From owner-freebsd-arch@FreeBSD.ORG Wed Jul 10 13:55:57 2013 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id BB92B9AF for ; Wed, 10 Jul 2013 13:55:57 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from mail-ie0-f180.google.com (mail-ie0-f180.google.com [209.85.223.180]) by mx1.freebsd.org (Postfix) with ESMTP id 896011F2C for ; Wed, 10 Jul 2013 13:55:57 +0000 (UTC) Received: by mail-ie0-f180.google.com with SMTP id f4so15381911iea.11 for ; Wed, 10 Jul 2013 06:55:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=sender:subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to:x-mailer :x-gm-message-state; bh=07nk/aQWme3MiNCM8C94h2ngEPDYhO9qA/WkznsrLyI=; b=XDmGR7Q6K/l4In5/T3+kROrRZWe8vELsj0GiwFOiBM/uLbWy2e7PyoPKTUDWMidomU nKsMMBI/1Y8Zo2rc2TppX37HSOl8LiQzOLmRg0TvdggcOMQTk5v1RbUGV7TZik7gMl/t U8FNMvgFjdn0TrMCwcprMEZUezhjAhdFUshTgalXFDWzYPKv8sZrZx4FCV0tYRIzAFg0 pXWBx12Pj6lPYCnZEeLfgon2tD7c/XOZMCbXzNDkWVsl540RkWq0yozRGzPMWse2Cmzk UI71aNEgPjw3AmKr/lKqgdulXRokGj/nVG9XSkeKFsdUCNhX+y3ToBbx7S7H+JDuiLht iORw== X-Received: by 10.42.62.198 with SMTP id z6mr10111155ich.7.1373464556941; Wed, 10 Jul 2013 06:55:56 -0700 (PDT) Received: from 53.imp.bsdimp.com (50-78-194-198-static.hfc.comcastbusiness.net. [50.78.194.198]) by mx.google.com with ESMTPSA id ri10sm37567907igc.1.2013.07.10.06.55.55 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 10 Jul 2013 06:55:55 -0700 (PDT) Sender: Warner Losh Subject: Re: Adding a MACHINE_ARCH note Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Warner Losh In-Reply-To: <20130710070319.GX91021@kib.kiev.ua> Date: Wed, 10 Jul 2013 07:55:53 -0600 Content-Transfer-Encoding: quoted-printable Message-Id: References: <20130709090744.0e497e7e@bender.Home> <32F979BD-FB5C-4111-9586-4C5E7C6DFA71@bsdimp.com> <20130709234837.559e3769@bender.Home> <20130710070319.GX91021@kib.kiev.ua> To: Konstantin Belousov X-Mailer: Apple Mail (2.1085) X-Gm-Message-State: ALoCoQlv7eMziarww0sXaFzViCIV8Y4jqMzwTl1gVhC4VkfTy+vMle1Btg4ejE6ZcB07JNfJ0DXS Cc: Baptiste Daroussin , Adrian Chadd , Dimitry Andric , Andrew Turner , freebsd-arch@freebsd.org X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Jul 2013 13:55:57 -0000 On Jul 10, 2013, at 1:03 AM, Konstantin Belousov wrote: > On Wed, Jul 10, 2013 at 08:54:05AM +0200, Dimitry Andric wrote: >> On Jul 10, 2013, at 03:08, Peter Wemm wrote: >>> On Tue, Jul 9, 2013 at 5:56 PM, Adrian Chadd = wrote: >>>> ... boy I'd like to see this particular x86 hiccup fixed before = this >>>> stuff is mainstream. >>>=20 >>> I'm not entirely sure how much support there is behind "x32". I = don't >>> know if its much more than an academic curiosity or if there's real >>> demand for it. >>=20 >> It seems to be driven by Intel and Google. The idea is that for some >> applications (or maybe even most :), an ILP32 model will perform = better. >> Quoting from one of the presentations: >>=20 >> On Core i7 2600K 3.40GHz: >> - Improved SPEC CPU 2K/2006 INT geomean by 7-10% over ia32 and 5-8% = over >> Intel64. >> - Improved SPEC CPU 2K/2006 FP geomean by 5-11% over ia32. >> - Very little changes in SPEC CPU 2K/2006 FP geomean, comparing = against >> Intel64. >> - Comparing against ia32 PIC, x32 PIC: >> - Improved SPEC CPU 2K INT by another 10%. >> - Improved SPEC CPU 2K FP by another 3%. >> - Improved SPEC CPU 2006 INT by another 6% >> - Improved SPEC CPU 2006 FP by another 2%. >>=20 >> As to how often it is actually used in practice, I am not sure. >>=20 >>=20 >>> gcc-4.8 and clang have it, or have patches for it. >>=20 >> You also need a fairly recent binutils. And kernel + libc support... >> It is probably not a trivial task. :-) >=20 > You definitely need a support from libc, libthr and rtld. > I am not convinced that the kernel modifications are needed, > except for the image activator to recognize new ELF ids. In > other words, I believe it is better to put shims into libc in > the long run. For MIPS N32, you also need to make sure that the system calls grok the = ABI. You're going to give up some of the performance gains by shimming, = plus you run the risk of mixing x32 with amd64 code, which would be bad. = Attractive as it may sound to try to put it all in libc, I'm not = convinced that would work out in the end. Warner=