From owner-freebsd-arm@freebsd.org Sun Feb 7 04:44:13 2016 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8CE43AA00D6 for ; Sun, 7 Feb 2016 04:44:13 +0000 (UTC) (envelope-from erichsfreebsdlist@alogt.com) Received: from alogt.com (alogt.com [69.36.191.58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 70F07B66 for ; Sun, 7 Feb 2016 04:44:13 +0000 (UTC) (envelope-from erichsfreebsdlist@alogt.com) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=alogt.com; s=default; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-ID:Subject:Cc:To:From:Date; bh=avq6iFs2NLxw871MdPDC1dS/gFVMVsYl5u+hlYmVdmQ=; b=dr5Z36UbqYGEX4jBEPLM2HqnQ+ zn0GcCDX7CTwPyD/YxNBLcnB5twiTMEZQfpDnwBVwF7By9Qr4BtH3nVT6hk/V084xiBU1+6uSNzSu Ifsw19DIYLPRt97e5jzwUXbIZ2fhQse7UmjZYb9UB8JUv9qaoquuIjR2dQ34bHBHlsck=; Received: from [114.124.36.248] (port=55074 helo=X220.alogt.com) by sl-508-2.slc.westdc.net with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1aSHCl-004Kbv-5Q; Sat, 06 Feb 2016 21:44:11 -0700 Date: Sun, 7 Feb 2016 12:44:04 +0800 From: Erich Dollansky To: Warner Losh Cc: "freebsd-arm@freebsd.org" Subject: Re: clang++: error: the clang compiler does not support '-march=native' Message-ID: <20160207124404.186b395f@X220.alogt.com> In-Reply-To: References: <20160207050149.39f7e280@X220.alogt.com> <20160207095721.57fc3502@X220.alogt.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - sl-508-2.slc.westdc.net X-AntiAbuse: Original Domain - freebsd.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - alogt.com X-Get-Message-Sender-Via: sl-508-2.slc.westdc.net: authenticated_id: erichsfreebsdlist@alogt.com X-Authenticated-Sender: sl-508-2.slc.westdc.net: erichsfreebsdlist@alogt.com X-Source: X-Source-Args: X-Source-Dir: X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 07 Feb 2016 04:44:13 -0000 Hi, On Sat, 6 Feb 2016 21:01:13 -0700 Warner Losh wrote: > On Sat, Feb 6, 2016 at 6:57 PM, Erich Dollansky > > wrote: > > > On Sat, 6 Feb 2016 15:49:14 -0700 > > Warner Losh wrote: > > > > > On Sat, Feb 6, 2016 at 2:01 PM, Erich Dollansky > > > > > > wrote: > > > > > > > compiling on a Raspberry Pi B 2 on FreeBSD 11 gives me above's > > > > error message. > > > > > > > > A Internet search shows that this message does not exist. > > > > > > > > The program compiles using the same make file on FreeBSD 10 > > > > both on x86 and an Raspberry Pi B using the default compilers. > > > > > > > > Did support for 'march' get removed? > > > > > > > > > > As far as I can tell, it has never worked for either gcc or clang. > > > > > this is what I would have liked to find out. Intel claims speed > > gains of some 40% on their CPUs depending on the work load using > > gcc. > > > > Getting a few per cent on a Raspberry for free would make a real > > difference. > > > > Well, the -march= args work, just not -march=native. > The exact details of the core aren't exported from the kernel, so the > compiler can't easily query them to guess at the best code generation > to use. I think it would be a useful feature, but it just isn't one > we have yet. > > There are some -march values that get so aggressive about optimization > that they reveal some alignment issues. However, I think we've kill > them all. If not, we'd love to hear about it. > > I know that the -march=arm1176 works well for the RPi B. Last time I > tried it, the -march=cortex-a7 had some alignment issues. Since then > I've seen fixes go into the tree and I haven't tried again. Reports > from elsewhere indicate that this will give tens of percent in > improvement depending on the workload. > ok, I will try this then. Is there a list of working architectures somewhere which really applies for clang? I found only random information. Erich