From owner-freebsd-net@FreeBSD.ORG Tue Sep 15 11:33:09 2009 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7CF591065693 for ; Tue, 15 Sep 2009 11:33:09 +0000 (UTC) (envelope-from barney_cordoba@yahoo.com) Received: from n2a.bullet.mail.ac4.yahoo.com (n2a.bullet.mail.ac4.yahoo.com [76.13.13.65]) by mx1.freebsd.org (Postfix) with SMTP id 1A1668FC1D for ; Tue, 15 Sep 2009 11:33:08 +0000 (UTC) Received: from [76.13.13.25] by n2.bullet.mail.ac4.yahoo.com with NNFMP; 15 Sep 2009 11:33:08 -0000 Received: from [76.13.10.160] by t4.bullet.mail.ac4.yahoo.com with NNFMP; 15 Sep 2009 11:33:08 -0000 Received: from [127.0.0.1] by omp101.mail.ac4.yahoo.com with NNFMP; 15 Sep 2009 11:33:08 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 622729.11390.bm@omp101.mail.ac4.yahoo.com Received: (qmail 79835 invoked by uid 60001); 15 Sep 2009 11:33:08 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1253014388; bh=XANf9J3c/tRprohlQ+/k2JNYID8Py5nVRheIzck9JVQ=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=kd6IDiIw+2mV2QONNT3DZbC+OzA7mFxdoJW+t0/dC7/F7C7fmsPIsEs/QQeDgOSZmSWkf5v38pmB0BDve+Zhxnqk0kEaQ6XNZaoVuL+ysfelUaZBAMDvLXfsM5Of4WfF3stqwiX3K9OuzmaTDnfx/NqEbVJw32BvahbssVWNEnE= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=UzGxGOxiHOd9D3ho3g43y+9YfZDtgjYkKBflwTQLbPNeEotBmZjo0/D4+2g3o1pHS5bW79brGWYxQV45CUv6Zqu2BPkL56lsjx3lFdEPtKUerTAEiPXq4wLfyga0fJOMKLx6FZkvFpWjf2z8vDskDoRJeLPoyQFQbo44ORWqNjI=; Message-ID: <518979.77721.qm@web63907.mail.re1.yahoo.com> X-YMail-OSG: 7bqKTd0VM1mHKbY9t4H6iq6eUh0uaU44whShij5D.0o.sX1lNXHdxeJ98q8D2ldUuXX1WFAPp7ohUKMeEDzP9Qhr.lVVP0QOUoqz27qjHKi1JrVHpDglw9nLgjLMLgYkmD.G7VxS5BTjq_Ogj6Ghv.pY_tfEpflyuJd0x4ji53_MOc7Uz.G6d63t7eqpO3Q3Z2fqywytCg5EhlohAI1opEfbOAY_.4KtpTNJrtSl8eID9euVwlNSJKqUx4C2QQ0xOxf7k1fI0yeoDT8FzLeOgF4- Received: from [98.203.21.152] by web63907.mail.re1.yahoo.com via HTTP; Tue, 15 Sep 2009 04:33:08 PDT X-Mailer: YahooMailClassic/6.1.2 YahooMailWebService/0.7.347.2 Date: Tue, 15 Sep 2009 04:33:08 -0700 (PDT) From: Barney Cordoba To: peterjeremy@acm.org In-Reply-To: <20090915073830.GC48679@server.vk2pj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-net@freebsd.org Subject: Re: [POLLING] strange interrupt/system load X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Sep 2009 11:33:09 -0000 =0A=0A--- On Tue, 9/15/09, peterjeremy@acm.org wrote:= =0A=0A> From: peterjeremy@acm.org =0A> Subject: Re: [P= OLLING] strange interrupt/system load=0A> To: "Barney Cordoba" =0A> Cc: freebsd-net@freebsd.org=0A> Date: Tuesday, September= 15, 2009, 3:38 AM=0A> On 2009-Sep-13 07:19:24 -0700, Barney=0A> Cordoba =0A> wrote:=0A> >64bits must be faster than 32bits = is patently=0A> misguided. My rule of =0A> >thumb is that if I don't need 6= 4bits for something, I=0A> avoid it.=0A> =0A> It's not quite that cut-and-d= ry.=A0 The 64-bit ISA is=0A> significantly=0A> different to the 32-bit ISA = and has different subroutine=0A> calling=0A> conventions.=A0 Yes, you do ne= ed to lug 64-bit pointers=0A> around but the=0A> overall codesize is compar= able (looking at /usr/bin and=0A> /lib suggests=0A> about a 5% increase in = size going from i386 to amd64) - a=0A> lot of this=0A> is probably because = amd64 has a 16-bit offset mode so=0A> there's much=0A> less need for 32-bit= offsets.=A0 Having twice as many=0A> registers is a=0A> win in some areas = (less spilling to memory) and a loss in=0A> others (more=0A> state to save/= restore on a context switch).=0A> =0A> If performance is critical, it's pro= bably worthwhile=0A> benchmarking=0A> both i386 and amd64 variants and seei= ng which works best=0A> for you.=0A> =0A"Rules of Thumb" are generally for = those times when you don't have=0Aa pressing preference and you don't want = to spend your life endlessly=0Abenchmarking.=0A=0AI don't think its the cod= e, necessarity, but rather the significant=0Aincrease in the size of data s= tructures, and the memory that has to=0Abe moved around.=0A=0AI haven't tri= ed with the latest compiler but I can't see why it would=0Ahave any benefit= for systems used for high capacity networking other than=0Aincrementing co= unters. =0A=0ABarney=0A=0A=0A