From owner-freebsd-current@FreeBSD.ORG Tue Sep 11 13:24:17 2012 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 7C53B106564A; Tue, 11 Sep 2012 13:24:17 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) by mx1.freebsd.org (Postfix) with ESMTP id 3E7618FC08; Tue, 11 Sep 2012 13:24:17 +0000 (UTC) Received: from troutmask.apl.washington.edu (localhost.apl.washington.edu [127.0.0.1]) by troutmask.apl.washington.edu (8.14.5/8.14.5) with ESMTP id q8BDOA3p087209; Tue, 11 Sep 2012 06:24:10 -0700 (PDT) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.14.5/8.14.5/Submit) id q8BDOATC087208; Tue, 11 Sep 2012 06:24:10 -0700 (PDT) (envelope-from sgk) Date: Tue, 11 Sep 2012 06:24:10 -0700 From: Steve Kargl To: Roman Divacky Message-ID: <20120911132410.GA87126@troutmask.apl.washington.edu> References: <20120910211207.GC64920@lor.one-eyed-alien.net> <20120911104518.GF37286@deviant.kiev.zoral.com.ua> <20120911120649.GA52235@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120911120649.GA52235@freebsd.org> User-Agent: Mutt/1.4.2.3i Cc: toolchain@freebsd.org, current@freebsd.org Subject: Re: Clang as default compiler November 4th X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Sep 2012 13:24:17 -0000 On Tue, Sep 11, 2012 at 02:06:49PM +0200, Roman Divacky wrote: > > > tl;dr: Clang will become the default compiler for x86 architectures on 2012-11-04 > > > Another issue with the switch, which seems to be not only not addressed, > > but even not talked about, is the performance impact of the change. I > > do not remember any measurements, whatever silly they could be, of the > > performance change by the compiler switch. We often have serious and > > argumented push-back for kernel changes that give as low as 2-3% of > > the speed hit. What are the numbers for clang change, any numbers ? > > Agreed. We should provide numbers. At least how buildworld times change > with clang compiled kernel/workd and gcc compiler kernel/world. How fast clang builds world in comparison to gcc is irrelevant. What is important is whether software built with clang functions correctly. See for example, http://math-atlas.sourceforge.net/errata.html#WhatComp Has anyone run Spec CPU2006 on i386 and amd64 FreeBSD? -- Steve