From owner-freebsd-net@FreeBSD.ORG Wed Jan 9 14:35:40 2013 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 5516F5CD for ; Wed, 9 Jan 2013 14:35:40 +0000 (UTC) (envelope-from barney_cordoba@yahoo.com) Received: from nm36-vm3.bullet.mail.ne1.yahoo.com (nm36-vm3.bullet.mail.ne1.yahoo.com [98.138.229.115]) by mx1.freebsd.org (Postfix) with ESMTP id 0A9AE291 for ; Wed, 9 Jan 2013 14:35:39 +0000 (UTC) Received: from [98.138.226.177] by nm36.bullet.mail.ne1.yahoo.com with NNFMP; 09 Jan 2013 14:35:33 -0000 Received: from [98.138.87.6] by tm12.bullet.mail.ne1.yahoo.com with NNFMP; 09 Jan 2013 14:35:33 -0000 Received: from [127.0.0.1] by omp1006.mail.ne1.yahoo.com with NNFMP; 09 Jan 2013 14:35:33 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 676871.70403.bm@omp1006.mail.ne1.yahoo.com Received: (qmail 11641 invoked by uid 60001); 9 Jan 2013 14:35:33 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1357742133; bh=l+Sg89LUUze5sbtxHi0XlpQlBLcaoMC7xffkaD1LgbM=; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:Message-ID:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type; b=2duJISat7W6xaUPpiwud/3nKtOb7jFIiqeUngsyHbtDWYb1xNBhuxdFxeKy1dqmUtzzLkXvpcJT9yWDuP1fuNmO/IZSmKfEm4/oIi15NzfYqhvQJ318IUnV1EI/m84y3whmVXYYlGdjeTzawNW0ijWkEDyRhqeTZ/WXmcGLCfms= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:Message-ID:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type; b=luZ5fT1lYMfgAn6TzfroybxwWEPd/GYnKfeUcSwFnpdjmY+PuaKH+RJ4vHhzyscyW5k2extJHX3TOMIMCmz5gE47yiM2NQCJe+YcWZnlt54mCaZxN/sSlwqMO3Pii0P3Q1WPH3cUXg1NZYMzS9GaMyaAdoap0VLs1uyuE3nFMPE=; X-YMail-OSG: iNYP7A0VM1ni51x6jZ.wesGV1T34KJaNCA1JqEOKbiEGOtg 2y12wKu7uQP2CmPK_3Kd6xO3b0rE91S7UUFtz7V_PO6Fz4v687VrWFS3bLgQ 5aPGrRcCECWubSg.jn4lpslh8kPEpznQNWpsBkdEA5fw233BgGncozNSoMjQ 5p5BeQEudCGnyOQvDlAio2Gkk6i_5wVd0Cvy5o_rrjBIELdBPNztQ4aPvtpG tv5iTErdgJ21.X8aNQQvbv6cF4KeFQ8pn0sTYt43uJXP0zSDC3yHcp23UqXk D4EBh8itnCO8aB2R4YCte_W7ofSsx9tEHYJKCW0QvERZzo4wULkS1cbB2T5k h1xYaGD6w42HLsFp7K8C_6LNCXXnyE5QxZBWphqBKeYIJKCITohy1jV1jXo0 cF9R1q.phkO7oLd3nItdfC6DHVhY4p6qHzAnsUzf3kFbtI4RBKzzoa0VJUgU GLfe4Udl.N.Hja50lcRlDsoyjCJHhZgwHvSKbtztQRwueQrzwSie.e_Iymq6 joER5IPTBGOx4LJCJPLhM116MrtzhAA-- Received: from [174.48.128.27] by web121601.mail.ne1.yahoo.com via HTTP; Wed, 09 Jan 2013 06:35:33 PST X-Rocket-MIMEInfo: 001.001, CgotLS0gT24gV2VkLCAxLzkvMTMsIEVyaWNoIERvbGxhbnNreSA8ZXJpY2hzZnJlZWJzZGxpc3RAYWxvZ3QuY29tPiB3cm90ZToKCj4gRnJvbTogRXJpY2ggRG9sbGFuc2t5IDxlcmljaHNmcmVlYnNkbGlzdEBhbG9ndC5jb20.Cj4gU3ViamVjdDogUmU6IFRvIFNNUCBvciBub3QgdG8gU01QCj4gVG86ICJCYXJuZXkgQ29yZG9iYSIgPGJhcm5leV9jb3Jkb2JhQHlhaG9vLmNvbT4KPiBDYzogIk1hcmsgQXRraW5zb24iIDxhdGtpbjkwMUBnbWFpbC5jb20.LCBmcmVlYnNkLW5ldEBmcmVlYnNkLm9yZywgamFjay4BMAEBAQE- X-Mailer: YahooMailClassic/15.1.2 YahooMailWebService/0.8.130.494 Message-ID: <1357742133.9692.YahooMailClassic@web121601.mail.ne1.yahoo.com> Date: Wed, 9 Jan 2013 06:35:33 -0800 (PST) From: Barney Cordoba Subject: Re: To SMP or not to SMP To: Erich Dollansky In-Reply-To: <20130109211439.5b590bf5@X220.ovitrap.