Konstantin Belousov , svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Bruce Evans X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jun 2013 09:13:40 -0000 On Wed, 26 Jun 2013, Gleb Smirnoff wrote: > On Wed, Jun 26, 2013 at 11:42:39AM +1000, Bruce Evans wrote: > B> > Anyway, as Gleb said, there is no point in > B> > optimizing the i386 kernel. > B> > B> I said that there is every point in optimizing the i386 kernel. This > B> applies even more to other 32-bit arches. Some CPUs are much slower > B> than modern x86's. They shouldn't be slowed down more by inefficient > B> KPIs. > > I didn't mean that i386 arch is a relic and should be ignored at all. > > What I actually meant, is that the problem of performance drop due to > cache poisoning and loss of statistics with simple "+=" operation can > be observed only at extremely high event rates, with multiple processors > involved. > > The counter(9) is solution for these conditions. Thus we are interested > in optimising amd64, not i386. The latter isn't affected neither positively > nor negatively with these changes, just because last i386 CPUs can't reach > the event rates where need for counter(9) arises. Yes, you can tweak > implementation and obtain better results with microbenchmarks, but I bet > that any change in counter(9) implementation won't affect packet forwarding > rate on any i386. What we claim for i386 (and all other arches) that > counter(9) is lossless, and that's all. > > I second to Konstantin, that we don't have objections in any changes to > i386 part of counter, including a daemon, but the changes shouldn't affect > amd64. Ah, apparently this mostly answers the question I've just asked ;) -- Sincerely, D.Marck [DM5020, MCK-RIPE, DM3-RIPN] [ FreeBSD committer: marck@FreeBSD.org ] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------