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: freebsd-net@freebsd.org, jack.vogel@gmail.com, Mark Atkinson X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Jan 2013 14:35:40 -0000 --- On Wed, 1/9/13, Erich Dollansky wrote: > From: Erich Dollansky > Subject: Re: To SMP or not to SMP > To: "Barney Cordoba" > Cc: "Mark Atkinson" , freebsd-net@freebsd.org, jack.vogel@gmail.com > Date: Wednesday, January 9, 2013, 9:14 AM > Hi, > > On Wed, 9 Jan 2013 05:40:13 -0800 (PST) > Barney Cordoba > wrote: > > > --- On Wed, 1/9/13, Erich Dollansky > > wrote: > > > From: Erich Dollansky > > > Subject: Re: To SMP or not to SMP > > > To: "Mark Atkinson" > > > Cc: freebsd-net@freebsd.org > > > Date: Wednesday, January 9, 2013, 1:01 AM > > > Hi, > > > > > > On Tue, 08 Jan 2013 08:29:51 -0800 > > > Mark Atkinson > > > wrote: > > > > > > > -----BEGIN PGP SIGNED MESSAGE----- > > > > Hash: SHA1 > > > > > > > > On 01/07/2013 18:25, Barney Cordoba wrote: > > > > > I have a situation where I have to run > 9.1 on an > > > old single core > > > > > box. Does anyone have a handle on > whether it's > > > better to build a > > > > > non SMP kernel or to just use a standard > SMP build > > > with just the > > > > > one core? Thanks. > > > > > > > > You can build a SMP kernel, but you'll get > better > > > performance (in my > > > > experience) with SCHED_4BSD on single cpu > than with > > > ULE. > > > > > > > I would not say so. The machine behaves different > with the > > > two > > > schedulers. It depends mostly what you want to do > with the > > > machine. I > > > forgot which scheduler I finally left in the > single CPU > > > kernel. > > > > > > Erich > > > > 4BSD runs pretty well with an SMP kernel. I can test > ULE and compare > > easily. A no SMP kernel is problematic as the igb > driver doesn't seem > > to work and my onboard NICs are, sadly, igb. > > > this is bad luck. I know of the kernels as I have had SMP > and single > CPU machines since 4.x times. > > > Rather than say "depends what you want to do", perhaps > an explanation > > of which cases you might choose one or the other would > be helpful. > > > > So can anyone in the know confirm that the kernel > really isn't smart > > enough to know there there's only 1 core so that most > of the SMP > > The kernel does not think like this. It is a fixed program > flow. > > > "overhead" is avoided? It seems to me that SMP > scheduling should only > > be enabled if there is more than 1 core as part of the > scheduler > > initialization. Its arrogant indeed to assume that just > because SMP > > support is compiled in that there are multiple cores. > > I compile my own kernels and set the parameters as needed. > > Erich > This explanation defies the possibility of a GENERIC kernel, which of course is an important element of a GPOS. Its too bad that smp support can't be done with logic rather than a kernel option. The big thing I see is the use of legacy interrupts vs msix. Its not like flipping off SMP support only changes the scheduler behavior. BC